tapestry/tapestry-framework/src/java/org/apache/tapestry/components/Delegator.java

// Copyright 2004, 2005 The Apache Software Foundation
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package org.apache.tapestry.components;

import org.apache.tapestry.AbstractComponent;
import org.apache.tapestry.IMarkupWriter;
import org.apache.tapestry.IRender;
import org.apache.tapestry.IRequestCycle;

/**
 * A component which delegates it's behavior to another object. [<a
 * href="../../../../../ComponentReference/Delegator.html">Component Reference</a>]
 * 
 * @author Howard Lewis Ship
 */

public abstract class Delegator extends AbstractComponent
{

    /**
     * Gets its delegate and invokes
     * {@link IRender#render(IMarkupWriter, IRequestCycle)} on it.
     */

    protected void renderComponent(IMarkupWriter writer, IRequestCycle cycle)
    {
        IRender delegate = getDelegate();
        
        if (delegate != null) delegate.render(writer, cycle);
    }

    public abstract IRender getDelegate();
}