i am eclipse user. so when i wanted to analyze my code with pmd, i needed to use “pmd for eclipse” plugin. this plugin used to be very buggy, which was enhanced in later versions (currently 4.0.3). but the performance is really bad sometimes. especially when you are dealing with relatively big codebase and have option “check code after saving” on. ecplise-pmd plugin so when i realized that there is new alternative pmd plugin called eclipse-pmd out there i evaluated it immediately with great happiness. installation uses modern eclipse marketplace method. you just need to go “help” -> “eclipse marketplace…” and search for “eclipse-pmd” . than hit “install” and follow instructions. after installation i was a little bit confused because i didn’t find any configuration options it general settings ( “window” -> “preferences” ). i discovered that you need to turn on pmd for each project separately. which make sense, because you can have different rule set per project. so to turn it on, right click on project -> “preferences” -> “pmd” (there would be two pmd sections if you didn’t uninstall old pmd plugin) -> “enable pmd for this project” -> “add…” . now you should pick a location of pmd ruleset file. unlike old pmd plugin, eclipse-pmd don’t import ruleset. it is using ruleset file directly. this is very handy, because typically you want to have it in source control. when you pull changes to ruleset file from source control system, they are applied without re-import (re-import was needed for old pmd plugin). problem can be when you (or your team) don’t have existing ruleset. i would suggest to start with full ruleset and exclude rules you don’t want to use. your ruleset would evolve anyway, so starting with most restrictive (default) deck make perfect sense for me. unfortunately eclipse-pmd plugin doesn’t provide option to generate ruleset file. so i created full ruleset for pmd 5.1.1 (5.1.1 is pmd version not plugin version) . i have to admit that it was created with help of old pmd plugin. you can see that i literally included all the rule categories. i would suggest to specify your set this way and exclude/configure rules explicitly as needed. here is link to pmd site that explains how to customize your ruleset . this approach can be handy when pmd version will be updated. new rules can appear in category and they will be automatically included into your ruleset when you are listing categories, not rules individually. but you have to keep eye on new rules/categories when updating pmd version anyway, because categories often change with new pmd version. so now we should have rulset configured and working. here are some screen shots of rules in action: when you hover over left side panel warning: when you hover over problematic snippet: when you do quick fix on problematic snippet: generating suppress warning annotation for pmd rules is very nice feature. it also provide quick fixes for some rules. take a look at its change log site for full list. these pmd warning sometimes clash with eclipse native warnings, so there is possibility to make them more visible. go to “window” -> “preferences” -> “general” -> “editors” -> “text editors” -> “annotations” and find “pmd violations” . here you can configure your own style of highlighting pmd issues. this is mine: to explore full feature list of this plugin take a look at its change log site. there are some features in old plugin i miss though. for example i would appreciate some quick link or full description of the rule. short description provided is sometimes not enough. i encourage you to take a look at full pmd rule description if you are not sure what’s source of the problem. you will learn a lot about java language itself or about libraries you are using. quick links would help a lot in such case. also some rules doesn’t use code highlighting (only side panel markers). it is sometimes hard to distinguish between compiler and pmd issues. this is problem for me because our team doesn’t use javadoc warnings but i do. so i get a lot of javadoc warnings from code written by teammates. and sometimes i can miss pmd issue because it is lost in javadoc warnings. (fortunately svn commit is rejected if i forget to fix some rule). conclusion this plugin enhanced my eclipse workflow. no more disruptions because of endless “checking code…” processing by old plugin.

Apparently writing a URL shortener service is the new "Hello, world!" in the IoT/microservice/era world. It all started with A URL shortener service in 45 lines of Scala - neat piece of Scala, flavoured with Spray and Redis for storage. This was quickly followed with A url shortener service in 35 lines of Clojure and even URL Shortener in 43 lines of Haskell. So my inner anti-hipster asked: how long would it be in Java? But not plain Java, for goodness' sake. Spring Boot with Spring Data Redis are a good starting point. All we need is a simple controller handling GET and POST: import com.google.common.hash.Hashing; import org.apache.commons.validator.routines.UrlValidator; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.SpringApplication; import org.springframework.data.redis.core.StringRedisTemplate; import org.springframework.http.*; import org.springframework.web.bind.annotation.*; import javax.servlet.http.*; import java.nio.charset.StandardCharsets; @org.springframework.boot.autoconfigure.EnableAutoConfiguration @org.springframework.stereotype.Controller public class UrlShortener { public static void main(String[] args) { SpringApplication.run(UrlShortener.class, args); } @Autowired private StringRedisTemplate redis; @RequestMapping(value = "/{id}", method = RequestMethod.GET) public void redirect(@PathVariable String id, HttpServletResponse resp) throws Exception { final String url = redis.opsForValue().get(id); if (url != null) resp.sendRedirect(url); else resp.sendError(HttpServletResponse.SC_NOT_FOUND); } @RequestMapping(method = RequestMethod.POST) public ResponseEntity save(HttpServletRequest req) { final String queryParams = (req.getQueryString() != null) ? "?" + req.getQueryString() : ""; final String url = (req.getRequestURI() + queryParams).substring(1); final UrlValidator urlValidator = new UrlValidator(new String[]{"http", "https"}); if (urlValidator.isValid(url)) { final String id = Hashing.murmur3_32().hashString(url, StandardCharsets.UTF_8).toString(); redis.opsForValue().set(id, url); return new ResponseEntity<>("http://mydomain.com/" + id, HttpStatus.OK); } else return new ResponseEntity<>(HttpStatus.BAD_REQUEST); } } The code is nicely self-descriptive and is functionally equivalent to a version in Scala. I didn't try to it squeeze too much to keep line count as short as possible, code above is quite typical with few details: I don't normally use wildcard imports I don't use fully qualified class names (I wanted to save one import line, I admit) I surround if/else blocks with braces I almost never use field injection, ugliest brother in inversion of control family. Instead I would go for constructor to allow testing with mocked Redis: private final StringRedisTemplate redis; @Autowired public UrlShortener(StringRedisTemplate redis) { this.redis = redis; } The thing I struggled the most was... obtaining the original, full URL. Basically I needed everything after .com or port. No bloody way (neither servlets, nor Spring MVC), hence the awkward getQueryString() fiddling. You can use the service as follows - creating shorter URL: $ curl -vX POST localhost:8080/https://www.google.pl/search?q=tomasz+nurkiewicz > POST /https://www.google.pl/search?q=tomasz+nurkiewicz HTTP/1.1 > User-Agent: curl/7.30.0 > Host: localhost:8080 > Accept: */* > < HTTP/1.1 200 OK < Server: Apache-Coyote/1.1 < Content-Type: text/plain;charset=ISO-8859-1 < Content-Length: 28 < Date: Sat, 23 Aug 2014 20:47:40 GMT < http://mydomain.com/50784f51 Redirecting through shorter URL: $ curl -v localhost:8080/50784f51 > GET /50784f51 HTTP/1.1 > User-Agent: curl/7.30.0 > Host: localhost:8080 > Accept: */* > < HTTP/1.1 302 Found < Server: Apache-Coyote/1.1 < Location: https://www.google.pl/search?q=tomasz+nurkiewicz < Content-Length: 0 < Date: Sat, 23 Aug 2014 20:48:00 GMT < For completeness, here is a build file in Gradle (maven would work as well), skipped in all previous solutions: buildscript { repositories { mavenLocal() maven { url "http://repo.spring.io/libs-snapshot" } mavenCentral() } dependencies { classpath 'org.springframework.boot:spring-boot-gradle-plugin:1.1.5.RELEASE' } } apply plugin: 'java' apply plugin: 'spring-boot' sourceCompatibility = '1.8' repositories { mavenLocal() maven { url 'http://repository.codehaus.org' } maven { url 'http://repo.spring.io/milestone' } mavenCentral() } dependencies { compile "org.springframework.boot:spring-boot-starter-web:1.1.5.RELEASE" compile "org.springframework.boot:spring-boot-starter-redis:1.1.5.RELEASE" compile 'com.google.guava:guava:17.0' compile 'org.apache.commons:commons-lang3:3.3.2' compile 'commons-validator:commons-validator:1.4.0' compile 'org.apache.tomcat.embed:tomcat-embed-el:8.0.9' compile "org.aspectj:aspectjrt:1.8.1" runtime "cglib:cglib-nodep:3.1" } tasks.withType(GroovyCompile) { groovyOptions.optimizationOptions.indy = true } task wrapper(type: Wrapper) { gradleVersion = '2.0' } Actually also 42 lines... That's the whole application, no XML, no descriptors, not setup. I don't treat this exercise as just a dummy code golf for shortest, most obfuscated working code. URL shortener web service with Redis back-end is an interesting showcase of syntax and capabilities of a given language and ecosystem. Much more entertaining then a bunch of algorithmic problems, e.g. found in Rosetta code. Also it's a good bare minimum template for writing a REST service. One important feature of original Scala implementation, that was somehow silently forgotten in all implementations, including this one, is that it's non-blocking. Both HTTP and Redis access is event-driven (reactive, all right, I said it), thus I suppose it can handle tens of thousands of clients simultaneously. This can't be achieved with blocking controllers backed by Tomcat. But still you have to admit such a service written in Java (not even Java 8!) is surprisingly concise, easy to follow and straightforward - none of the other solutions are that readable (this is of course subjective). Waiting for others!

