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deltaspike-exception-handling: An example how to use DeltaSpike exception handling

What is it?

This quickstart demonstrates exception handling with Java EE and CDI using the DeltaSpike library. Exception handling is based around the CDI eventing model.

The entire exception handling process starts with an event. This means your application is not tightly coupled to DeltaSpike, and allows for further extension. Exception handling in DeltaSpike aims to keep out of your way, and let you handle exceptions the way that makes the most sense to you. The eventing model allows for this delicate balance; firing an event is the main way to start handling an exception.

The quickstart can be told to throw two Exceptions: MyException and MyOtherException. And there are 4 different handlers:

  • FacesExceptionHandler - Displays each exception on the page using a Faces. Only handles @FacesRequest exceptions.
  • LogExceptionHandler - Logs each exception to the server console.
  • MyExceptionCountHandler - Counts the the number of times MyException is thrown. This handler is also a CDI bean with a name.
  • RestExceptionHandler - Produces a javax.ws.rs.core.Response which encapsulates the error, using a ResponseBuilder. Only handles @RestRequest exceptions.

Any exceptions from the REST endpoint are passed to the DeltaSpikeExceptionMapper (a JAX-RS exception mapper), which fires an exception event, which is observed by all relevant exception handlers. Of particular interest is the RestExceptionHandler which uses the ResponseBuilderProducer to create a instance of a javax.ws.rs.core.Response. The built response is then returned to the client by the RestExceptionMapper.

Any exceptions from beans invoked by JSF are passed to the DeltaSpikeExceptionHandler which fires an exception event, which is observed by all relevant exception handlers. Of particular interest is the FacesExceptionHandler which builds and registers some FacesMessages.

System requirements

The application this project produces is designed to be run on Red Hat JBoss Enterprise Application Platform (EAP) 6.1 or later with the Red Hat JBoss Web Framework Kit (WFK) 2.6.

All you need to build this project is Java 6.0 (Java SDK 1.6) or later, Maven 3.0 or later.

Configure Maven

If you have not yet done so, you must Configure Maven before testing the quickstarts.

Start the JBoss EAP Server

  1. Open a command line and navigate to the root of the JBoss EAP directory.
  2. The following shows the command line to start the server with the default profile:

     For Linux:   EAP_HOME/bin/standalone.sh
     For Windows: EAP_HOME\bin\standalone.bat
    

Build and Deploy the Quickstart

NOTE: The following build command assumes you have configured your Maven user settings. If you have not, you must include Maven setting arguments on the command line. See Build and Deploy the Quickstarts for complete instructions and additional options.

  1. Make sure you have started the JBoss EAP server as described above.
  2. Open a command line and navigate to the root directory of this quickstart.
  3. Type this command to build and deploy the archive:

     mvn clean package jboss-as:deploy
    
  4. This will deploy target/jboss-deltaspike-exception-handling.war to the running instance of the server.

Access the application

Access the running application in a browser at the following URL: http://localhost:8080/jboss-deltaspike-exception-handling

You will be presented with a form that contains two buttons. One button throws the exception MyException. The other button throws the exception MyOtherException.

When you click on a button, a message is displayed showing the exception message followed by the number of times the service was invoked. Notice that the MyException counter is only incremented when MyException is thrown. You can also view the exception messages in the server log.

Click on REST Invocation Test link. The rest response is displayed on the iframe bellow.

Undeploy the Archive

  1. Make sure you have started the JBoss EAP server as described above.
  2. Open a command line and navigate to the root directory of this quickstart.
  3. When you are finished testing, type this command to undeploy the archive:

     mvn jboss-as:undeploy
    

Run the Arquillian Functional Tests

This quickstart provides Arquillian functional tests. They are located under the directory "functional-tests". Functional tests verify that your application behaves correctly from the user's point of view - simulating clicking around the page as a normal user would do.

To run these tests, you must build the main project as described above.

  1. Open a command line and navigate to the root directory of this quickstart.
  2. Build the quickstart WAR using the following command:

     mvn clean package
    
  3. Navigate to the functional-tests/ directory in this quickstart.
  4. If you have a running instance of the JBoss EAP server, as described above, run the remote tests by typing the following command:

     mvn clean verify -Parq-jbossas-remote
    
  5. If you prefer to run the functional tests using managed instance of the JBoss EAP server, meaning the tests will start the server for you, type the following command:

NOTE: For this to work, Arquillian needs to know the location of the JBoss EAP server. This can be declared through the JBOSS_HOME environment variable or the jbossHome property in arquillian.xml. See Run the Arquillian Tests for complete instructions and additional options.

    mvn clean verify -Parq-jbossas-managed

Run the Quickstart in JBoss Developer Studio or Eclipse

You can also start the server and deploy the quickstarts from Eclipse using JBoss tools. For more information, see Use JBoss Developer Studio or Eclipse to Run the Quickstarts

Debug the Application

If you want to debug the source code or look at the Javadocs of any library in the project, run either of the following commands to pull them into your local repository. The IDE should then detect them.

mvn dependency:sources
mvn dependency:resolve -Dclassifier=javadoc

Recent Changelog

  • May 29, 2014(Emil Cervenan):Squashed README files update. WFK 2.5 version replaced with 2.6
  • May 14, 2014(Marek Novotný):updated README.md info about WFK 2.6
  • Mar 27, 2014(Sande Gilda):WFK2 555 Replace JBOSS_HOME with EAP_HOME
  • Feb 28, 2014(Sande Gilda):Edits to README files to render metadata correctly and to use the correct term for JBoss EAP
  • Feb 17, 2014(Sande Gilda):JDF 614 Update WFK version from 2.4 to 2.5
  • Oct 4, 2013(Ron Smeral):Added note about JBOSS_HOME configuration for arq managed container typo fix
  • Sep 23, 2013(Ron Smeral):Updated READMEs for functional tests of DeltaSpike QS
  • Oct 2, 2013(Sande Gilda):JDF 503 Remove AS 7 references add versions general cleanup remove temp repo from settings
  • Sep 23, 2013(Sande Gilda):Update metadata source URLs to new repository
  • Sep 13, 2013(Sande Gilda):JDF 487 Remove as from quickstart artifactId and archive names and access URLs in README files
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