package bboss.org.apache.velocity.app.event;
/*
* 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.
*/
import bboss.org.apache.velocity.context.Context;
import bboss.org.apache.velocity.util.ContextAware;
/**
* Reference 'Stream insertion' event handler. Called with object
* that will be inserted into stream via value.toString().
*
* Please return an Object that will toString() nicely :)
*
* @author <a href="mailto:wglass@forio.com">Will Glass-Husain</a>
* @author <a href="mailto:geirm@optonline.net">Geir Magnusson Jr.</a>
* @version $Id: ReferenceInsertionEventHandler.java 685685 2008-08-13 21:43:27Z nbubna $
*/
public interface ReferenceInsertionEventHandler extends EventHandler
{
/**
* A call-back which is executed during Velocity merge before a reference
* value is inserted into the output stream. All registered
* ReferenceInsertionEventHandlers are called in sequence. If no
* ReferenceInsertionEventHandlers are are registered then reference value
* is inserted into the output stream as is.
*
* @param reference Reference from template about to be inserted.
* @param value Value about to be inserted (after its <code>toString()</code>
* method is called).
* @return Object on which <code>toString()</code> should be called for
* output.
*/
public Object referenceInsert( String reference, Object value );
/**
* Defines the execution strategy for referenceInsert
* @since 1.5
*/
static class referenceInsertExecutor implements EventHandlerMethodExecutor
{
private Context context;
private String reference;
private Object value;
referenceInsertExecutor(
Context context,
String reference,
Object value)
{
this.context = context;
this.reference = reference;
this.value = value;
}
/**
* Call the method referenceInsert()
*
* @param handler call the appropriate method on this handler
*/
public void execute(EventHandler handler)
{
ReferenceInsertionEventHandler eh = (ReferenceInsertionEventHandler) handler;
if (eh instanceof ContextAware)
((ContextAware) eh).setContext(context);
/**
* Every successive call will alter the same value
*/
value = ((ReferenceInsertionEventHandler) handler).referenceInsert(reference, value);
}
public Object getReturnValue()
{
return value;
}
/**
* Continue to end of event handler iteration
*
* @return always returns false
*/
public boolean isDone()
{
return false;
}
}
}