Learn How to Enable Swagger in your Spring Boot Web Application

Once we know something, we find it hard to imagine what it was like not to know it. - Chip & Dan Heath, Authors of Made to Stick, Switch Update: I have recently published a book on ELK stack titled - Learning ELK Stack , more details can be found here. What is the ELK stack ? The ELK stack is ElasticSearch, Logstash and Kibana. These three provide a fully working real-time data analytics tool for getting wonderful information sitting on your data. ElasticSearch ElasticSearch,built on top of Apache Lucene, is a search engine with focus on real-time analysis of the data, and is based on the RESTful architecture. It provides standard full text search functionality and powerful search based on query. ElasticSearch is document-oriented/based and you can store everything you want as JSON. This makes it powerful, simple and flexible. Logstash Logstash is a tool for managing events and logs. You can use it to collect logs, parse them, and store them for later use.In ELK Stack logstash plays an important role in shipping the log and indexing them later which can be supplied to Elastic Search. Kibana Kibana is a user friendly way to view, search and visualize your log data, which will present the data stored from Logstash into ElasticSearch, in a very customizable interface with histogram and other panels which provides real-time analysis and search of data you have parsed into ElasticSearch. How Do I Get It ? http://www.elasticsearch.org/overview/elkdownloads/ How Do They Work Together ? Logstash is essentially a pipelining tool. In a basic, centralized installation a logstash agent, known as the shipper, will read input from one to many input sources and output that text wrapped in a JSON message to a broker. Typically Redis, the broker, caches the messages until another logstash agent, known as the collector, picks them up, and sends them to another output. In the common example this output is Elasticsearch, where the messages will be indexed and stored for searching. The Elasticsearch store is accessed via the Kibana web application which allows you to visualize and search through the logs. The entire system is scalable. Many different shippers may be running on many different hosts, watching log files and shipping the messages off to a cluster of brokers. Then many collectors can be reading those messages and writing them to an Elasticsearch cluster. (E)lasticSearch (L)ogstash (K)ibana (The ELK Stack) How Do I Fetch Useful Information Out of Logs? Fetching useful information from logs is one of the most important part of this stack and is being done in logstash using its grok filters and a set of input , filter and output plugins which helps to scale this functionality for taking various kinds of inputs ( file,tcp, udp, gemfire, stdin, unix, web sockets and even IRC and twitter and many more) , filter them using (groks,grep,date filters etc.) and finally write ouput to ElasticSearch,redis,email,HTTP,MongoDB,Gemfire , Jira , Google Cloud Storage etc. A Bit More About Log Stash Filters Transforming the logs as they go through the pipeline is possible as well using filters. Either on the shipper or collector, whichever suits your needs better. As an example, an Apache HTTP log entry can have each element (request, response code, response size, etc) parsed out into individual fields so they can be searched on more seamlessly. Information can be dropped if it isn’t important. Sensitive data can be masked. Messages can be tagged. The list goes on. e.g. input { file { path => ["var/log/apache.log"] type => "saurzcode_apache_logs" } } filter { grok { match => ["message","%{COMBINEDAPACHELOG}"] } } output{ stdout{} } Above example takes input from an apache log file applies a grok filter with %{COMBINEDAPACHELOG}, which will index apache logs information on fields and finally output to Standard Output Console. Writing Grok Filters Writing grok filters and fetching information is the only task that requires some serious efforts and if done properly will give you great insights in to your data like Number of Transations performed over time, Which type of products have most hits etc. Below links will help you a lot in writing grok filters and test them with ease - Grok Debugger http://grokdebug.herokuapp.com/ Grok Patterns Lookup https://github.com/elasticsearch/logstash/tree/v1.4.2/patterns References http://www.elasticsearch.org/overview/ http://logstash.net/ http://rashidkpc.github.io/Kibana/about.html

Hello, how are you? Today we will talk about situations in which the use of the JPA/Hibernate is not recommended. Which alternatives do we have outside the JPA world? What we will talk about: JPA/Hibernate problems Solutions to some of the JPA/Hibernate problems Criteria for choosing the frameworks described here Spring JDBC Template MyBatis Sormula sql2o Take a look at: jOOQ and Avaje Is a raw JDBC approach worth it? How can I choose the right framework? Final thoughts I have created 4 CRUDs in my github using the frameworks mentioned in this post, you will find the URL at the beginning of each page. I am not a radical that thinks that JPA is worthless, but I do believe that we need to choose the right framework for the each situation. If you do not know I wrote a JPA book (in Portuguese only) and I do not think that JPA is the silver bullet that will solve all the problems. I hope you like the post. [= JPA/Hibernate Problems There are times that JPA can do more harm than good. Below you will see the JPA/Hibernate problems and in the next page you will see some solutions to these problems: Composite Key: This, in my opinion, is the biggest headache of the JPA developers. When we map a composite key we are adding a huge complexity to the project when we need to persist or find a object in the database. When you use composite key several problems will might happen, and some of these problems could be implementation bugs. Legacy Database: A project that has a lot of business rules in the database can be a problem when wee need to invoke StoredProcedures or Functions. Artifact size: The artifact size will increase a lot if you are using the Hibernate implementation. The Hibernate uses a lot of dependencies that will increase the size of the generated jar/war/ear. The artifact size can be a problem if the developer needs to do a deploy in several remote servers with a low Internet band (or a slow upload). Imagine a project that in each new release it is necessary to update 10 customers servers across the country. Problems with slow upload, corrupted file and loss of Internet can happen making the dev/ops team to lose more time. Generated SQL: One of the JPA advantages is the database portability, but to use this portability advantage you need to use the JPQL/HQL language. This advantage can became a disadvantage when the generated query has a poor performance and it does not use the table index that was created to optimize the queries. Complex Query: That are projects that has several queries with a high level of complexity using database resources like: SUM, MAX, MIN, COUNT, HAVING, etc. If you combine those resources the JPA performance might drop and not use the table indexes, or you will not be able to use a specific database resource that could solve this problem. Framework complexity: To create a CRUD with JPA is very simples, but problems will appear when we start to use entities relationships, inheritance, cache, PersistenceUnit manipulation, PersistenceContext with several entities, etc. A development team without a developer with a good JPA experience will lose a lot of time with JPA ‘rules‘. Slow processing and a lot of RAM memory occupied: There are moments that JPA will lose performance at report processing, inserting a lot of entities or problems with a transaction that is opened for a long time. After reading all the problems above you might be thinking: “Is JPA good in doing anything?”. JPA has a lot of advantages that will not be detailed here because this is not the post theme, JPA is a tool that is indicated for a lot of situations. Some of the JPA advantages are: database portability, save a lot of the development time, make easier to create queries, cache optimization, a huge community support, etc. In the next page we will see some solutions for the problems detailed above, the solutions could help you to avoid a huge persistence framework refactoring. We will see some tips to fix or to workaround the problems described here. Solutions to Some of the JPA/Hibernate problems We need to be careful if we are thinking about removing the JPA of our projects. I am not of the developer type that thinks that we should remove a entire framework before trying to find a solution to the problems. Some times it is better to choose a less intrusive approach. Composite Key Unfortunately there is not a good solution to this problem. If possible, avoid the creation of tables with composite key if it is not required by the business rules. I have seen developers using composite keys when a simple key could be applied, the composite key complexity was added to the project unnecessarily. Legacy Databases The newest JPA version (2.1) has support to StoredProcedures and Functions, with this new resource will be easier to communicate with the database. If a JPA version upgrade is not possible I think that JPA is not the best solution to you. You could use some of the vendor resources, e.g. Hibernate, but you will lose database and implementations portability. Artifact Size An easy solution to this problem would be to change the JPA implementation. Instead of using the Hibernate implementation you could use the Eclipsellink, OpenJPA or the Batoo. A problem might appear if the project is using Hibernate annotation/resources; the implementation change will require some code refactoring. Generated SQL and Complexes Query The solution to these problems would be a resource named NativeQuery. With this resource you could have a simplified query or optimized SQL, but you will sacrifice the database portability. You could put your queries in a file, something like SEARCH_STUDENTS_ORACLE or SEARCH_STUDENTS_MYSQL, and in production environment the correct file would be accessed. The problem of this approach is that the same query must be written for every database. If we need to edit the SEARCH_STUDENTS query, it would be required to edit the oracle and mysql files. If your project is has only one database vendor the NativeQuery resource will not be a problem. The advantage of this hybrid approach (JPQL and NativeQuery in the same project) is the possibility of using the others JPA advantages. Slow Processing and Huge Memory Size This problem can be solved with optimized queries (with NativeQuery), query pagination and small transactions. Avoid using EJB with PersistenceContext Extended, this kind of context will consume more memory and processing of the server. There is also the possibility of getting an entity from database as a “read only” entity, e.g.: entity that will only be used in a report. To recover an entity in a “read only” state is not needed to open a transaction, take a look at the code below: String query = "select uai from Student uai"; EntityManager entityManager = entityManagerFactory.createEntityManager(); TypedQuery typedQuery = entityManager.createQuery(query, Student.class); List resultList = typedQuery.getResultList(); Notice that in the code above there is no opened transaction, all the returned entities will be detached (non monitored by the JPA). If you are using EJB mark your transaction as NOT_SUPPORTED or you could use @Transactional(readOnly=true). Complexity I would say that there is only one solution to this problem: to study. It will be necessary to read books, blogs, magazines or any other trustful source of JPA material. More study is equals to less doubts in JPA. I am not a developer that believes that JPA it is the only and the best solution to every problem, but there are moments that JPA is not the best to tool to use. You must be careful when deciding about a persistence framework change, usually a lot of classes are affected and a huge refactoring is needed. Several bugs may be caused by this refactoring. It is needed to talk with the project mangers about this refactoring and list all the positive and negative effects. In the next four pages we will see 4 persistence frameworks that can be used in our projects, but before we see the frameworks I will show how that I choose each framework. Criteria for Choosing the frameworks Described Here Maybe you will think: “why the framework X is not here?”. Below I will list the criteria applied for choosing the framework displayed here: Found in more than one source of research: we can find in forums people talking about a framework, but it is harder to find the same framework appearing in more than one forum. The most quoted frameworks were chosen. Quoted by different sources: Some frameworks that we found in the forums are indicated only by its committers. Some forums does not allow “self merchandise”, but some frameworks owners still doing it. Last update 01/05/2013: I have searched for frameworks that have been updated in this past year. Quick Hello World: Some frameworks I could not do a Hello World with less than 15~20min, and with some errors. To the tutorials found in this post I have worked 7 minutes in each framework: starting counting in its download until the first database insert. The frameworks that will be displayed in here has good methods and are easy to use. To make a real CRUD scenario we have a persistence model like below: A attribute with a name different of the column name: socialSecurityNumber —-> social_security_number A date attribute a ENUM attribute With this characteristics in a class we will see some problems and how the framework solve it. Spring JDBC Template One of the most famous frameworks that we can find to access the database data is the Spring JDBC Template. The code of this project can be found in here: https://github.com/uaihebert/SpringJdbcTemplateCrud The Sprint JDBC Template uses natives queries like below: As it is possible to see in the image above the query has a database syntax (I will be using MySQL). When we use a native SQL query it is possible to use all the database resources in an easy way. We need an instance of the object JDBC Template (used to execute the queries), and to create the JDBC Template object we need to set up a datasource: We can get the datasource now (thanks to the Spring injection) and create our JDBCTemplate: PS.: All the XML code above and the JDBCTemplate instantiation could be replace by Spring injection and with a code bootstrap, just do a little research about the Spring features. One thing that I did not liked is the INSERT statement with ID recover, it is very verbose: With the KeyHolder class we can recover the generated ID in the database, unfortunately we need a huge code to do it. The other CRUD functions are easier to use, like below: Notice that to execute a SQL query it is very simple and results in a populated object, thanks to the RowMapper. The RowMapper is the engine that the JDBC Template uses to make easier to populate a class with data from the database. Take a look at the RowMapper code below: The best news about the RowMapper is that it can be used in any query of the project. The developer that is responsible to write the logic that will populate the class data. To finish this page, take a look below in the database DELETE and the database UPDATE statement: About the Spring JDBC Template we can say: Has a good support: Any search in the Internet will result in several pages with tips and bug fixes. A lot of companies use it: several projects across the world use it Be careful with different databases for the same project: The native SQL can became a problem with your project run with different databases. Several queries will need to be rewritten to adapt all the project databases. Framework Knowledge: It is good to know the Spring basics, how it can be configured and used. To those that does not know the Spring has several modules and in your project it is possible to use only the JDBC Template module. You could keep all the other modules/frameworks of your project and add only the necessary to run the JDBC Template. MyBatis MyBatis (created with the name iBatis) is a very good framework that is used by a lot of developers. Has a lot of functionalities, but we will only see a few in this post. The code of this page can be found in here: https://github.com/uaihebert/MyBatisCrud To run your project with MyBatis you will need to instantiate a Session Factory. It is very easy and the documentation says that this factory can be static: When you run a project with MyBatis you just need to instantiate the Factory one time, that is why it is in a static code. The configuration XML (mybatis.xml) it is very simple and its code can be found below: The Mapper (an attribute inside the XML above) will hold information about the project queries and how to translate the database result into Java objects. It is possible to create a Mapper in XML or Interface. Let us see below the Mapper found in the file crud_query.xml: Notice that the file is easy to understand. The first configuration found is a ResultMap that indicates the query result type, and a result class was configured “uai.model.Customer”. In the class we have a attribute with a different name of the database table column, so we need to add a configuration to the ResultMap. All queries need a ID that will be used by MyBatis session. In the beginning of the file it is possible to see a namespace declared that works as a Java package, this package will wrap all the queries and the ResultMaps found in the XML file. We could also use a Interface+Annotation instead of the XML. The Mapper found in the crud_query.xml file could be translated in to a Interface like: Only the Read methods were written in the Interface to make the code smaller, but all the CRUD methods could be written in the Interface. Let us see first how to execute a query found in the XML file: The parsing of the object is automatically and the method is easy to read. To run the query all that is needed is to use the combination “namespace + query id” that we saw in the crud_query.xml code above. If the developer wants to use the Interface approach he could do like below: With the interface query mode we have a clean code and the developer will not need to instantiate the Interface, the session class of the MyBatis will do the work. If you want to update, delete or insert a record in the database the code is very easy: About MyBatis we could say: Excellent Documentation: Every time that I had a doubt I could answer it just by reading its site documentation Flexibility: Allowing XML or Interfaces+Annotations the framework gives a huge flexibility to the developer. Notice that if you choose the Interface approach the database portability will be harder, it is easier to choose which XML to send with the deploy artifact rather than an interface Integration: Has integration with Guice and Spring Dynamic Query: Allows to create queries in Runtime, like the JPA criteria. It is possible to add “IFs” to a query to decide which attribute will be used in the query Transaction: If your project is not using Guice of Spring you will need to manually control the transaction Sormula Sormula is a ORM OpenSource framework, very similar to the JPA/Hibernate. The code of the project in this page can be found in here: https://github.com/uaihebert/SormulaCrud Sormula has a class named Database that works like the JPA EntityManagerFactory, the Database class will be like a bridge between the database and your model classes. To execute the SQL actions we will use the Table class that works like the JPA EntityManager, but the Table class is typed. To run Sormula in a code you will need to create a Database instance: To create a Database instance all that we need is a Java Connection. To read data from the database is very easy, like below: You only need to create a Database instance and a Table instance to execute all kind of SQL actions. How can we map a class attribute name different from the database table column name? Take a look below: We can use annotations to do the database mapping in our classes, very close to the JPA style. To update, delete or create data in the database you can do like below: About Sormula we can say that: Has a good documentation Easy to set up It is not found in the maven repository, it will make harder to attach the source code if needed Has a lot of checked exceptions, you will need to do a try/catch for the invoked actions sql2o This framework works with native SQL and makes easier to transform database data into Java objects. The code of the project in this page can be found in here: https://github.com/uaihebert/sql2oCrud sql2o has a Connection class that is very easy to create: Notice that we have a static Sql2o object that will work like a Connection factory. To read the database data we would do something like: Notice that we have a Native SQL written, but we have named parameters. We are not using positional parameters like ‘?1′ but we gave a name to the parameter like ‘:id’. We can say that named parameters has the advantage that we will not get lost in a query with several parameters; when we forget to pass some parameter the error message will tell us the parameter name that is missing. We can inform in the query the name of the column with a different name, there is no need to create a Mapper/RowMapper. With the return type defined in the query we will not need to instantiate manually the object, sql2o will do it for us. If you want to update, delete or insert data in the database you can do like below: It is a “very easy to use” framework. About the sql2o we can say that: Easy to handle scalar query: the returned values of SUM, COUNT functions are easy to handle Named parameters in query: Will make easy to handle SQL with a lot of parameters Binding functions: bind is a function that will automatically populate the database query parameters through a given object, unfortunately it did not work in this project for a problem with the enum. I did not investigate the problem, but I think that it is something easy to handle Take a look at: jOOQ and Avaje jOOQ jOOQ it is a framework indicated by a lot of people, the users of this frameworks praise it in a lot of sites/forums. Unfortunately the jOOQ did not work in my PC because my database was too old, and I could not download other database when writing this post (I was in an airplane). I noticed that to use the jOOQ you will need to generated several jOOQ classes based in your model. jOOQ has a good documentation in the site and it details how to generate those classes. jOOQ is free to those that uses a free database like: MySQL, Postgre, etc. The paid jOOQ version is needed to those that uses paid databases like: Oracle, SQL Server, etc. www.jooq.org/ Avaje Is a framework quoted in several blogs/forums. It works with the ORM concept and it is easy to execute database CRUD actions. Problems that I found: Not well detailed documentation: its Hello World is not very detailed Configurations: it has a required properties configuration file with a lot of configurations, really boring to those that just want to do a Hello World A Enhancer is needed: enhancement is a method do optimize the class bytecode, but is hard to setup in the beginning and is mandatory to do before the Hello World www.avaje.org Is a Raw JDBC Approach Worth It? The advantages of JDBC are: Best performance: We will not have any framework between the persistence layer and the database. We can get the best performance with a raw JDBC Control over the SQL: The written SQL is the SQL that will be executed in the database, no framework will edit/update/generate the query SQL Native Resource: We could access all natives database resources without a problem, e.g.: functions, stored procedures, hints, etc The disadvantages are: Verbose Code: After receiving the database query result we need to instantiate and populate the object manually, invoking all the required “set” methods. This code will get worse if we have classes relationships like one-to-many. It will be very easy to find a while inside another while. Fragile Code: If a database table column changes its name it will be necessary to edit all the project queries that uses this column. Some project uses constants with the column name to help with this task, e.g. Customer.NAME_COLUMN, with this approach the table column name update would be easier. If a column is removed from the database all the project queries would be updated, even if you have a column constants. Complex Portability: If your project uses more than one database it would be necessary to have almost all queries written for each vendor. For any update in any query it would be necessary to update every vendor query, this could take a lot the time from the developers. I can see only one factor that would make me choose a raw JDBC approach almost instantly: Performance: If your project need to process thousands of transactions per minutes, need to be scalable and with a low memory usage this is the best choice. Usually median/huge projects has all this high performance requirements. It is also possible to have a hybrid solution to the projects; most of the project repository (DAO) will use a framework, and just a small part of it will use JDBC I do like JDBC a lot, I have worked and I still working with it. I just ask you to not think that JDBC is the silver bullet for every problem. If you know any other advantage/disadvantage that is not listed here, just tell me and I will add here with the credits going to you. [= How Can I Choose the Right Framework? We must be careful if you want to change JPA for other project or if you are just looking for other persistence framework. If the solutions in page 3 are not solving your problems the best solution is to change the persistence framework. What should you considerate before changing the persistence framework? Documentation: is the framework well documented? Is easy to understand how it works and can it answer most of your doubts? Community: has the framework an active community of users? Has a forum? Maintenance/Fix Bugs: Is the framework receiving commits to fix bugs or receiving new features? There are fix releases being created? With which frequency? How hard is to find a developer that knows about this framework? I believe that this is the most important issue to be considered. You could add to your project the best framework in the world but without developers that know how to operate it the framework will be useless. If you need to hire a senior developer how hard would be to find one? If you urgently need to hire someone that knows that unknown framework maybe this could be very difficult. Final Thoughts I will say it again: I do not think that JPA could/should be applied to every situation in every project in the world; I do no think that that JPA is useless just because it has disadvantages just like any other framework. I do not want you to be offended if your framework was not listed here, maybe the research words that I used to find persistence frameworks did not lead me to your framework. I hope that this post might help you. If your have any double/question just post it. [= See you soon! \o_

