package bboss.org.apache.velocity.app.event;
import bboss.org.apache.velocity.context.Context;
import bboss.org.apache.velocity.util.ContextAware;
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
/**
* Event handler called when a method throws an exception. This gives the
* application a chance to deal with it and either
* return something nice, or throw.
*
* Please return what you want rendered into the output stream.
*
* @author <a href="mailto:wglass@forio.com">Will Glass-Husain</a>
* @author <a href="mailto:geirm@optonline.net">Geir Magnusson Jr.</a>
* @version $Id: MethodExceptionEventHandler.java 685685 2008-08-13 21:43:27Z nbubna $
*/
public interface MethodExceptionEventHandler extends EventHandler
{
/**
* Called when a method throws an exception.
* Only the first registered MethodExceptionEventHandler is called. If
* none are registered a MethodInvocationException is thrown.
*
* @param claz the class of the object the method is being applied to
* @param method the method
* @param e the thrown exception
* @return an object to insert in the page
* @throws Exception an exception to be thrown instead inserting an object
*/
public Object methodException( Class claz, String method, Exception e )
throws Exception;
/**
* Defines the execution strategy for methodException
* @since 1.5
*/
static class MethodExceptionExecutor implements EventHandlerMethodExecutor
{
private Context context;
private Class claz;
private String method;
private Exception e;
private Object result;
private boolean executed = false;
MethodExceptionExecutor(
Context context,
Class claz,
String method,
Exception e)
{
this.context = context;
this.claz = claz;
this.method = method;
this.e = e;
}
/**
* Call the method methodException()
*
* @param handler call the appropriate method on this handler
* @exception Exception generic exception thrown by methodException event handler method call
*/
public void execute(EventHandler handler) throws Exception
{
MethodExceptionEventHandler eh = (MethodExceptionEventHandler) handler;
if (eh instanceof ContextAware)
((ContextAware) eh).setContext(context);
executed = true;
result = ((MethodExceptionEventHandler) handler).methodException(claz, method, e);
}
public Object getReturnValue()
{
return result;
}
/**
* Only run the first MethodExceptionEventHandler
*
* @return true after this is executed once.
*/
public boolean isDone()
{
return executed;
}
}
}