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.*;
020    import org.apache.tapestry.coerce.ValueConverter;
021    
022    /**
023     * @author Howard M. Lewis Ship
024     * @since 4.0
025     */
026    public class ListenerMethodBinding extends AbstractBinding implements IActionListener
027    {
028        private final IComponent _component;
029    
030        private final String _methodName;
031    
032        // We have to defer obtaining the listener until after the page is loaded, because it is
033        // (currently) reliant on the page's engine property to gain access to the
034        // ListenerMapSource. I'd prefer it if this was a final field, resolved by the constructor,
035        // but that will involve injecting the ListenerMapSource into AbstractComponent.
036    
037        private IActionListener _listener;
038    
039        public ListenerMethodBinding(String description, ValueConverter valueConverter, Location location,
040                                     IComponent component, String methodName)
041        {
042            super(description, valueConverter, location);
043    
044            Defense.notNull(component, "component");
045            Defense.notNull(methodName, "methodName");
046    
047            _component = component;
048            _methodName = methodName;
049        }
050    
051        public Object getComponent()
052        {
053            return _component;
054        }
055    
056        /**
057         * Returns this binding object; the binding object delegates to the actual listener. This allows
058         * us to intercept errors and report the location of the binding.
059         */
060        public Object getObject()
061        {
062            return this;
063        }
064    
065        public String getMethodName()
066        {
067            return _methodName;
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 (RenderRewoundException ex)
088            {
089                throw ex;
090            }
091            catch (RuntimeException ex)
092            {
093                throw new BindingException(BindingMessages.listenerMethodFailure(
094                  _component,
095                  _methodName,
096                  ex), _component, getLocation(), this, ex);
097            }
098        }
099    
100        protected void extendDescription(StringBuffer buffer)
101        {
102            buffer.append(", component=");
103            buffer.append(_component.getExtendedId());
104            buffer.append(", methodName=");
105            buffer.append(_methodName);
106        }
107    }