001 /* $Id: SetTopRule.java 729106 2008-12-23 20:48:09Z rahul $ 002 * 003 * Licensed to the Apache Software Foundation (ASF) under one or more 004 * contributor license agreements. See the NOTICE file distributed with 005 * this work for additional information regarding copyright ownership. 006 * The ASF licenses this file to You under the Apache License, Version 2.0 007 * (the "License"); you may not use this file except in compliance with 008 * the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, software 013 * distributed under the License is distributed on an "AS IS" BASIS, 014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 015 * See the License for the specific language governing permissions and 016 * limitations under the License. 017 */ 018 019 020 package org.apache.commons.digester; 021 022 023 import org.apache.commons.beanutils.MethodUtils; 024 025 026 /** 027 * <p>Rule implementation that calls a "set parent" method on the top (child) 028 * object, passing the (top-1) (parent) object as an argument.</p> 029 * 030 * <p>This rule now supports more flexible method matching by default. 031 * It is possible that this may break (some) code 032 * written against release 1.1.1 or earlier. 033 * See {@link #isExactMatch()} for more details.</p> 034 */ 035 036 public class SetTopRule extends Rule { 037 038 039 // ----------------------------------------------------------- Constructors 040 041 042 /** 043 * Construct a "set parent" rule with the specified method name. The 044 * "set parent" method's argument type is assumed to be the class of the 045 * parent object. 046 * 047 * @param digester The associated Digester 048 * @param methodName Method name of the "set parent" method to call 049 * 050 * @deprecated The digester instance is now set in the {@link Digester#addRule} method. 051 * Use {@link #SetTopRule(String methodName)} instead. 052 */ 053 public SetTopRule(Digester digester, String methodName) { 054 055 this(methodName); 056 057 } 058 059 060 /** 061 * Construct a "set parent" rule with the specified method name. 062 * 063 * @param digester The associated Digester 064 * @param methodName Method name of the "set parent" method to call 065 * @param paramType Java class of the "set parent" method's argument 066 * (if you wish to use a primitive type, specify the corresonding 067 * Java wrapper class instead, such as <code>java.lang.Boolean</code> 068 * for a <code>boolean</code> parameter) 069 * 070 * @deprecated The digester instance is now set in the {@link Digester#addRule} method. 071 * Use {@link #SetTopRule(String methodName, String paramType)} instead. 072 */ 073 public SetTopRule(Digester digester, String methodName, 074 String paramType) { 075 076 this(methodName, paramType); 077 078 } 079 080 /** 081 * Construct a "set parent" rule with the specified method name. The 082 * "set parent" method's argument type is assumed to be the class of the 083 * parent object. 084 * 085 * @param methodName Method name of the "set parent" method to call 086 */ 087 public SetTopRule(String methodName) { 088 089 this(methodName, null); 090 091 } 092 093 094 /** 095 * Construct a "set parent" rule with the specified method name. 096 * 097 * @param methodName Method name of the "set parent" method to call 098 * @param paramType Java class of the "set parent" method's argument 099 * (if you wish to use a primitive type, specify the corresonding 100 * Java wrapper class instead, such as <code>java.lang.Boolean</code> 101 * for a <code>boolean</code> parameter) 102 */ 103 public SetTopRule(String methodName, 104 String paramType) { 105 106 this.methodName = methodName; 107 this.paramType = paramType; 108 109 } 110 111 112 // ----------------------------------------------------- Instance Variables 113 114 115 /** 116 * The method name to call on the child object. 117 */ 118 protected String methodName = null; 119 120 121 /** 122 * The Java class name of the parameter type expected by the method. 123 */ 124 protected String paramType = null; 125 126 /** 127 * Should we use exact matching. Default is no. 128 */ 129 protected boolean useExactMatch = false; 130 131 132 // --------------------------------------------------------- Public Methods 133 134 /** 135 * <p>Is exact matching being used.</p> 136 * 137 * <p>This rule uses <code>org.apache.commons.beanutils.MethodUtils</code> 138 * to introspect the relevent objects so that the right method can be called. 139 * Originally, <code>MethodUtils.invokeExactMethod</code> was used. 140 * This matches methods very strictly 141 * and so may not find a matching method when one exists. 142 * This is still the behaviour when exact matching is enabled.</p> 143 * 144 * <p>When exact matching is disabled, <code>MethodUtils.invokeMethod</code> is used. 145 * This method finds more methods but is less precise when there are several methods 146 * with correct signatures. 147 * So, if you want to choose an exact signature you might need to enable this property.</p> 148 * 149 * <p>The default setting is to disable exact matches.</p> 150 * 151 * @return true iff exact matching is enabled 152 * @since Digester Release 1.1.1 153 */ 154 public boolean isExactMatch() { 155 156 return useExactMatch; 157 } 158 159 /** 160 * <p>Set whether exact matching is enabled.</p> 161 * 162 * <p>See {@link #isExactMatch()}.</p> 163 * 164 * @param useExactMatch should this rule use exact method matching 165 * @since Digester Release 1.1.1 166 */ 167 public void setExactMatch(boolean useExactMatch) { 168 169 this.useExactMatch = useExactMatch; 170 } 171 172 /** 173 * Process the end of this element. 174 */ 175 public void end() throws Exception { 176 177 // Identify the objects to be used 178 Object child = digester.peek(0); 179 Object parent = digester.peek(1); 180 181 if (digester.log.isDebugEnabled()) { 182 if (child == null) { 183 digester.log.debug("[SetTopRule]{" + digester.match + 184 "} Call [NULL CHILD]." + 185 methodName + "(" + parent + ")"); 186 } else { 187 digester.log.debug("[SetTopRule]{" + digester.match + 188 "} Call " + child.getClass().getName() + "." + 189 methodName + "(" + parent + ")"); 190 } 191 } 192 193 // Call the specified method 194 Class<?> paramTypes[] = new Class<?>[1]; 195 if (paramType != null) { 196 paramTypes[0] = 197 digester.getClassLoader().loadClass(paramType); 198 } else { 199 paramTypes[0] = parent.getClass(); 200 } 201 202 if (useExactMatch) { 203 204 MethodUtils.invokeExactMethod(child, methodName, 205 new Object[]{ parent }, paramTypes); 206 207 } else { 208 209 MethodUtils.invokeMethod(child, methodName, 210 new Object[]{ parent }, paramTypes); 211 212 } 213 } 214 215 216 /** 217 * Render a printable version of this Rule. 218 */ 219 public String toString() { 220 221 StringBuffer sb = new StringBuffer("SetTopRule["); 222 sb.append("methodName="); 223 sb.append(methodName); 224 sb.append(", paramType="); 225 sb.append(paramType); 226 sb.append("]"); 227 return (sb.toString()); 228 229 } 230 231 232 }