1 /* 2 * $Id: ELMatchSupport.java 471754 2006-11-06 14:55:09Z husted $ 3 * 4 * Licensed to the Apache Software Foundation (ASF) under one 5 * or more contributor license agreements. See the NOTICE file 6 * distributed with this work for additional information 7 * regarding copyright ownership. The ASF licenses this file 8 * to you under the Apache License, Version 2.0 (the 9 * "License"); you may not use this file except in compliance 10 * with the License. You may obtain a copy of the License at 11 * 12 * http://www.apache.org/licenses/LICENSE-2.0 13 * 14 * Unless required by applicable law or agreed to in writing, 15 * software distributed under the License is distributed on an 16 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 17 * KIND, either express or implied. See the License for the 18 * specific language governing permissions and limitations 19 * under the License. 20 */ 21 package org.apache.strutsel.taglib.logic; 22 23 import org.apache.struts.taglib.TagUtils; 24 import org.apache.struts.util.MessageResources; 25 26 import javax.servlet.jsp.JspException; 27 import javax.servlet.jsp.PageContext; 28 29 /** 30 * This class is used as a helper class for both the <code>org.apache.strutsel.taglib.logic.ELMatchTag</code> 31 * and <code>org.apache.strutsel.taglib.logic.ELNotMatchTag</code> classes. 32 * It's <code>condition</code> method encapsulates the common logic needed to 33 * examine the <code>location</code> attribute to determine how to do the 34 * comparison. 35 */ 36 class ELMatchSupport { 37 /** 38 * Performs a comparison of an expression and a value, with an optional 39 * location specifier in the expression (start or end). 40 * 41 * @param desired Indication of whether the "truth" value of the 42 * comparison is whether the expression and value are 43 * equal, or not equal. 44 * @param expr Expression to test against a value. 45 * @param value Value to test against an expression. 46 * @param location if set, is "start" or "end" to indicate to look at 47 * the start or end of the expression for the value. 48 * If null, look anywhere in the expression. 49 * @param messages <code>MessageResources</code> object to reference 50 * for error message text. 51 * @param pageContext used to save exception information, if needed. 52 * @return true if comparison result equals desired value, false 53 * otherwise. 54 */ 55 public static boolean condition(boolean desired, String expr, String value, 56 String location, MessageResources messages, PageContext pageContext) 57 throws JspException { 58 boolean result = false; 59 60 if (expr != null) { 61 // Perform the comparison requested by the location attribute 62 boolean matched = false; 63 64 if (location == null) { 65 matched = (expr.indexOf(value) >= 0); 66 } else if (location.equals("start")) { 67 matched = expr.startsWith(value); 68 } else if (location.equals("end")) { 69 matched = expr.endsWith(value); 70 } else { 71 JspException e = 72 new JspException(messages.getMessage("logic.location", 73 location)); 74 75 TagUtils.getInstance().saveException(pageContext, e); 76 throw e; 77 } 78 79 result = (matched == desired); 80 } 81 82 return (result); 83 } 84 }