the article represents steps required to configure tomcat 8 with eclipse kepler. download tomcat 8 and place it within any local folder. download eclipse java ee kepler as of date, tomcat 8 is not supported in eclipse javeee kepler. however, you could add the tomcat 8 by doing following: go to the wtp downloads page, select the latest version (currently 3.6), and download the zip. here’s the current link . copy the all of the files in features and plugins directories of the downloaded wtp into the corresponding eclipse directories in your eclipse folder (overwriting the existing files). start eclipse and click on “servers” tab in the workbench. go ahead and try adding a new server. you would find option for tomcat 8 available for selection as shown below. after clicking finish, you would see a new server added with the name as “tomcat v8.0 server at localhost”. start the server. check http://localhost:8080 (provided you installed tomcat 8 and set http port as 8080) interestingly, you would not see the welcome page, but the 404 error page. to get rid of that, double click on ”tomcat v8.0 server at localhost”. in the window that opens up, select “use tomcat installation” and, change deploy path from wtpwebapps to webapps. look at the figure below. restart the server and access http://localhost:8080 . you are all set.

One of the things that one must get used to with a new language is dealing with new conventions. Now coming from mostly a Java and Ruby background, there is a notion of constructors and constructor chaining, basically when one constructor calls another one. So when it comes to Swift, there are a few rules around the methods used to create objects. Firstly, the language guide refers to constructors as initializers. So basically anytime you want to use the term constructor, use the term initializer when you are in Swift land. More specifically, constructor chaining is known as initializer delegation. Initializers fall into two categories, Designated and Convenience.Designated initializers are the primary initializers and are responsible for initializing all properties of a class. So in this case, the only initializer here is known as the Designated one. class Person { let name: String let age: Int init(name: String, age: Int) { self.name = name self.age = age } } Now if you want to add other initializers to delegate to the Designated one, they will be known as Convenience initializers. So let's add one that defaults the age. Convenience initializers have the keyword conveniencebefore them. class Person { let name: String let age: Int init(name: String, age: Int) { self.name = name self.age = age } convenience init(name: String) { self.init(name: name, age: 100) } } Convenience initializers need to delegate to another Convenienceinitializer or a Designated initializer. Here's an example of a Convenience initializer calling another Convenienceone. class Person { let name: String let age: Int init(name: String, age: Int) { self.name = name self.age = age } convenience init(name: String) { self.init(name: name, age: 30) } convenience init() { self.init(name: "Homer") } } If you wanted to, you could create another Designated initializer. Now we have two Designated initializers and two Convenience initializers. class Person { let name: String let age: Int init(name: String, age: Int) { self.name = name self.age = age } init(age: Int, name: String) { self.age = age self.name = name } convenience init(name: String) { self.init(name: name, age: 30) } convenience init() { self.init(name: "Homer") } } What about subclasses? Once again, with initializers, there are certain rules that need to be adhered to when subclassing. So Designated initializers must call otherDesignated initializers in their immediate parent class. So let's take a look at an example. We are adding a Student class as a subclass of the Person class. It will add a property student number. class Student : Person { let number: String init(name: String, age: Int, number: String) { self.number = number super.init(name: name, age: age) } } Here we are calling the Designated initializer in the Person class. If we tried to call one of the Convenience initializers in the Person class, a compile error would occur. Also note, we need to assign the number property before calling the initializer in the parent class as it is a requirement to ensure all properties are initialized in child classes before their respective parent initializer is called. Summary Basically in summary, as explained in the language guide, Designatedinitializers delegate up and Convenience initializers delegate across. I hope this article helped in some way to improve your understanding of initializers in Swift. References Swift Language Guide

