1 /* 2 * $Id: ELMessagesNotPresentTag.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.logic.MessagesNotPresentTag; 24 import org.apache.strutsel.taglib.utils.EvalHelper; 25 26 import javax.servlet.jsp.JspException; 27 28 /** 29 * Evalute to <code>false</code> if an <code>ActionMessages</code> class or a 30 * class that can be converted to an <code>ActionMessages</code> class is in 31 * request scope under the specified key and there is at least one message in 32 * the class or for the property specified. <p> This class is a subclass of 33 * the class <code>org.apache.struts.taglib.logic.MessagesNotPresentTag</code> 34 * which provides most of the described functionality. This subclass allows 35 * all attribute values to be specified as expressions utilizing the 36 * JavaServer Pages Standard Library expression language. 37 * 38 * @version $Rev: 471754 $ 39 */ 40 public class ELMessagesNotPresentTag extends MessagesNotPresentTag { 41 /** 42 * Instance variable mapped to "name" tag attribute. (Mapping set in 43 * associated BeanInfo class.) 44 */ 45 private String nameExpr; 46 47 /** 48 * Instance variable mapped to "property" tag attribute. (Mapping set in 49 * associated BeanInfo class.) 50 */ 51 private String propertyExpr; 52 53 /** 54 * Instance variable mapped to "message" tag attribute. (Mapping set in 55 * associated BeanInfo class.) 56 */ 57 private String messageExpr; 58 59 /** 60 * Getter method for "name" tag attribute. (Mapping set in associated 61 * BeanInfo class.) 62 */ 63 public String getNameExpr() { 64 return (nameExpr); 65 } 66 67 /** 68 * Getter method for "property" tag attribute. (Mapping set in associated 69 * BeanInfo class.) 70 */ 71 public String getPropertyExpr() { 72 return (propertyExpr); 73 } 74 75 /** 76 * Getter method for "message" tag attribute. (Mapping set in associated 77 * BeanInfo class.) 78 */ 79 public String getMessageExpr() { 80 return (messageExpr); 81 } 82 83 /** 84 * Setter method for "name" tag attribute. (Mapping set in associated 85 * BeanInfo class.) 86 */ 87 public void setNameExpr(String nameExpr) { 88 this.nameExpr = nameExpr; 89 } 90 91 /** 92 * Setter method for "property" tag attribute. (Mapping set in associated 93 * BeanInfo class.) 94 */ 95 public void setPropertyExpr(String propertyExpr) { 96 this.propertyExpr = propertyExpr; 97 } 98 99 /** 100 * Setter method for "message" tag attribute. (Mapping set in associated 101 * BeanInfo class.) 102 */ 103 public void setMessageExpr(String messageExpr) { 104 this.messageExpr = messageExpr; 105 } 106 107 /** 108 * Releases state of custom tag so this instance can be reused. 109 */ 110 public void release() { 111 super.release(); 112 setNameExpr(null); 113 setPropertyExpr(null); 114 setMessageExpr(null); 115 } 116 117 /** 118 * Process the start tag. 119 * 120 * @throws JspException if a JSP exception has occurred 121 */ 122 public int doStartTag() throws JspException { 123 evaluateExpressions(); 124 125 return (super.doStartTag()); 126 } 127 128 /** 129 * Processes all attribute values which use the JSTL expression evaluation 130 * engine to determine their values. 131 * 132 * @throws JspException if a JSP exception has occurred 133 */ 134 private void evaluateExpressions() 135 throws JspException { 136 String string = null; 137 138 if ((string = 139 EvalHelper.evalString("name", getNameExpr(), this, pageContext)) != null) { 140 setName(string); 141 } 142 143 if ((string = 144 EvalHelper.evalString("property", getPropertyExpr(), this, 145 pageContext)) != null) { 146 setProperty(string); 147 } 148 149 if ((string = 150 EvalHelper.evalString("message", getMessageExpr(), this, 151 pageContext)) != null) { 152 setMessage(string); 153 } 154 } 155 }