001 // Copyright 2004, 2005 The Apache Software Foundation 002 // 003 // Licensed under the Apache License, Version 2.0 (the "License"); 004 // you may not use this file except in compliance with the License. 005 // You may obtain a copy of the License at 006 // 007 // http://www.apache.org/licenses/LICENSE-2.0 008 // 009 // Unless required by applicable law or agreed to in writing, software 010 // distributed under the License is distributed on an "AS IS" BASIS, 011 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 012 // See the License for the specific language governing permissions and 013 // limitations under the License. 014 015 package org.apache.hivemind.schema.rules; 016 017 import java.lang.reflect.Method; 018 019 import org.apache.hivemind.ApplicationRuntimeException; 020 import org.apache.hivemind.Element; 021 import org.apache.hivemind.schema.SchemaProcessor; 022 023 /** 024 * Rule used to connect a child object to its parent by invoking a method on the parent, passing the 025 * child. The child object is the top object on the stack and the parent object is the next object 026 * down on the stack. Created from the <code><invoke-parent></code> element. Generally, this 027 * is the last rule in a sequence of rules. 028 * 029 * @author Howard Lewis Ship 030 */ 031 public class InvokeParentRule extends BaseRule 032 { 033 private String _methodName; 034 035 private int _depth = 1; 036 037 public InvokeParentRule() 038 { 039 040 } 041 042 public InvokeParentRule(String methodName) 043 { 044 _methodName = methodName; 045 } 046 047 /** 048 * Invokes the named method on the parent object (using reflection). 049 */ 050 public void begin(SchemaProcessor processor, Element element) 051 { 052 Object child = processor.peek(); 053 Class childClass = child == null ? null : child.getClass(); 054 Object parent = processor.peek(_depth); 055 056 try 057 { 058 Method m = findMethod(parent, _methodName, childClass); 059 060 m.invoke(parent, new Object[] 061 { child }); 062 } 063 catch (Exception ex) 064 { 065 throw new ApplicationRuntimeException(RulesMessages.errorInvokingMethod( 066 _methodName, 067 parent, 068 getLocation(), 069 ex), getLocation(), ex); 070 } 071 } 072 073 public String getMethodName() 074 { 075 return _methodName; 076 } 077 078 public void setMethodName(String string) 079 { 080 _methodName = string; 081 } 082 083 /** 084 * @since 1.1 085 */ 086 public int getDepth() 087 { 088 return _depth; 089 } 090 091 /** 092 * Sets the depth of the parent object. The default is 1. 093 */ 094 public void setDepth(int i) 095 { 096 _depth = i; 097 } 098 099 /** 100 * Searches for the *first* public method the has the right name, and takes a single parameter 101 * that is compatible with the parameter type. 102 * 103 * @throws NoSuchMethodException 104 * if a method can't be found 105 */ 106 private Method findMethod(Object target, String name, Class parameterType) 107 throws NoSuchMethodException 108 { 109 Method[] methods = target.getClass().getMethods(); 110 111 for (int i = 0; i < methods.length; i++) 112 { 113 Method m = methods[i]; 114 Class[] parameterTypes = m.getParameterTypes(); 115 116 if (parameterTypes.length != 1) 117 continue; 118 119 if (!m.getName().equals(name)) 120 continue; 121 122 if ((parameterType != null && parameterTypes[0].isAssignableFrom(parameterType)) 123 || (parameterType == null && !parameterTypes[0].isPrimitive())) 124 return m; 125 } 126 127 throw new NoSuchMethodException(name); 128 } 129 }