001/* 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with 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, 013 * software distributed under the License is distributed on an 014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 015 * KIND, either express or implied. See the License for the 016 * specific language governing permissions and limitations 017 * under the License. 018 * 019 */ 020package org.apache.mina.statemachine.transition; 021 022import java.lang.reflect.InvocationTargetException; 023import java.lang.reflect.Method; 024import java.util.Arrays; 025 026import org.apache.mina.statemachine.State; 027import org.apache.mina.statemachine.StateMachine; 028import org.apache.mina.statemachine.context.StateContext; 029import org.slf4j.Logger; 030import org.slf4j.LoggerFactory; 031 032/** 033 * {@link SelfTransition} which invokes a {@link Method}. The {@link Method} can 034 * have zero or any number of StateContext and State regarding order 035 * <p> 036 * Normally you wouldn't create instances of this class directly but rather use 037 * the {@link SelfTransition} annotation to define the methods which should be 038 * used as transitions in your state machine and then let 039 * {@link org.apache.mina.statemachine.StateMachineFactory} create a 040 * {@link StateMachine} for you. 041 * </p> 042 * 043 * @author <a href="http://mina.apache.org">Apache MINA Project</a> 044 */ 045public class MethodSelfTransition extends AbstractSelfTransition { 046 private static final Logger LOGGER = LoggerFactory.getLogger(MethodTransition.class); 047 048 private Method method; 049 050 private final Object target; 051 052 private static final Object[] EMPTY_ARGUMENTS = new Object[0]; 053 054 public MethodSelfTransition(Method method, Object target) { 055 super(); 056 this.method = method; 057 this.target = target; 058 } 059 060 /** 061 * Creates a new instance 062 * 063 * @param methodName 064 * the target method. 065 * @param target 066 * the target object. 067 */ 068 public MethodSelfTransition(String methodName, Object target) { 069 070 this.target = target; 071 072 Method[] candidates = target.getClass().getMethods(); 073 Method result = null; 074 075 for (int i = 0; i < candidates.length; i++) { 076 if (candidates[i].getName().equals(methodName)) { 077 if (result != null) { 078 throw new AmbiguousMethodException(methodName); 079 } 080 result = candidates[i]; 081 } 082 } 083 084 if (result == null) { 085 throw new NoSuchMethodException(methodName); 086 } 087 088 this.method = result; 089 090 } 091 092 /** 093 * @return the target {@link Method}. 094 */ 095 public Method getMethod() { 096 return method; 097 } 098 099 public boolean doExecute(StateContext stateContext, State state) { 100 Class<?>[] types = method.getParameterTypes(); 101 102 if (types.length == 0) { 103 invokeMethod(EMPTY_ARGUMENTS); 104 return true; 105 } 106 107 if (types.length > 2) { 108 return false; 109 } 110 111 Object[] args = new Object[types.length]; 112 113 int i = 0; 114 115 if (types[i].isAssignableFrom(StateContext.class)) { 116 args[i++] = stateContext; 117 } 118 if ((i < types.length) && types[i].isAssignableFrom(State.class)) { 119 args[i++] = state; 120 } 121 122 invokeMethod(args); 123 124 return true; 125 } 126 127 private void invokeMethod(Object[] arguments) { 128 try { 129 if (LOGGER.isDebugEnabled()) { 130 LOGGER.debug("Executing method " + method + " with arguments " + Arrays.asList(arguments)); 131 } 132 method.invoke(target, arguments); 133 } catch (InvocationTargetException ite) { 134 if (ite.getCause() instanceof RuntimeException) { 135 throw (RuntimeException) ite.getCause(); 136 } 137 throw new MethodInvocationException(method, ite); 138 } catch (IllegalAccessException iae) { 139 throw new MethodInvocationException(method, iae); 140 } 141 } 142 143}