// Copyright 2005 The Apache Software Foundation
//
// Licensed 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.
package org.apache.tapestry.listener;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import org.apache.hivemind.ApplicationRuntimeException;
import org.apache.hivemind.util.Defense;
import org.apache.tapestry.IActionListener;
/**
* @author Howard M. Lewis Ship
* @since 4.0
*/
public class ListenerMapImpl implements ListenerMap
{
private final Object _target;
/**
* Keyed on String method name, value is
* {@link org.apache.tapestry.listener.ListenerMethodInvoker}.
*/
private final Map _invokers;
private final Map _listeners = new HashMap();
public ListenerMapImpl(Object target, Map invokers)
{
Defense.notNull(target, "target");
Defense.notNull(invokers, "invokers");
_target = target;
_invokers = invokers;
}
public boolean canProvideListener(String name)
{
return _invokers.containsKey(name);
}
public synchronized IActionListener getListener(String name)
{
IActionListener result = (IActionListener) _listeners.get(name);
if (result == null)
{
result = createListener(name);
_listeners.put(name, result);
}
return result;
}
private IActionListener createListener(String name)
{
ListenerMethodInvoker invoker = (ListenerMethodInvoker) _invokers.get(name);
if (invoker == null)
throw new ApplicationRuntimeException(ListenerMessages.objectMissingMethod(
_target,
name), _target, null, null);
return new SyntheticListener(_target, invoker);
}
public Collection getListenerNames()
{
return Collections.unmodifiableCollection(_invokers.keySet());
}
}