001    // Copyright 2010, 2011 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.tapestry5.internal.transform;
016    
017    import org.apache.tapestry5.ComponentResources;
018    import org.apache.tapestry5.plastic.FieldConduit;
019    import org.apache.tapestry5.plastic.InstanceContext;
020    
021    /**
022     * An implementation of {@link FieldConduit} for a read-only component field. Subclasses
023     * provide an implementation of the {@link #get(Object, org.apache.tapestry5.plastic.InstanceContext)} method.
024     *
025     * @since 5.2.0
026     */
027    public abstract class ReadOnlyComponentFieldConduit implements FieldConduit<Object>
028    {
029        private final String qualifiedFieldName;
030    
031        public ReadOnlyComponentFieldConduit(String qualifiedFieldName)
032        {
033            this.qualifiedFieldName = qualifiedFieldName;
034        }
035    
036        public ReadOnlyComponentFieldConduit(String className, String fieldName)
037        {
038            this(String.format("%s.%s", className, fieldName));
039        }
040    
041        public ReadOnlyComponentFieldConduit(ComponentResources resources, String fieldName)
042        {
043            this(resources.getComponentModel().getComponentClassName(), fieldName);
044        }
045    
046        public void set(Object instance, InstanceContext context, Object newValue)
047        {
048            throw new RuntimeException(String.format("Field %s is read only.", qualifiedFieldName));
049        }
050    }