001// Copyright 2004, 2005 The Apache Software Foundation
002//
003// Licensed under the Apache License, Version 2.0 (the "License");
004// you may not use this file except in compliance with the License.
005// You may obtain a copy of the License at
006//
007//     http://www.apache.org/licenses/LICENSE-2.0
008//
009// Unless required by applicable law or agreed to in writing, software
010// distributed under the License is distributed on an "AS IS" BASIS,
011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012// See the License for the specific language governing permissions and
013// limitations under the License.
014
015package org.apache.tapestry.binding;
016
017import org.apache.hivemind.Location;
018import org.apache.hivemind.util.Defense;
019import org.apache.tapestry.BindingException;
020import org.apache.tapestry.IActionListener;
021import org.apache.tapestry.IComponent;
022import org.apache.tapestry.IRequestCycle;
023import org.apache.tapestry.PageRedirectException;
024import org.apache.tapestry.RedirectException;
025import org.apache.tapestry.coerce.ValueConverter;
026
027/**
028 * @author Howard M. Lewis Ship
029 * @since 4.0
030 */
031public class ListenerMethodBinding extends AbstractBinding implements IActionListener
032{
033    private final IComponent _component;
034
035    private final String _methodName;
036
037    // We have to defer obtaining the listener until after the page is loaded, because it is
038    // (currently) reliant on the page's engine property to gain access to the
039    // ListenerMapSource. I'd prefer it if this was a final field, resolved by the constructor,
040    // but that will involve injecting the ListenerMapSource into AbstractComponent.
041
042    private IActionListener _listener;
043
044    public ListenerMethodBinding(String description, ValueConverter valueConverter, Location location,
045            IComponent component, String methodName)
046    {
047        super(description, valueConverter, location);
048
049        Defense.notNull(component, "component");
050        Defense.notNull(methodName, "methodName");
051
052        _component = component;
053        _methodName = methodName;
054    }
055
056    public Object getComponent()
057    {
058        return _component;
059    }
060
061    /**
062     * Returns this binding object; the binding object delegates to the actual listener. This allows
063     * us to intercept errors and report the location of the binding.
064     */
065    public Object getObject()
066    {
067        return this;
068    }
069
070    public void actionTriggered(IComponent component, IRequestCycle cycle)
071    {
072        try
073        {
074            if (_listener == null)
075                _listener = _component.getListeners().getListener(_methodName);
076
077            _listener.actionTriggered(component, cycle);
078        }
079        catch (PageRedirectException ex)
080        {
081            throw ex;
082        }
083        catch (RedirectException ex)
084        {
085            throw ex;
086        }
087        catch (RuntimeException ex)
088        {
089            throw new BindingException(BindingMessages.listenerMethodFailure(
090                    _component,
091                    _methodName,
092                    ex), _component, getLocation(), this, ex);
093        }
094    }
095
096    protected void extendDescription(StringBuffer buffer)
097    {
098        buffer.append(", component=");
099        buffer.append(_component.getExtendedId());
100        buffer.append(", methodName=");
101        buffer.append(_methodName);
102    }
103
104}