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    
015    package org.apache.tapestry.binding;
016    
017    import org.apache.hivemind.Location;
018    import org.apache.hivemind.util.Defense;
019    import org.apache.tapestry.BindingException;
020    import org.apache.tapestry.IActionListener;
021    import org.apache.tapestry.IComponent;
022    import org.apache.tapestry.IRequestCycle;
023    import org.apache.tapestry.PageRedirectException;
024    import org.apache.tapestry.RedirectException;
025    import org.apache.tapestry.coerce.ValueConverter;
026    
027    /**
028     * @author Howard M. Lewis Ship
029     * @since 4.0
030     */
031    public 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    }