I have a small Spring boot based application that uses a Postgres database as a datastore. I wanted to document the steps involved in deploying this sample application to Cloud Foundry. Some of the steps are described in the Spring Boot reference guide, however the guides do not sufficiently explain how to integrate with the datastore provided in a cloud based environment. Spring-cloud provides the glue to connect Spring based applications deployed on a Cloud to discover and connect to bound services, so the first step is to pull in the Spring-cloud libraries into the project with the following pom entries: org.springframework.cloud spring-cloud-spring-service-connector 1.0.0.RELEASE org.springframework.cloud spring-cloud-cloudfoundry-connector 1.0.0.RELEASE Once this dependency is pulled in, connecting to a bound service is easy, just define a configuration along these lines: @Configuration public class PostgresCloudConfig extends AbstractCloudConfig { @Bean public DataSource dataSource() { return connectionFactory().dataSource(); } } Spring-Cloud understands that the application is deployed on a specific Cloud(currently Cloud Foundry and Heroku by looking for certain characteristics of the deployed Cloud platform), discovers the bound services, recognizes that there is a bound service using which a Postgres based datasource can be created and returns the datasource as a Spring bean. This application can now deploy cleanly to a Cloud Foundry based Cloud. The sample application can be tried out in a version of Cloud Foundry deployed with bosh-lite, these are how the steps in my machine looks like once Cloud Foundry is up and running with bosh-lite: The following command creates a user provided service in Cloud Foundry: cf create-user-provided-service psgservice -p '{"uri":"postgres://postgres:p0stgr3s@bkunjummen-mbp.local:5432/hotelsdb"}' Now, push the app, however don't start it up. We can do that once the service above is bound to the app: cf push spring-boot-mvc-test -p target/spring-boot-mvc-test-1.0.0-SNAPSHOT.war --no-start Bind the service to the app and restart the app: cf bind-service spring-boot-mvc-test psgservice cf restart spring-boot-mvc-test That is essentially it, Spring Cloud should ideally take over at the point and cleanly parse the credentials from the bound service which within Cloud Foundry translates to an environment variable called VCAP_SERVICES, and create the datasource from it. There is however an issue with this approach - once the datasource bean is created using spring-cloud approach, it does not work in a local environment anymore. The potential fix for this is to use Spring profiles, assume that there is a different "cloud" Spring profile available in Cloud environment where the Spring-cloud based datasource gets returned: @Profile("cloud") @Configuration public class PostgresCloudConfig extends AbstractCloudConfig { @Bean public DataSource dataSource() { return connectionFactory().dataSource(); } } and let Spring-boot auto-configuration create a datasource in the default local environment, this way the configuration works both local as well as in Cloud. Where does this "cloud" profile come from, it can be created using a ApplicationContextInitializer, and looks this way: public class SampleWebApplicationInitializer implementsApplicationContextInitializer { private static final Log logger = LogFactory.getLog(SampleWebApplicationInitializer.class); @Override public void initialize(AnnotationConfigEmbeddedWebApplicationContext applicationContext) { Cloud cloud = getCloud(); ConfigurableEnvironment appEnvironment = applicationContext.getEnvironment(); if (cloud!=null) { appEnvironment.addActiveProfile("cloud"); } logger.info("Cloud profile active"); } private Cloud getCloud() { try { CloudFactory cloudFactory = new CloudFactory(); return cloudFactory.getCloud(); } catch (CloudException ce) { return null; } } } This initializer makes use of the Spring-cloud's scanning capabilities to activate the "cloud" profile. One last thing which I wanted to try was to make my local behave like Cloud atleast in the eyes of Spring-Cloud and this can be done by adding in some environment variables using which Spring-Cloud makes the determination of the type of cloud where the application is deployed, the following is my startup script in local for the app to pretend as if it is deployed in Cloud Foundry: read -r -d '' VCAP_APPLICATION <<'ENDOFVAR' {"application_version":"1","application_name":"spring-boot-mvc-test","application_uris":[""],"version":"1.0","name":"spring-boot-mvc-test","instance_id":"abcd","instance_index":0,"host":"0.0.0.0","port":61008} ENDOFVAR export VCAP_APPLICATION=$VCAP_APPLICATION read -r -d '' VCAP_SERVICES <<'ENDOFVAR' {"postgres":[{"name":"psgservice","label":"postgresql","tags":["postgresql"],"plan":"Standard","credentials":{"uri":"postgres://postgres:p0stgr3s@bkunjummen-mbp.local:5432/hotelsdb"}]} ENDOFVAR export VCAP_SERVICES=$VCAP_SERVICES mvn spring-boot:run This entire sample is available at this github location:https://github.com/bijukunjummen/spring-boot-mvc-test Conclusion Spring Boot along with Spring-Cloud project now provide an excellent toolset to create Spring-powered cloud ready applications, and hopefully these notes are useful in integrating Spring Boot with Spring-Cloud and using these for seamless local and Cloud deployments.

Spring Integration (SI) is a framework enabling a collection of individual applications to integrate together to deliver a business enterprise system. The framework is essentially a lightweight messaging system that enables spring based applications to communicate with one another and supports integration with external systems via declarative adaptors. It is based on the 'filters and pipes' design architecture. A key feature of it is that it achieves this integration in a minimally intrusive way. The framework is built on 3 main components: Messages Encapsulate the data to be transferred from one place to another. They comprise of a header (holds meta data such as message-id, timestamp, etc) and a payload (your data typically in the form of a POJO). Channels Provide a mechanism to transport messages from one endpoint to another. Represents the pipes in the pipes & filters architecture. SI offers two types of channels, namely Pollable and Subscribable Channels. The former rely on consumers to periodically check for messages whereas the latter is directly responsible for notifying registered consumers when messages become available. Endpoints Consumer/Producer of messages. Performs some action based on the payload. Endpoints come in various flavours, each performing a different function. These include Transformers (transform data), Routers (route data), Filters (filter data), Splitter (splits messages), Aggregator (aggregates group of messages into single message), Service Activator (connecting messages to Services) and Channel Adapters (connect channels to external applications). The basic idea behind the SI framework is that applications communicate with each other by sending/receiving messages. These messages would typically contain the information (payload) required by the next application in the process pipeline. The transport of messages from one application to another is performed by Channel components. The Endpoints perform some action based on the payload. This could be routing the messages to another endpoint or processing the payload itself. The objective of this post is to provide an introduction to Spring Integration. To help achieve this, I developed a sample application which will be discussed below. The source for this sample application is available at here. The project was built and run using spring-integration-4.0.0, maven 3.2.1 and jdk1.6. The main dependency is for the relevant spring-integration jar as declared in the pom.xml: org.springframework.integration spring-integration-stream 4.0.0.RC1 I ran the application using the maven exec plugin. This allows me to clean, package and run the application by invoking mvn clean package exec:java -P OnlineShop from the command line. Developing a sample application: Tabernus My goal as usual was to build something very simple which would help me to become familiar with key concepts of this framework and to this end I've knocked up a simple app which does not connect up individual systems but rather invokes methods on a POJO. Extending this to actual working applications shouldn't be too difficult. The scenario I'm going to model revolves around purchasing items from an online store (Tabernus). This store only sells 3 types of items: Books, Music CDs, and software. During a Sale, the owners have decided to apply different discounts based on the item type. In this instance books, music and software benefit from discounts of 5%, 10%, and 15% respectively. The following diagram shows our domain entities. The class diagram shows that a Customer can place an Order comprising of a number of OrderItems which are of type Book, MusicCD or Software. The problem I need to solve is to design a system which can interrogate each Order and apply the correct discount based on the item type. Subsequently it should be able to compute the total cost of the order once the discounts have been applied. To model this using Spring Integration we need the following pipeline The above diagram shows various components most of which can be divided into 2 categories, channels (blue cylinder shapes) and endpoints (rectangular boxes). The exception to this is the Poller component whose purpose is to enable the various endpoints to function correctly and discussion of it will be given later. We'll start off by briefly covering the various stages in this pipeline as indicated by the numbers in red. Following this we will delve deeper into how we build this pipeline using the SI framework. The pipeline is comprised of 6 major stages as reflected by the numbers in the diagram, The Gateway component represents the entry point to the messaging system. All new Orders will be submitted to this component which will in turn wrap them as messages and place them into the channel appropriately named ordersChannel. Using the Splitter component - each Order is decomposed into a collection of it's constituent OrderItem instances. Each of these is wrapped in a Message and placed in the orderItemsChannel. The Router component considers each OrderItem in turn and places it in the relevant channel, e.g. Book items will be placed in the bookItemsChannel etc. This allows us to consider the different item types separately. The ServiceActivator needs to consider messages within each of the 3 channels and calculate the correct discount based on the channel. After completing the calculation for each OrderItem, it will place the OrderItem in the processedItemsChannel. The Aggregator component will collect all OrderItem instances placed in the processedItemsChannel and reconstruct the original Order. This will subsequently be placed in the deliveriesChannel, which represents the end of the pipeline. The Poller Component is required to configure how often the various endpoints will interrogate their respective input channels for messages. To implement the pipeline shown above using the SI framework, we need to implement the various end points. configure the pipeline in an xml file (Shop.xml) - identifying the various channels and endpoints and how they wire up together. At this point I should mention that SI offers 2 approach to configuring your process pipeline, annotations based and xml. In this article I'll be using the latter. Let's start to look at some code. We'll consider each stage described above and show the java implementation of the endpoint and xml configuration required to wire up the components. Step 1 - Gateway To begin with, we need to implement the Client that will invoke the Gateway component to place the Order. The client (OnlineShop.java) is shown below, public class OnlineShop { public static void main(String[] args) { AbstractApplicationContext context = new ClassPathXmlApplicationContext("/META-INF/com/prodcod/shop.xml", OnlineShop.class); Shop shop = (Shop) context.getBean("shop"); final Order order = createOrder(); shop.placeOrder(order); context.close(); } The logic here is quite simple. The client creates a dummy Order and passes this as an argument when it invokes the placeOrder() method on the gateway component. The gateway component referred here as Shop is injected by Spring. The Gateway component looks like: // Gateway component public interface Shop { @Gateway(requestChannel="ordersChannel") void placeOrder(Order order); } As you can see, this is simply an interface, whose implementation will be provided by Spring when it is injected into the client application. This is achieved by the use of the @Gateway annotation which informs Spring that this is a Gateway component and it needs to provide the implementation. Additionally the annotation accepts an attribute, requestChannel which defines the channel on which the Order instance will be placed. The framework does this by simply wrapping our instance of Order within a Message instance and placing it in the channel, 'ordersChannel'. The Gateway component and the 'ordersChannel' are declared as follows in the file shop.xml Step 2 - Splitter The next end point is the Splitter component. Appropriately named, it's role is to take a single message containing a payload of a collection of items and splitting it into a number of messages, each of which contains a single element from the collection. In our case, we want to decompose the Order into it's constituent OrderItem instances. It does this by taking a Message containing the payload of Order from 'ordersChannel' and then processing it before sending messages (each containing an OrderItem instance) to the 'orderItemsChannel'. Our implementation of the splitter is called OrderSplitter and is defined as below, public class OrderSplitter extends AbstractMessageSplitter{ @Override protected Object splitMessage(Message message) { return ((Order)message.getPayload()).getOrderItems(); } } Implementing a splitter is quite easy and involves extending the AbstractMessageSplitter class and overriding the splitMessage() method. This simply takes a message containing the payload of Order and returns it's collection of OrderItems. Step 3 - Router Having decomposed the Order into it's constituent OrderItems, we now need to separate them into groups of Books, MusicCD, and Software. This is achieved using a router. Our implementation of the Router looks like, public class OrderItemRouter { public String routeOrder(OrderItem orderItem) { String channel = ""; if(isBook(orderItem)) { channel = "bookItemsChannel"; } else if(isMusic(orderItem)) { channel = "musicItemsChannel"; } else if(isSoftware(orderItem)) { channel = "softwareItemsChannel"; } return channel; } ..................... ..................... } Nothing too complicated here. For each OrderItem, the method routeOrder() will determine it's item type and return the name of the channel that this message should be sent to. The channel name is returned by the method. Spring will then ensure that the message containing the OrderItem is relayed to the named channel. The configuration for OrderItemRouter looks like, The config identifies that the class OrderItemRouter is a Router component which will consume messages from the orderItemsChannel. Further Spring needs to invoke the method routeOrder() which contains the logic to perform the routing. The channels for each item type are declared as follows Step 4 - ServiceActivator The next step is to calculate the discounted price for each item type and this is performed by a ServiceActivator component. This is implemented as follows public class Shopkeeper { private static final BigDecimal BOOK_DISCOUNT = new BigDecimal(0.05); private static final BigDecimal MUSIC_DISCOUNT = new BigDecimal(0.10); private static final BigDecimal SOFTWARE_DISCOUNT = new BigDecimal(0.15); /** * Performs discount on books * @param bookOrderItem OrderItem comprising of a book item * @return OrderItem with discount price newly calculated */ public OrderItem processBooks(OrderItem bookOrderItem){ final BigDecimal finalPrice = calculateDiscountedPrice(bookOrderItem, BOOK_DISCOUNT); bookOrderItem.setDiscountedPrice(finalPrice); return bookOrderItem; } /** * Performs discount on music * @param musicOrderItem OrderItem comprising of a music item * @return OrderItem with discount price newly calculated */ public OrderItem processMusic(OrderItem musicOrderItem){ final BigDecimal finalPrice = calculateDiscountedPrice(musicOrderItem, MUSIC_DISCOUNT); musicOrderItem.setDiscountedPrice(finalPrice); return musicOrderItem; } /** * Performs discount on software * @param softwareOrderItem OrderItem comprising of a book item * @return OrderItem with discount price newly calculated */ public OrderItem processSoftware(OrderItem softwareOrderItem){ final BigDecimal finalPrice = calculateDiscountedPrice(softwareOrderItem, SOFTWARE_DISCOUNT); softwareOrderItem.setDiscountedPrice(finalPrice); return softwareOrderItem; } } This class exposes 3 methods to compute the new discounted price for each item type. Each method returns the OrderItem instance with the new price. The ServiceActivator is configured as follows: This tells Spring that the Shopkeeper class is a ServiceActivator and will consume messages from any of the 3 channels defined in the input-channel attribute. When a message appears in one of these channels, Spring will invoke the appropriate method on the ServiceActivator class as specfied by the attribute method. Anything returned from all three methods will be placed in the processedItems channel, ready for the next step of the processing pipeline. Step 5 - Aggregator The final stage is to take the individual OrderItems with their newly computed discounted prices and reconstruct the Order. This is achieved using an aggregator. Our implementation of an aggregator is listed below public class OrderCompleter { public Order prepareDelivery(List orderItems) { final Order order = new Order(); order.setOrderItems(orderItems); return order; } } The aggregator exposes a method that takes a collection of OrderItem objects. These will come from the processedItems channel declared as Recall this is the output channel for the service activator class as discussed above. The aggregator is configured in the xml file as The configuration tells Spring that the aggregator component will consume messages from the processedItems channel. These will be processed by the method prepareDelivery on the class OrderCompleter. Any output from this class will be relayed to the channel-adaptor deliveries, which is declared as The stdout-channel-adapter component writes to the systems STDOUT output stream. Step 6 - Poller To complete the setup we have to configure a poller component. This is required to enable the channels to work correctly. All our channels are of a queue type and so their respective consumers need to know when to query them. This is achieved using a poller mechanism. It is configured in the following way In this case, we have declared a global poller (as indicated by the default attribute). This will be used by the various end points to determine when they should interrogate their respective input-channels for messages. The second attribute fixed-delay is used to configure the polling interval. Running the Application Building and running the app shows the following output: The logging shows that the Customer submitted an Order for 3 items, one of each type. All items cost £100 each. The Order was then split into 3 OrderItems each of which was routed to the correct processing channel based on the item type. The ServiceActivator (Shopkeeper) then calculated the discount for each item and this was set on the OrderItem instance. The OrderItems were then aggregated using the OrderCompleter class which displays the final discounted price of £270 to be paid by the Customer. Note that the messages are logged to be in different stages of the processing pipeline despite starting off in the same order. This completes the tutorial on the Spring Integration Framework. Any comments relating to corrections, omissions, etc are welcome.

