001// Copyright 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.services.impl;
016
017import java.io.IOException;
018import java.io.Serializable;
019
020import org.apache.hivemind.util.Defense;
021import org.apache.tapestry.IRequestCycle;
022import org.apache.tapestry.engine.IEngineService;
023import org.apache.tapestry.engine.ILink;
024
025/**
026 * Inner proxy that actually resolves the engine service using the
027 * {@link org.apache.tapestry.services.impl.EngineServiceSource}, then replaces itself in the outer
028 * proxy.
029 * 
030 * @author Howard M. Lewis Ship
031 * @since 4.0
032 * @see org.apache.tapestry.services.impl.EngineServiceOuterProxy
033 */
034public class EngineServiceInnerProxy implements IEngineService, Serializable
035{
036    private static final long serialVersionUID = -8128030027597659447L;
037
038    private final String _serviceName;
039
040    private final EngineServiceOuterProxy _outerProxy;
041
042    private final EngineServiceSource _source;
043
044    public EngineServiceInnerProxy(String serviceName, EngineServiceOuterProxy outerProxy,
045            EngineServiceSource source)
046    {
047        Defense.notNull(serviceName, "serviceName");
048        Defense.notNull(outerProxy, "outerProxy");
049        Defense.notNull(source, "source");
050
051        _serviceName = serviceName;
052        _outerProxy = outerProxy;
053        _source = source;
054    }
055
056    public String toString()
057    {
058        return ImplMessages.engineServiceInnerProxyToString(_serviceName);
059    }
060
061    private IEngineService resolve()
062    {
063        IEngineService service = _source.resolveEngineService(_serviceName);
064
065        _outerProxy.installDelegate(service);
066
067        return service;
068    }
069
070    public synchronized ILink getLink(boolean post, Object parameter)
071    {
072        return resolve().getLink(post, parameter);
073    }
074
075    public synchronized void service(IRequestCycle cycle) throws IOException
076    {
077        resolve().service(cycle);
078    }
079
080    public String getName()
081    {
082        return _serviceName;
083    }
084
085}