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
015package org.apache.tapestry.binding;
016
017import org.apache.hivemind.Location;
018import org.apache.hivemind.util.Defense;
019import org.apache.tapestry.IComponent;
020import org.apache.tapestry.coerce.ValueConverter;
021
022/**
023 * A binding that connects directly to a localized string for a component.
024 * <p>
025 * Note: Renamed from StringBinding to MessageBinding in release 4.0.
026 * 
027 * @see IComponent#getString(String)
028 * @author Howard Lewis Ship
029 * @since 2.0.4
030 */
031
032public class MessageBinding extends AbstractBinding
033{
034    private final IComponent _component;
035
036    private final String _key;
037
038    protected MessageBinding(String description, ValueConverter valueConverter, Location location,
039            IComponent component, String key)
040    {
041        super(description, valueConverter, location);
042
043        Defense.notNull(component, "component");
044        Defense.notNull(key, "key");
045
046        _component = component;
047        _key = key;
048    }
049
050    public Object getComponent()
051    {
052        return _component;
053    }
054
055    public String getKey()
056    {
057        return _key;
058    }
059
060    /**
061     * Accesses the specified localized string. Never returns null.
062     */
063
064    public Object getObject()
065    {
066        return _component.getMessages().getMessage(_key);
067    }
068
069    public String toString()
070    {
071        StringBuffer buffer = new StringBuffer("StringBinding");
072        buffer.append('[');
073        buffer.append(_component.getExtendedId());
074        buffer.append(' ');
075        buffer.append(_key);
076        buffer.append(']');
077
078        return buffer.toString();
079    }
080}