001 /* $Id: SetRootRule.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 method on the root object on the stack, 028 * passing the top object (child) as an argument. 029 * It is important to remember that this rule acts on <code>end</code>.</p> 030 * 031 * <p>This rule now supports more flexible method matching by default. 032 * It is possible that this may break (some) code 033 * written against release 1.1.1 or earlier. 034 * See {@link #isExactMatch()} for more details.</p> 035 */ 036 037 public class SetRootRule extends Rule { 038 039 040 // ----------------------------------------------------------- Constructors 041 042 043 /** 044 * Construct a "set root" rule with the specified method name. The 045 * method's argument type is assumed to be the class of the 046 * child object. 047 * 048 * @param digester The associated Digester 049 * @param methodName Method name of the parent method to call 050 * 051 * @deprecated The digester instance is now set in the {@link Digester#addRule} method. 052 * Use {@link #SetRootRule(String methodName)} instead. 053 */ 054 public SetRootRule(Digester digester, String methodName) { 055 056 this(methodName); 057 058 } 059 060 061 /** 062 * Construct a "set root" rule with the specified method name. 063 * 064 * @param digester The associated Digester 065 * @param methodName Method name of the parent method to call 066 * @param paramType Java class of the parent method's argument 067 * (if you wish to use a primitive type, specify the corresonding 068 * Java wrapper class instead, such as <code>java.lang.Boolean</code> 069 * for a <code>boolean</code> parameter) 070 * 071 * @deprecated The digester instance is now set in the {@link Digester#addRule} method. 072 * Use {@link #SetRootRule(String methodName,String paramType)} instead. 073 */ 074 public SetRootRule(Digester digester, String methodName, 075 String paramType) { 076 077 this(methodName, paramType); 078 079 } 080 081 /** 082 * Construct a "set root" rule with the specified method name. The 083 * method's argument type is assumed to be the class of the 084 * child object. 085 * 086 * @param methodName Method name of the parent method to call 087 */ 088 public SetRootRule(String methodName) { 089 090 this(methodName, null); 091 092 } 093 094 095 /** 096 * Construct a "set root" rule with the specified method name. 097 * 098 * @param methodName Method name of the parent method to call 099 * @param paramType Java class of the parent method's argument 100 * (if you wish to use a primitive type, specify the corresonding 101 * Java wrapper class instead, such as <code>java.lang.Boolean</code> 102 * for a <code>boolean</code> parameter) 103 */ 104 public SetRootRule(String methodName, 105 String paramType) { 106 107 this.methodName = methodName; 108 this.paramType = paramType; 109 110 } 111 112 // ----------------------------------------------------- Instance Variables 113 114 115 /** 116 * The method name to call on the parent 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 /** 136 * <p>Is exact matching being used.</p> 137 * 138 * <p>This rule uses <code>org.apache.commons.beanutils.MethodUtils</code> 139 * to introspect the relevent objects so that the right method can be called. 140 * Originally, <code>MethodUtils.invokeExactMethod</code> was used. 141 * This matches methods very strictly 142 * and so may not find a matching method when one exists. 143 * This is still the behaviour when exact matching is enabled.</p> 144 * 145 * <p>When exact matching is disabled, <code>MethodUtils.invokeMethod</code> is used. 146 * This method finds more methods but is less precise when there are several methods 147 * with correct signatures. 148 * So, if you want to choose an exact signature you might need to enable this property.</p> 149 * 150 * <p>The default setting is to disable exact matches.</p> 151 * 152 * @return true iff exact matching is enabled 153 * @since Digester Release 1.1.1 154 */ 155 public boolean isExactMatch() { 156 157 return useExactMatch; 158 } 159 160 161 /** 162 * <p>Set whether exact matching is enabled.</p> 163 * 164 * <p>See {@link #isExactMatch()}.</p> 165 * 166 * @param useExactMatch should this rule use exact method matching 167 * @since Digester Release 1.1.1 168 */ 169 public void setExactMatch(boolean useExactMatch) { 170 171 this.useExactMatch = useExactMatch; 172 } 173 174 /** 175 * Process the end of this element. 176 */ 177 public void end() throws Exception { 178 179 // Identify the objects to be used 180 Object child = digester.peek(0); 181 Object parent = digester.root; 182 if (digester.log.isDebugEnabled()) { 183 if (parent == null) { 184 digester.log.debug("[SetRootRule]{" + digester.match + 185 "} Call [NULL ROOT]." + 186 methodName + "(" + child + ")"); 187 } else { 188 digester.log.debug("[SetRootRule]{" + digester.match + 189 "} Call " + parent.getClass().getName() + "." + 190 methodName + "(" + child + ")"); 191 } 192 } 193 194 // Call the specified method 195 Class<?> paramTypes[] = new Class<?>[1]; 196 if (paramType != null) { 197 paramTypes[0] = 198 digester.getClassLoader().loadClass(paramType); 199 } else { 200 paramTypes[0] = child.getClass(); 201 } 202 203 if (useExactMatch) { 204 205 MethodUtils.invokeExactMethod(parent, methodName, 206 new Object[]{ child }, paramTypes); 207 208 } else { 209 210 MethodUtils.invokeMethod(parent, methodName, 211 new Object[]{ child }, paramTypes); 212 213 } 214 } 215 216 217 /** 218 * Render a printable version of this Rule. 219 */ 220 public String toString() { 221 222 StringBuffer sb = new StringBuffer("SetRootRule["); 223 sb.append("methodName="); 224 sb.append(methodName); 225 sb.append(", paramType="); 226 sb.append(paramType); 227 sb.append("]"); 228 return (sb.toString()); 229 230 } 231 232 233 }