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.ApplicationRuntimeException;
018    import org.apache.hivemind.Location;
019    import org.apache.hivemind.util.Defense;
020    import org.apache.tapestry.IComponent;
021    import org.apache.tapestry.coerce.ValueConverter;
022    
023    /**
024     * A binding where the path is the id of a child component.
025     * 
026     * @author Howard M. Lewis Ship
027     * @since 4.0
028     */
029    public class ComponentBinding extends AbstractBinding
030    {
031        private final IComponent _component;
032    
033        private final String _componentId;
034    
035        public ComponentBinding(String description, ValueConverter valueConverter, Location location,
036                IComponent component, String componentId)
037        {
038            super(description, valueConverter, location);
039    
040            Defense.notNull(component, "component");
041            Defense.notNull(componentId, "componentId");
042    
043            _component = component;
044            _componentId = componentId;
045        }
046    
047        public Object getObject()
048        {
049            try
050            {
051                return _component.getComponent(_componentId);
052            }
053            catch (Exception ex)
054            {
055                throw new ApplicationRuntimeException(ex.getMessage(), getLocation(), ex);
056            }
057        }
058    
059        public Object getComponent()
060        {
061            return _component;
062        }
063    
064    }