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.contrib.components;
016
017import org.apache.tapestry.IRender;
018import org.apache.tapestry.IRequestCycle;
019import org.apache.tapestry.components.Conditional;
020
021/**
022 *  This component is a container for {@link When} or Otherwise components;
023 *  it provides the context for mutually exclusive conditional evaluation.
024 *
025 *  [<a href="../../../../../../ComponentReference/contrib.Choose.html">Component Reference</a>]
026 *
027 *  @author David Solis
028 * 
029 */
030public abstract class Choose extends Conditional {
031
032
033        public void addBody(IRender element)
034        {
035                super.addBody(element);
036                if (element instanceof When)
037                        ((When) element).setChoose(this);       
038        }
039        
040        protected void cleanupAfterRender(IRequestCycle cycle)
041        {
042                setConditionMet(false);
043                super.cleanupAfterRender(cycle);
044        }
045        
046        protected boolean evaluateCondition()
047        {
048                return getCondition();
049        }
050
051        public boolean getInvert()
052        {
053                // This component doesn't require invert parameter.
054                return false;
055        }
056
057        public abstract boolean getCondition();
058        
059        public abstract boolean isConditionMet();
060        public abstract void setConditionMet(boolean value);
061}