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
015package org.apache.tapestry5.internal.transform;
016
017import org.apache.tapestry5.ComponentResources;
018import org.apache.tapestry5.plastic.FieldConduit;
019import 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 */
027public 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}