Package org.zkoss.zkplus.jpa

Class OpenEntityManagerInViewListener

java.lang.Object

org.zkoss.zkplus.jpa.OpenEntityManagerInViewListener

All Implemented Interfaces:

ExecutionCleanup, ExecutionInit

public class OpenEntityManagerInViewListener
extends java.lang.Object
implements ExecutionCleanup, ExecutionInit

Listener to init and cleanup the JPA entityManager automatically

In WEB-INF/zk.xml, add following lines:

        <listener>
                <description>Hibernate "OpenEntityManagerInView" Listener</description>
                <listener-class>org.zkoss.zkplus.jpa.OpenEntityManagerInViewListener</listener-class>
        </listener>
 

Applicable to EJB version 3.2.ga or later

Since:

3.0.2

Author:

Jeff

Constructor Summary

Constructors

Constructor	Description
OpenEntityManagerInViewListener()

Method Summary

Modifier and Type	Method	Description
void	cleanup(Execution exec, Execution parent, java.util.List errs)	called when an execution is about to be destroyed.
protected void	handleException(Execution exec, java.lang.Throwable ex)	Default exception handler.
void	init(Execution exec, Execution parent)	Called when an execution is created and initialized.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

OpenEntityManagerInViewListener

public OpenEntityManagerInViewListener()

Method Detail

cleanup

public void cleanup(Execution exec,
                    Execution parent,
                    java.util.List errs)
             throws java.lang.Exception

Description copied from interface: ExecutionCleanup

called when an execution is about to be destroyed.

If this method throws an exception, the stack trace will be logged, and the error message will be displayed at the client.

When this method is invoked, the execution is still activated, so you can create components here.

Specified by:

cleanup in interface ExecutionCleanup

Parameters:

exec - the execution to clean up.

parent - the previous execution, or null if no previous at all

errs - a list of exceptions (java.lang.Throwable) if any exception occurred before this method is called, or null if no exception at all. Note: you can manipulate the list directly to add or clean up exceptions. For example, if exceptions are fixed correctly, you can call errs.clear() such that no error message will be displayed at the client.

Throws:

java.lang.Exception

init

public void init(Execution exec,
                 Execution parent)
          throws java.lang.Exception

Description copied from interface: ExecutionInit

Called when an execution is created and initialized.

Note: this method is called after exec is activated. In other words, Executions.getCurrent() is the same as the exec argument.

When this method is called, you can retrieve the current page with ExecutionCtrl.getCurrentPage(). However, the page is not initialized yet. In other words, Page.getDesktop(), Page.getId() and Page.getTitle() all return null. To get the current desktop, you have to use Execution.getDesktop() (from Executions.getCurrent()) instead. On the other hand, you can set the page's ID, title or style in this method (to override the declarations in the page definition) by Page.setId(java.lang.String), Page.setTitle(java.lang.String) and Page.setStyle(java.lang.String). In additions, Page.getRequestPath() and Page.getAttribute(java.lang.String, int) are all available.

Specified by:

init in interface ExecutionInit

Parameters:

exec - the execution being created.

parent - the previous execution in the same (Servlet) request, or null if this is the first execution of the request.

Throws:

java.lang.Exception

handleException

protected void handleException(Execution exec,
                               java.lang.Throwable ex)

Default exception handler. This implementation simply rollback the transaction.

Application developer might want to extends this class and override this method to do other things like compensate for any permanent changes during the conversation, and finally restart business conversation... what can be done here depends on the applications design.

Parameters:

exec - the execution to clean up.

ex - the Throwable which is not handled during the execution