Before some time I have written a post about Getting Started with Nhibernate and ASP.NET MVC –CRUD operations. It’s one of the most popular post blog post on my blog. I get lots of questions via email and other medium why you are not writing a post about Fluent Nhibernate and ASP.NET MVC. So I thought it will be a good idea to write a blog post about it. What is Fluent Nhibernate: Convection over configuration that is mantra of Fluent Hibernate If you have see the my blog post about Nhibernate then you might have found that we need to create xml mapping to map table. Fluent Nhibernate uses POCO mapping instead of XML mapping and I firmly believe in Convection over configuration that is why I like Fluent Nhibernate a lot. But it’s a matter of Personal Test and there is no strong argument why you should use Fluent Nhibernate instead of Nhibernate. Fluent Nhibernate is team Comprises of James Gregory, Paul Batum, Andrew Stewart and Hudson Akridge. There are lots of committers and it’s a open source project. You can find all more information about at following site. http://www.fluentnhibernate.org/ On this site you can find definition of Fluent Nhibernate like below. Fluent, XML-less, compile safe, automated, convention-based mappings for NHibernate. Get your fluent on. They have excellent getting started guide on following url. You can easily walk through it and learned it. https://github.com/jagregory/fluent-nhibernate/wiki/Getting-started ASP.NET MVC and Fluent Nhibernate: So all set it’s time to write a sample application. So from visual studio 2013 go to file – New Project and add a new web application project with ASP.NET MVC. Once you are done with creating a web project with ASP.NET MVC It’s time to add Fluent Nhibernate to Application. You can add Fluent Nhibernate to application via following NuGet Package. And you can install it with package manager console like following. Now we are done with adding a Fluent Nhibernate to it’s time to add a new database. Now I’m going to create a simple table called “Employee” with four columns Id, FirstName, LastName and Designation. Following is a script for that. CREATE TABLE [dbo].[Employee] ( [Id] INT NOT NULL PRIMARY KEY, [FirstName] NVARCHAR(50) NULL, [LastName] NVARCHAR(50) NULL, [Designation] NVARCHAR(50) NULL ) Now table is ready it’s time to create a Model class for Employee. So following is a code for that. namespace FluentNhibernateMVC.Models { public class Employee { public virtual int EmployeeId { get; set; } public virtual string FirstName { get; set; } public virtual string LastName { get; set; } public virtual string Designation{ get; set; } } } Now Once we are done with our model classes and other stuff now it’s time to create a Map class which map our model class to our database table as we know that Fluent Nhibernate is using POCO classes to map instead of xml mappings. Following is a map class for that. using FluentNHibernate.Mapping; namespace FluentNhibernateMVC.Models { public class EmployeeMap : ClassMap { public EmployeeMap() { Id(x => x.EmployeeId); Map(x => x.FirstName); Map(x => x.LastName); Map(x => x.Designation); Table("Employee"); } } } If you see Employee Map class carefully you will see that I have mapped Id column with EmployeeId in table and another things you can see I have written a table with “Employee” which will map Employee class to employee class. Now once we are done with our mapping class now it’s time to add Nhibernate Helper which will connect to SQL Server database. using FluentNHibernate.Cfg; using FluentNHibernate.Cfg.Db; using NHibernate; using NHibernate.Tool.hbm2ddl; namespace FluentNhibernateMVC.Models { public class NHibernateHelper { public static ISession OpenSession() { ISessionFactory sessionFactory = Fluently.Configure() .Database(MsSqlConfiguration.MsSql2008 .ConnectionString(@"Data Source=(LocalDB)\v11.0;AttachDbFilename=C:\data\Blog\Samples\FluentNhibernateMVC\FluentNhibernateMVC\FluentNhibernateMVC\App_Data\FNhibernateDemo.mdf;Integrated Security=True") .ShowSql() ) .Mappings(m => m.FluentMappings .AddFromAssemblyOf()) .ExposeConfiguration(cfg => new SchemaExport(cfg) .Create(false, false)) .BuildSessionFactory(); return sessionFactory.OpenSession(); } } } Now we are done with classes It’s time to scaffold our Controller for the application. Right click Controller folder and click on add new controller. It will ask for scaffolding items like following. I have selected MVC5 controller with read/write action. Once you click Add It will ask for controller name. Now our controller is ready. It’s time to write code for our actions. Listing: Following is a code for our listing action. public ActionResult Index() { using (ISession session = NHibernateHelper.OpenSession()) { var employees = session.Query().ToList(); return View(employees); } } You add view for listing via right click on View and Add View. That’s is you are done with listing of your database. I have added few records to database table to see whether its working or not. Following is a output as expected. Create: Now it’s time to create code and views for creating a Employee. Following is a code for action results. public ActionResult Create() { return View(); } // POST: Employee/Create [HttpPost] public ActionResult Create(Employee employee) { try { using (ISession session = NHibernateHelper.OpenSession()) { using (ITransaction transaction = session.BeginTransaction()) { session.Save(employee); transaction.Commit(); } } return RedirectToAction("Index"); } catch (Exception exception) { return View(); } } Here you can see one if for blank action and another for posting data and saving to SQL Server with HttpPost Attribute. You can add view for create via right click on view on action result like following. Now when you run this you will get output as expected. Once you click on create it will return back to listing screen like this. Edit: Now we are done with listing/adding employee it’s time to write code for editing/updating employee. Following is a code Action Methods. public ActionResult Edit(int id) { using (ISession session = NHibernateHelper.OpenSession()) { var employee = session.Get(id); return View(employee); } } // POST: Employee/Edit/5 [HttpPost] public ActionResult Edit(int id, Employee employee) { try { using (ISession session = NHibernateHelper.OpenSession()) { var employeetoUpdate = session.Get(id); employeetoUpdate.Designation = employee.Designation; employeetoUpdate.FirstName = employee.FirstName; employeetoUpdate.LastName = employee.LastName; using (ITransaction transaction = session.BeginTransaction()) { session.Save(employeetoUpdate); transaction.Commit(); } } return RedirectToAction("Index"); } catch { return View(); } } You can create edit view via following via right click on view. Now when you run application it will work as expected. Details: You can write details code like following. public ActionResult Details(int id) { using (ISession session = NHibernateHelper.OpenSession()) { var employee = session.Get(id); return View(employee); } } You can view via right clicking on view as following. Now when you run application following is a output as expected. Delete: Following is a code for deleting Employee one action method for confirmation of delete and another one for deleting data from employee table. public ActionResult Delete(int id) { using (ISession session = NHibernateHelper.OpenSession()) { var employee = session.Get(id); return View(employee); } } [HttpPost] public ActionResult Delete(int id, Employee employee) { try { using (ISession session = NHibernateHelper.OpenSession()) { using (ITransaction transaction = session.BeginTransaction()) { session.Delete(employee); transaction.Commit(); } } return RedirectToAction("Index"); } catch (Exception exception) { return View(); } } You can add view for delete via right click on view like following. When you run it’s running as expected. Once you click on delete it will delete employee. That’s it. You can see it’s very easy. Fluent Nhibernate supports POCO mapping without writing any complex xml mappings. You can find whole source code at GitHub at following location. https://github.com/dotnetjalps/FluentNhiberNateMVC Hope you like it. Stay tuned for more!!

