001    /**
002     * Copyright (c) 2000-2013 Liferay, Inc. All rights reserved.
003     *
004     * This library is free software; you can redistribute it and/or modify it under
005     * the terms of the GNU Lesser General Public License as published by the Free
006     * Software Foundation; either version 2.1 of the License, or (at your option)
007     * any later version.
008     *
009     * This library is distributed in the hope that it will be useful, but WITHOUT
010     * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
011     * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
012     * details.
013     */
014    
015    package com.liferay.taglib.core;
016    
017    import com.liferay.portal.kernel.servlet.taglib.TagSupport;
018    
019    /**
020     * @author Shuyang Zhou
021     */
022    public class ChooseTag extends TagSupport {
023    
024            public boolean canRun() {
025                    return !_ran;
026            }
027    
028            @Override
029            public int doStartTag() {
030                    _ran = false;
031    
032                    return EVAL_BODY_INCLUDE;
033            }
034    
035            public void markRan() {
036                    if (_ran) {
037                            throw new IllegalStateException("Another subtag has already run");
038                    }
039    
040                    _ran = true;
041            }
042    
043            @Override
044            public void release() {
045                    super.release();
046    
047                    _ran = false;
048            }
049    
050            private boolean _ran;
051    
052    }