1 /** 2 * This file Copyright (c) 2003-2010 Magnolia International 3 * Ltd. (http://www.magnolia-cms.com). All rights reserved. 4 * 5 * 6 * This file is dual-licensed under both the Magnolia 7 * Network Agreement and the GNU General Public License. 8 * You may elect to use one or the other of these licenses. 9 * 10 * This file is distributed in the hope that it will be 11 * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the 12 * implied warranty of MERCHANTABILITY or FITNESS FOR A 13 * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT. 14 * Redistribution, except as permitted by whichever of the GPL 15 * or MNA you select, is prohibited. 16 * 17 * 1. For the GPL license (GPL), you can redistribute and/or 18 * modify this file under the terms of the GNU General 19 * Public License, Version 3, as published by the Free Software 20 * Foundation. You should have received a copy of the GNU 21 * General Public License, Version 3 along with this program; 22 * if not, write to the Free Software Foundation, Inc., 51 23 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 24 * 25 * 2. For the Magnolia Network Agreement (MNA), this file 26 * and the accompanying materials are made available under the 27 * terms of the MNA which accompanies this distribution, and 28 * is available at http://www.magnolia-cms.com/mna.html 29 * 30 * Any modifications to this file must keep this entire header 31 * intact. 32 * 33 */ 34 package info.magnolia.cms.taglibs; 35 36 import javax.servlet.jsp.JspException; 37 import javax.servlet.jsp.JspTagException; 38 39 import org.slf4j.Logger; 40 import org.slf4j.LoggerFactory; 41 42 /** 43 * @author philipp 44 * @version $Id: BaseConditionalContentTag.java 32667 2010-03-13 00:37:06Z gjoseph $ 45 * 46 */ 47 public abstract class BaseConditionalContentTag extends BaseContentTag { 48 49 /** 50 * <p>Subclasses implement this method to compute the boolean result 51 * of the conditional action. This method is invoked once per tag invocation 52 * by <tt>doStartTag()</tt>. 53 * 54 * @return a boolean representing the condition that a particular subclass 55 * uses to drive its conditional logic. 56 */ 57 protected abstract boolean condition() throws JspTagException; 58 59 /** 60 * Includes its body if <tt>condition()</tt> evaluates to true. 61 */ 62 public int doStartTag() throws JspException { 63 64 // execute our condition() method once per invocation 65 boolean result = condition(); 66 67 // handle conditional behavior 68 if (result) 69 return EVAL_BODY_INCLUDE; 70 else 71 return SKIP_BODY; 72 } 73 74 }