You should by now have worked your way through Part 1: Getting Started with Ansible. If you haven't, go and do that now. In this article, I'll be demonstrating a very simple application deployment workflow, deploying an insanely simple node.js application from a github repository, and configuring it to start with supervisord, and be reverse-proxied with Nginx. As with last time, we'll be using Parallax as the starting point for this. I've actually gone through and put the config in there already (if you don't feel like doing it yourself ;) - name: Install all the packages and stuff required for a demobox hosts: demoboxes user: user sudo: yes roles: - redis - nginx - nodejs - zeromq # - deploy_thingy In the 9c818d0b8f version, you'll be able to see that I've created a new role, inventively called "deploy_thingy". **Updated** I've been recommended that my __template__ role be based on the output of ansible-galaxy init $rolename So I've recreated the __template__ role to be based on an ansible-galaxy role template. There's not that many changes, but it does include a new directory 'default/' containing the Galaxy metadata required if you wish to push back to the public galaxy role index. In an attempt to make creating new roles easier, I put a __template__ role into the file tree when I first created Parallax, so that all you do to create a new role is execute: cp -R __template__ new_role_name in the roles/ directory. . ├── files │ ├── .empty │ ├── thingy.nginx.conf │ └── thingy.super.conf ├── handlers │ ├── .empty │ └── main.yml ├── meta │ ├── .empty │ └── main.yml ├── tasks │ └── main.yml └── templates └── .empty In this role, we define some dependencies in meta/main.yml, there's two files in the files/ directory, and there's a set of tasks defined in tasks/main.yml. There's also some handlers defined in handlers/main.yml. Let's have a quick glance at the meta/main.yml file. --- dependencies: - { role: nodejs } - { role: nginx } This basically sets the requirement that this role, deploy_thingy depends on services installed by the roles: nginx and nodejs. Although these roles are explicitly stated to be installed in site.yml, this gives us a level of belt-and-braces configuration, in case the deploy_thingy role were ever included without the other two roles being explicitly stated, or if it were configured to run before its dependencies had explicitly been set to run. tasks/main.yml is simple. --- - name: Create directory under /srv for thingy file: path=/srv/thingy state=directory mode=755 - name: Git checkout from github git: repo=https://github.com/tomoconnor/shiny-octo-computing-machine.git dest=/srv/thingy - name: Drop Config for supervisord into the conf.d directory copy: src=thingy.super.conf dest=/etc/supervisor/conf.d/thingy.conf notify: reread supervisord - name: Drop Reverse Proxy Config for Nginx copy: src=thingy.nginx.conf dest=/etc/nginx/sites-enabled/thingy.conf notify: restart nginx We'll create somewhere for it to live, check the code out of my git repository [1], Then drop two config files in place, one to configure supervisor(d), and one to configure Nginx. Because the command to configure supervisor(d) and nginx change the configuration of those services, there are notify: handlers to reload the configuration, or restart the service. Let's have a quick peek at those handlers now: --- - name: reread supervisord shell: /usr/bin/supervisorctl reread && /usr/bin/supervisorctl update - name: restart nginx service: name=nginx state=restarted When the supervisor config changes (and we add something to /etc/supervisor/conf.d), we need to tell supervisord to re-read it's configuration files, at which point, it will see the new services, and then run supervisorctl update, which will set the state of the newly added items from 'available' to 'started'. When we change the nginx configuration, we'll hit nginx with a restart. It's possible to do softer actions, like reload here, but I've chosen service restart for simplicity. I've also changed the basic Ansible config, and configuration of roles/common/files/insecure_sudoers so that it will still ask you for a sudo password in light of some minor criticism. I've found that if you're developing Ansible playbooks on an isolated system, then there's no great harm in disabling SSH Host Key Checking (in ansible.cfg), similarly how there's no great problems in disabling sudo authentication, so it's effectively like NOPASSWD use. However, Micheil made a very good point that in live environments it's a bit dodgy to say the least. So I've commented those lines out of the playbook in Parallax, so that it should give users a reasonable level of basic security. At the end of the day, it's up to you how you use Parallax, and if you find that disabling security works for you, then fine. It's not like you haven't been warned. But I digress. The next thing to do is to edit site.yml, and ensure that the new role we've created gets mapped to a hostgroup in the play configuration. In the latest version of Parallax this is already done for you, but as long as the role name in the list matches the directory in roles/, it should be ready to go. Now if we run: ansible-playbook -k -K -i playbooks/example/hosts playbooks/example/site.yml It should go through the playbook, installing stuff, then finally do the git clone from github, deploy the configuration files, and trigger a reread of supervisord, and a restart of nginx. If I now test that it's working, with: curl -i http://192.168.20.151/ HTTP/1.1 200 OK Server: nginx/1.4.1 (Ubuntu) Date: Mon, 27 Jan 2014 14:51:29 GMT Content-Type: text/html; charset=utf-8 Content-Length: 170 Connection: keep-alive X-Powered-By: Express ETag: "1827834703" That X-Powered-By: Express line shows that Nginx is indeed working, and that the node.js application is running too. You can get more information about stuff that supervisord is controlling by running: sudo supervisorctl status on the target host. $ sudo supervisorctl status thingy RUNNING pid 19756, uptime 0:00:06 If the Nginx side is configured, but the node.js application isn't running, you'd get a HTTP 502 error, as follows: curl -i http://192.168.20.151/ HTTP/1.1 502 Bad Gateway Server: nginx/1.4.1 (Ubuntu) Date: Mon, 27 Jan 2014 14:59:34 GMT Content-Type: text/html Content-Length: 181 Connection: keep-alive So, that's it. A very simple guide to deploying a very simple application with Ansible. Of course, it should be obvious that you can deploy *anything* from a git repository, it really boils down to the configuration of supervisord. For that matter, it doesn't have to be supervisord. I consider configuring supervisord for process controlling to be outside of the scope of this article, but I might touch on it in future in more detail. Next up, Part 3: Ansible and Amazon Web Services. 1: It's really simple, and I'm not very node-savvy, so I'm sorry if it sucks.

This is a first post in a series of short code snippets that will present the configuration of Spring beans from XML to Java. XML: resource.loader=class class.resource.loader.class=org.apache.velocity.runtime.resource.loader.ClasspathResourceLoader Java @Bean public VelocityEngine velocityEngine() throws VelocityException, IOException{ VelocityEngineFactoryBean factory = new VelocityEngineFactoryBean(); Properties props = new Properties(); props.put("resource.loader", "class"); props.put("class.resource.loader.class", "org.apache.velocity.runtime.resource.loader." + "ClasspathResourceLoader"); factory.setVelocityProperties(props); return factory.createVelocityEngine(); }

I blogged about this a few days ago, but I think I'm ready to really release my Cordova Brackets extension. The code is pretty much crap and it's really lacking in providing good feedback while it works, but the initial feature list is complete. Assuming you've got the Cordova CLI installed already, you can, via Brackets: Add and remove platforms. Warning - if Cordova needs to grab the bits for the platform (it does this once), it will be slow, and again, my extension isn't providing feedback about the operation until it is done, so, like, don't do anything. Go get coffee. Emulate for a platform. Not use run. It doesn't work, which means I kinda lied when I said the initial feature list was complete, but I'm OK with that. List plugins, along with the version. Add plugins, and I've got a nice autocomplete so you can quickly find the right plugin. Remove plugins too. There are bugs around this, so, be careful. You can see this in action in this thrilling video below. Oddly it is a bit out of focus for the first few seconds, but then it clears up. I blame gremlins. It is now available via the Extension Manager so you can install it directly from within Brackets. If you want to help work on the source, pull a fork over at https://github.com/cfjedimaster/Cordova-Extension. If you really like it, visit the Amazon wishlist and pick up that Marvel Lego game. ;)

recently, i had to put on my system administrator cap for couple of hours. i was to set up two dell poweredge 1720 server computers for use as test servers. the two servers were to run microsoft windows server 2012 r2 and that .net framework 3.5 must be enabled on the servers as it is one of the requirements needed by the enterprise application to be installed on the servers. enabling .net framework 3.5 on windows server 2012 r2 can be done through the server manager by clicking on add roles and features and then under features selecting .net framework 3.5 or through command prompt or windows power shell. as it is microsoft’s custom to put the required files for required role or features in the side-by-side folder. one would have thought that .net framework 3.5 files should be in the folder also as it is in windows server 2012’s side-by-side folder. so an attempt to enable .net framework 3.5 on windows server 2012 r2 would give an error “that installation of one or more roles, role services or features failed. the source file could not be found” like the one shown in the picture below. this means that the .net framework 3.5 (which includes 3.0 and 2.0) files are not included in windows server 2012 r2 setup. if the server is connected to the internet and it has windows update enabled, the framework can be pulled from the internet and added to the windows installation folder by the os when enabling the feature. but the servers i was configuring had no internet connections which means that there was no way the framework could be pulled from the internet. what i did was to copy the side-by-side folder from windows server 2012 setup, (not windows server 2012 r2 setup) since it contains the files needed to install the .net 3.5 framework, i then ran command prompt as an administrator with the following commands. dism.exe /online /enable-feature /featurename:netfx3serverfeatures /source:d:\sxs to enable the feature dism.exe /online /enable-feature /featurename:netfx3 /source:d:\sxs /limitaccess to install the feature where d:\sxs is the path of the folder containing the required files that i copied from windows server 2012 setup side-by-side folder. i hope i have been able to save someone precious time.

