1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 18 package org.apache.commons.proxy.invoker; 19 20 import org.apache.commons.proxy.Invoker; 21 22 import java.lang.reflect.Method; 23 import java.util.HashMap; 24 import java.util.Map; 25 26 /** 27 * An {@link Invoker} implementation which merely returns null for all method invocations. This class is 28 * useful for scenarios where the "null object" design pattern is needed. 29 * 30 * @author James Carman 31 * @since 1.0 32 */ 33 public class NullInvoker implements Invoker 34 { 35 private static Map primitiveValueMap = new HashMap(); 36 static 37 { 38 primitiveValueMap.put( Integer.TYPE, new Integer( 0 ) ); 39 primitiveValueMap.put( Long.TYPE, new Long( 0 ) ); 40 primitiveValueMap.put( Short.TYPE, new Short( ( short )0 ) ); 41 primitiveValueMap.put( Byte.TYPE, new Byte( ( byte )0 ) ); 42 primitiveValueMap.put( Float.TYPE, new Float( 0.0f ) ); 43 primitiveValueMap.put( Double.TYPE, new Double( 0.0 ) ); 44 primitiveValueMap.put( Character.TYPE, new Character( ( char )0 ) ); 45 primitiveValueMap.put( Boolean.TYPE, Boolean.FALSE ); 46 } 47 //---------------------------------------------------------------------------------------------------------------------- 48 // InvocationHandler Implementation 49 //---------------------------------------------------------------------------------------------------------------------- 50 51 public Object invoke( Object proxy, Method method, Object[] args ) throws Throwable 52 { 53 final Class returnType = method.getReturnType(); 54 if( returnType.isPrimitive() ) 55 { 56 return primitiveValueMap.get( returnType ); 57 } 58 else 59 { 60 return null; 61 } 62 } 63 } 64