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.components; 016 017import org.apache.tapestry.AbstractComponent; 018import org.apache.tapestry.IMarkupWriter; 019import org.apache.tapestry.IRender; 020import org.apache.tapestry.IRequestCycle; 021 022/** 023 * A component which delegates it's behavior to another object. 024 * 025 * [<a href="../../../../../ComponentReference/Delegator.html">Component Reference</a>] 026 * 027 * @author Howard Lewis Ship 028 * 029 **/ 030 031public abstract class Delegator extends AbstractComponent 032{ 033 /** 034 * Gets its delegate and invokes {@link IRender#render(IMarkupWriter, IRequestCycle)} 035 * on it. 036 * 037 **/ 038 039 protected void renderComponent(IMarkupWriter writer, IRequestCycle cycle) 040 { 041 IRender delegate = getDelegate(); 042 043 if (delegate != null) 044 delegate.render(writer, cycle); 045 } 046 047 public abstract IRender getDelegate(); 048}