This is a sample that I have wanted to try for sometime - A Websocket application to tail the contents of a file. The following is the final view of the web-application: There are a few parts to this application: Generating a File to tail: I chose to use a set of 100 random quotes as a source of the file content, every few seconds the application generates a quote and writes this quote to the temporary file. Spring Integration is used for wiring this flow for writing the contents to the file: Just a quick note, Spring Integration flows can now also be written using a Java Based DSL, and this flow using Java is available here Tailing the file and sending the content to a broker The actual tailing of the file itself can be accomplished by OS specific tail command or by using a library like Apache Commons IO. Again in my case I decided to use Spring Integration which provides Inbound channel adapters to tail a file purely using configuration, this flow looks like this: and its working Java equivalent There is a reference to a "fileContentRecordingService" above, this is the component which will direct the lines of the file to a place where the Websocket client will subscribe to. Websocket server configuration Spring Websocket support makes it super simple to write a Websocket based application, in this instance the entire working configuration is the following: @Configuration @EnableWebSocketMessageBroker public class WebSocketDefaultConfig extends AbstractWebSocketMessageBrokerConfigurer { @Override public void configureMessageBroker(MessageBrokerRegistry config) { //config.enableStompBrokerRelay("/topic/", "/queue/"); config.enableSimpleBroker("/topic/", "/queue/"); config.setApplicationDestinationPrefixes("/app"); } @Override public void registerStompEndpoints(StompEndpointRegistry registry) { registry.addEndpoint("/tailfilesep").withSockJS(); } } This may seem a little over the top, but what these few lines of configuration does is very powerful and the configuration can be better understood by going through the reference here. In brief, it sets up a websocket endpoint at '/tailfileep' uri, this endpoint is enhanced with SockJS support, Stomp is used as a sub-protocol, endpoints `/topic` and `/queue` is configured to a real broker like RabbitMQ or ActiveMQ but in this specific to an in-memory one. Going back to the "fileContentRecordingService" once more, this component essentially takes the line of the file and sends it this in-memory broker, SimpMessagingTemplate facilitates this wiring: public class FileContentRecordingService { @Autowired private SimpMessagingTemplate simpMessagingTemplate; public void sendLinesToTopic(String line) { this.simpMessagingTemplate.convertAndSend("/topic/tailfiles", line); } } Websocket UI configuration The UI is angularjs based, the client controller is set up this way and internally uses the javascript libraries for sockjs and stomp support: var tailFilesApp = angular.module("tailFilesApp",[]); tailFilesApp.controller("TailFilesCtrl", function ($scope) { function init() { $scope.buffer = new CircularBuffer(20); } $scope.initSockets = function() { $scope.socket={}; $scope.socket.client = new SockJS("/tailfilesep); $scope.socket.stomp = Stomp.over($scope.socket.client); $scope.socket.stomp.connect({}, function() { $scope.socket.stomp.subscribe("/topic/tailfiles", $scope.notify); }); $scope.socket.client.onclose = $scope.reconnect; }; $scope.notify = function(message) { $scope.$apply(function() { $scope.buffer.add(angular.fromJson(message.body)); }); }; $scope.reconnect = function() { setTimeout($scope.initSockets, 10000); }; init(); $scope.initSockets(); }); The meat of this code is the "notify" function which the callback acting on the messages from the server, in this instance the new lines coming into the file and showing it in a textarea. This wraps up the entire application to tail a file. A complete working sample without any external dependencies is available at this github location, instructions to start it up is also available at that location. Conclusion Spring Websockets provides a concise way to create Websocket based applications, this sample provides a good demonstration of this support. I had presented on this topic recently at my local JUG (IndyJUG) and a deck with the presentation is available here

In this post, I will show how to integrate Apache Tiles 3 with Spring MVC.

Get familiar with the Angular JS origin story.

in my last post on extjs 4 mvc, i have demonstrated the use of extjs 4 mvc to create a simple create-read-update-delete application using extjs only. today we will go to see how to use that extjs part for ui and use spring mvc to manage the books records on server side using spring. let first start by creating spring’s webmvc configurer class. i am using spring’s new xml-free approach and if you are new to it, i recommend you to please go through my previous post. package org.techzoo.springmvc.bootstrap; import org.springframework.context.annotation.bean; import org.springframework.context.annotation.componentscan; import org.springframework.context.annotation.configuration; import org.springframework.web.servlet.config.annotation.enablewebmvc; import org.springframework.web.servlet.config.annotation.resourcehandlerregistry; import org.springframework.web.servlet.config.annotation.viewcontrollerregistry; import org.springframework.web.servlet.config.annotation.webmvcconfigureradapter; import org.springframework.web.servlet.view.internalresourceviewresolver; @configuration @enablewebmvc @componentscan(basepackages = {"org.techzoo.springmvc"}) public class mywebmvcconfigurer extends webmvcconfigureradapter { @override public void addresourcehandlers(resourcehandlerregistry registry) { registry.addresourcehandler("/resources/**") .addresourcelocations("/resources/"); } @override public void addviewcontrollers(viewcontrollerregistry registry) { registry.addviewcontroller("/") .setviewname("index"); } @bean public internalresourceviewresolver viewresolver() { internalresourceviewresolver resolver = new internalresourceviewresolver(); resolver.setprefix("/web-inf/views/"); resolver.setsuffix(".jsp"); return resolver; } } create a book bean now, this bean is work as a value object and represent a single record in grid. package org.techzoo.springmvc.vo; /** * author: tousif khan */ public class book { private int id; private string title; private string author; private int price; private int qty; public book() {} public book(int id, string title, string author, int price, int qty) { super(); this.id = id; this.title = title; this.author = author; this.price = price; this.setqty(qty); } //getter-setters goes here... @override public string tostring() { return string.format("book [title = %s, author = %s]", title, author); } } now create a bookdao interface and implement it. package org.techzoo.springmvc.dao; import java.util.list; import org.springframework.stereotype.component; import org.techzoo.springmvc.vo.book; @component public interface bookdao { public boolean addbook(book book); public void updatebook(book book); public list listbooks(); public book getbookbyid(integer bookid); public boolean removebook(book book); } to make it more simple, i am using book list but you can extend it to save it relational table. see my springmvc-hibernate grud tutorial for more details. package org.techzoo.springmvc.dao; import java.util.arraylist; import java.util.list; import org.springframework.stereotype.repository; import org.techzoo.springmvc.vo.book; @repository public class bookdaoimpl implements bookdao { private static list books = new arraylist(); static { books.add(new book(1001, "jdbc, servlet and jsp", "santosh kumar", 300, 12000)); books.add(new book(1002, "head first java", "kathy sierra", 550, 2500)); books.add(new book(1003, "java scjp certification", "khalid mughal", 650, 5500)); books.add(new book(1004, "spring and hinernate", "santosh kumar", 350, 2500)); books.add(new book(1005, "mastering c++", "k. r. venugopal", 400, 1200)); } @override public boolean addbook(book book) { return books.add(book); } @override public boolean removebook(book book) { return books.remove(book); } @override public list listbooks() { return books; } @override public void updatebook(book book) { int index = books.indexof(book); if(index != -1) { books.add(index, book); } } @override public book getbookbyid(integer bookid) { book b = null; for(book b1 : books) { if(b1.getid() == bookid) { return b1; } } return b; } } now it’s time to create a book controller. package org.techzoo.springmvc.controller; import java.util.hashmap; import java.util.list; import java.util.map; import org.springframework.beans.factory.annotation.autowired; import org.springframework.stereotype.controller; import org.springframework.validation.objecterror; import org.springframework.web.bind.methodargumentnotvalidexception; import org.springframework.web.bind.annotation.exceptionhandler; import org.springframework.web.bind.annotation.requestbody; import org.springframework.web.bind.annotation.requestmapping; import org.springframework.web.bind.annotation.requestmethod; import org.springframework.web.bind.annotation.responsebody; import org.techzoo.springmvc.dao.bookdao; import org.techzoo.springmvc.vo.book; @controller @requestmapping("api") public class bookcontroller { bookdao bookbao; @autowired public bookcontroller(bookdao bookbao) { this.bookbao = bookbao; } @requestmapping(value = "/index") public string index() { return "index"; } @requestmapping (value = "book/save", method = requestmethod.post) @responsebody public boolean savebook(@requestbody book book) { return bookbao.addbook(book); } @responsebody @requestmapping (value = "book/loadbooks") public map> loadallbooks() { map> books = new hashmap>(); books.put("books", bookbao.listbooks()); return books; } @requestmapping (value = "book/delete", method = requestmethod.post) @responsebody public boolean deletebooks(@requestbody book book) { return bookbao.removebook(book); } @requestmapping (value = "book/updatebook", method = requestmethod.post) @responsebody public boolean updatebooks(@requestbody book book) { bookbao.updatebook(book); return true; } } extjs code looks similar to previous example with a little change. i have changes the local store to server ajax proxy and after each delete/add/update operation, we will load the all record from server to make grid update. ext.onready(function () { ext.define('techzoo.model.book', { extend: 'ext.data.model', fields: [ {name: 'id', type: 'int'}, {name: 'title', type: 'string'}, {name: 'author', type: 'string'}, {name: 'price', type: 'int'}, {name: 'qty', type: 'int'} ] }); ext.define('techzoo.store.books', { extend : 'ext.data.store', storeid: 'bookstore', model : 'techzoo.model.book', fields : ['id', 'title', 'author','price', 'qty'], proxy: { type: 'ajax', url: '/springmvc-extjs-crud/api/book/loadbooks', reader: { type: 'json', root: 'books' } }, autoload: true }); ext.define('techzoo.view.bookslist', { extend: 'ext.grid.panel', alias: 'widget.bookslist', title: 'books list - (extjs springmvc example - @ tousif khan)', store: 'books', initcomponent: function () { this.tbar = [{ text : 'add book', action : 'add', iconcls : 'book-add' }]; this.columns = [ { header: 'title', dataindex: 'title', flex: 1 }, { header: 'author', dataindex: 'author' }, { header: 'price', dataindex: 'price' , width: 60 }, { header: 'quantity', dataindex: 'qty', width: 80 }, { header: 'action', width: 50, renderer: function (v, m, r) { var id = ext.id(); ext.defer(function () { ext.widget('image', { renderto: id, name: 'delete', src : 'resources/images/book_delete.png', listeners : { afterrender: function (me) { me.getel().on('click', function() { var grid = ext.componentquery.query('bookslist')[0]; if (grid) { var sm = grid.getselectionmodel(); var rs = sm.getselection(); if (!rs.length) { ext.msg.alert('info', 'no book selected'); return; } ext.msg.confirm('remove book', 'are you sure you want to delete?', function (button) { if (button == 'yes') { //grid.store.remove(rs[0]); var book = rs[0].getdata(); ext.ajax.request({ url: '/springmvc-extjs-crud/api/book/delete', method : 'post', jsondata: book, success: function(response){ var grid = ext.componentquery.query('bookslist')[0]; grid.getstore().load(); } }); } }); } }); } } }); }, 50); return ext.string.format('', id); } } ]; this.callparent(arguments); } }); ext.define('techzoo.view.booksform', { extend : 'ext.window.window', alias : 'widget.booksform', title : 'add book', width : 350, layout : 'fit', resizable: false, closeaction: 'hide', modal : true, config : { recordindex : 0, action : '' }, items : [{ xtype : 'form', layout: 'anchor', bodystyle: { background: 'none', padding: '10px', border: '0' }, defaults: { xtype : 'textfield', anchor: '100%' }, items : [{ name : 'title', fieldlabel: 'book title' },{ name: 'author', fieldlabel: 'author name' },{ name: 'price', fieldlabel: 'price' },{ name: 'qty', fieldlabel: 'quantity' }] }], buttons: [{ text: 'ok', action: 'add' },{ text : 'reset', handler : function () { this.up('window').down('form').getform().reset(); } },{ text : 'cancel', handler: function () { this.up('window').close(); } }] }); ext.define('techzoo.controller.books', { extend : 'ext.app.controller', stores : ['books'], views : ['bookslist', 'booksform'], refs : [{ ref : 'formwindow', xtype : 'booksform', selector: 'booksform', autocreate: true }], init: function () { this.control({ 'bookslist > toolbar > button[action=add]': { click: this.showaddform }, 'bookslist': { itemdblclick: this.onrowdblclick }, 'booksform button[action=add]': { click: this.doaddbook } }); }, onrowdblclick: function(me, record, item, index) { var win = this.getformwindow(); win.settitle('edit book'); win.setaction('edit'); win.setrecordindex(index); win.down('form').getform().setvalues(record.getdata()); win.show(); }, showaddform: function () { var win = this.getformwindow(); win.settitle('add book'); win.setaction('add'); win.down('form').getform().reset(); win.show(); }, doaddbook: function () { var win = this.getformwindow(); var store = this.getbooksstore(); var values = win.down('form').getvalues(); var action = win.getaction(); // var book = ext.create('techzoo.model.book', values); var url = ''; if(action == 'edit') { url = '/springmvc-extjs-crud/api/book/updatebook'; } else { url = '/springmvc-extjs-crud/api/book/save'; } ext.ajax.request({ url: url, method : 'post', jsondata: values, success: function(response){ store.load(); } }); win.close(); } }); ext.application({ name : 'techzoo', controllers: ['books'], launch: function () { ext.widget('bookslist', { width : 500, height: 300, renderto: 'output' }); } } ); }); output: open the html file in any browser, the output will look similar to below. you can click to add new book record in grid.

I've begun work on trying to answer the questions I gathered concerning Cordova's FileSystem support. As I work through the questions I'm trying to build "real" samples to go along with the text. My first sample is a simple one, but I think it is pretty relevant for the types of things folks may do with Cordova and the file system - checking to see if a file exists locally and if not - fetching it. I'll begin by sharing the code and then explaining the parts. Here is the entire JavaScript file for the application. (Earlier today, Andrew Grieve shared a way my code could be simplified by a good 1/3rd. The code below reflects his update and has been changed since my original writing of the blog post.) document.addEventListener("deviceready", init, false); //The directory to store data var store; //Used for status updates var $status; //URL of our asset var assetURL = "https://raw.githubusercontent.com/cfjedimaster/Cordova-Examples/master/readme.md"; //File name of our important data file we didn't ship with the app var fileName = "mydatafile.txt"; function init() { $status = document.querySelector("#status"); $status.innerHTML = "Checking for data file."; store = cordova.file.dataDirectory; //Check for the file. window.resolveLocalFileSystemURL(store + fileName, appStart, downloadAsset); } function downloadAsset() { var fileTransfer = new FileTransfer(); console.log("About to start transfer"); fileTransfer.download(assetURL, store + fileName, function(entry) { console.log("Success!"); appStart(); }, function(err) { console.log("Error"); console.dir(err); }); } //I'm only called when the file exists or has been downloaded. function appStart() { $status.innerHTML = "App ready!"; } Ok, let's break it down. The first step is to check to see if our file exists already. The question is - where should we store the file? If you look at the docs for the FileSystem, you will see that the latest version of the plugin adds some useful aliases for common folders. Unfortunately, the docs are not exactly clear about how some of these aliases work. I asked for help (both on the PhoneGap Google group and the Cordova development list) and got some good responses from Kerri Shotts and Julio Sanchez. The directory that I thought made sense, cordova.file.applicationStorageDirectory, is incorrectly documented as being writeable in iOS. A pull request has already been filed to fix this mistake. For my application, the most appropriate directory is the next one, cordova.file.dataDirectory. Once I have my directory alias, I can make use of resolveLocalFileSystem on the directory plus desired file name to see if it exists. The third argument, downloadAsset, will only be run on an error, in this case a file not existing. If the file does not exist, we then have to download it. For this we use a second plugin, FileTransfer. This is where one more point of confusion comes in. We need to convert that earlier DirectoryEntry object, the one we used to get an API for files and directories, back to a URL so we can give a path to the Download API. So to recap - we've got a few moving parts here. We've got a directory alias, built into the plugin for easily finding common folders for our application. Again, the docs here are currently a bit wrong but they should be corrected soon. From that we can quickly see if our desired file exists, and if not, use the FileTransfer plugin to download it. Simple... but even a simple application caused me a bit of trouble, so hopefully this helps others. You can get the full source code here: https://github.com/cfjedimaster/Cordova-Examples/tree/master/checkanddownload

Spring Security offers an authentication replacement feature, often referred to as Run-As, that can replace the current user's authentication (and thus permissions) during a single secured object invocation. Using this feature makes sense when a backend system invoked during request processing requires different privileges than the current application. For example, an application might want to expose a financial transaction log to the currently logged in user, but the backend system that provides it only permits this action to the members of a special "auditor" role. The application can not simply assign this role to the user as that would potentially permit them to execute other restricted actions. Instead, the user can be given this right exclusively for viewing their transaction log. Only two classes are used to implement this feature. Instances of RunAsManager are tasked with producing the actual replacement authentication tokens. A sensible default implementation is already provided by Spring Security. As with other types of authentication, it is also necessary to register an instance of an appropriate AuthenticationProvider. Tokens produced by runAsManager are signed with the provided key (my_run_as_key in the example above) and are later checked against the same key by runAsAuthenticationProvider, in order to mitigate the risk of fake tokens being provided. These keys can have any value, but need to be the same in both objects. Otherwise, runAsAuthenticationProvider will reject the produced tokens as invalid. If an instance is registered, RunAsManager will be invoked by AbstractSecurityInterceptor for every intercepted object invocation for which the user has already been given access. If RunAsManager returns a token, this token will be used be used instead of the original one for the duration of the invocation, thus granting the user different privileges. There are two key points here. In order for the authentication replacement feature to do anything, the call has to actually be secured (and thus intercepted), and the user has to already have been granted access. To register a RunAsManager instance with the method security interceptor, something similar to the following is needed: Now, all methods secured by the @Secured annotation will be able to trigger RunAsManager. One important point here is that global-method-security will only work in the Spring context in which it is defined. In Spring MVC applications, there usually are two Spring contexts: the parent context, attached to ContextLoaderListener, and the child context, attached toDispatcherServlet. To secure Controller methods in this way, global-method-security must be added to DispatcherServlet's context. To secure methods in beans not in this context, global-method-security should also be added to ContextLoaderListener's context. Otherwise, security annotations will be ignored. The default implementation of RunAsManager (RunAsManagerImpl) will inspect the secured object's configuration and if it finds any attributes prefixed with RUN_AS_, it will create a token identical to the original, with the addition of one new GrantedAuthorty per RUN_AS_ attribute found. The new GrantedAuthority will be a role (prefixed by ROLE_ by default) named like the found attribute without the RUN_AS_ prefix. So, if a user with a role ROLE_REGISTERED_USER invokes a method annotated with @Secured({"ROLE_REGISTERED_USER","RUN_AS_AUDITOR"}), e.g. @Controller public class TransactionLogController { @Secured({"ROLE_REGISTERED_USER","RUN_AS_AUDITOR"}) //Authorities needed for method access and authorities added by RunAsManager prefixed with RUN_AS_ @RequestMapping(value = "/transactions", method = RequestMethod.GET) //Spring MVC configuration. Not related to security @ResponseBody //Spring MVC configuration. Not related to security public List getTransactionLog(...) { ... //Invoke something in the backend requiring ROLE_AUDITOR { ... //User does not have ROLE_AUDITOR here } the resulting token created by RunAsManagerImpl with be granted ROLE_REGISTERED_USER and ROLE_AUDITOR. Thus, the user will also be allowed actions, normally reserved for ROLE_AUDITOR members, during the current invocation, permitting them, in this case, to access the transaction log.To enable runAsAuthenticationProvider, register it as usual: ... other authentication-providers used by the application ... This is all that is necessary to have the default implementation activated. Still, this setting will not work for methods secured by @PreAuthorize and @PostAuthorize annotations as their configuration attributes are differently evaluated (they are SpEL expressions and not a simple list or required authorities like with @Secured) and will not be recognized by RunAsManagerImpl. For this scenario to work, a custom RunAsManager implementation is required, as, at least at the time of writing, no applicable implementation is provided by Spring. A custom RunAsManager implementation for use with @PreAuthorize/@PostAuthorize A convenient implementation relying on a custom annotation is provided below: public class AnnotationDrivenRunAsManager extends RunAsManagerImpl { @Override public Authentication buildRunAs(Authentication authentication, Object object, Collection attributes) { if(!(object instanceof ReflectiveMethodInvocation) || ((ReflectiveMethodInvocation)object).getMethod().getAnnotation(RunAsRole.class) == null) { return super.buildRunAs(authentication, object, attributes); } String roleName = ((ReflectiveMethodInvocation)object).getMethod().getAnnotation(RunAsRole.class).value(); if (roleName == null || roleName.isEmpty()) { return null; } GrantedAuthority runAsAuthority = new SimpleGrantedAuthority(roleName); List newAuthorities = new ArrayList(); // Add existing authorities newAuthorities.addAll(authentication.getAuthorities()); // Add the new run-as authority newAuthorities.add(runAsAuthority); return new RunAsUserToken(getKey(), authentication.getPrincipal(), authentication.getCredentials(), newAuthorities, authentication.getClass()); } } This implementation will look for a custom @RunAsRole annotation on a protected method (e.g. @RunAsRole("ROLE_AUDITOR")) and, if found, will add the given authority (ROLE_AUDITOR in this case) to the list of granted authorities. RunAsRole itself is just a simple custom annotation: @Retention(RetentionPolicy.RUNTIME) @Target(ElementType.METHOD) public @interface RunAsRole { String value(); } This new implementation would be instantiated in the same way as before: And registered in a similar fashion: The expression-handler is always required for pre-post-annotations to work. It is a part of the standard Spring Security configuration, and not related to the topic described here. Both pre-post-annotations and secured-annotations can be enabled at the same time, but should never be used in the same class. The protected controller method from above could now look like this: @Controller public class TransactionLogController { @PreAuthorize("hasRole('ROLE_REGISTERED_USER')") //Authority needed to access the method @RunAsRole("ROLE_AUDITOR") //Authority added by RunAsManager @RequestMapping(value = "/transactions", method = RequestMethod.GET) //Spring MVC configuration. Not related to security @ResponseBody //Spring MVC configuration. Not related to security public List getTransactionLog(...) { ... //Invoke something in the backend requiring ROLE_AUDITOR { ... //User does not have ROLE_AUDITOR here }