001 /* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 018 package org.apache.commons.jexl2.internal; 019 import java.util.List; 020 import java.lang.reflect.Array; 021 /** 022 * Specialized executor to set a property in a List or array. 023 * @since 2.0 024 */ 025 public final class ListSetExecutor extends AbstractExecutor.Set { 026 /** The java.lang.reflect.Array.get method used as an active marker in ListGet. */ 027 private static final java.lang.reflect.Method ARRAY_SET = 028 initMarker(Array.class, "set", Object.class, Integer.TYPE, Object.class); 029 /** The java.util.obj.set method used as an active marker in ListSet. */ 030 private static final java.lang.reflect.Method LIST_SET = 031 initMarker(List.class, "set", Integer.TYPE, Object.class); 032 /** The property. */ 033 private final Integer property; 034 035 /** 036 * Creates an instance checking for the List interface or Array capability. 037 * @param is the introspector 038 * @param clazz the class that might implement the map interface 039 * @param key the key to use in obj.set(key,value) 040 * @param value the value to use in obj.set(key,value) 041 */ 042 public ListSetExecutor(Introspector is, Class<?> clazz, Integer key, Object value) { 043 super(clazz, discover(clazz)); 044 property = key; 045 } 046 047 /** {@inheritDoc} */ 048 @Override 049 public Object getTargetProperty() { 050 return property; 051 } 052 053 /** {@inheritDoc} */ 054 @Override 055 public Object execute(final Object obj, Object value) { 056 if (method == ARRAY_SET) { 057 java.lang.reflect.Array.set(obj, property.intValue(), value); 058 } else { 059 @SuppressWarnings("unchecked") // LSE should only be created for array or list types 060 final List<Object> list = (List<Object>) obj; 061 list.set(property.intValue(), value); 062 } 063 return value; 064 } 065 066 /** {@inheritDoc} */ 067 @Override 068 public Object tryExecute(final Object obj, Object key, Object value) { 069 if (obj != null && method != null 070 && objectClass.equals(obj.getClass()) 071 && key instanceof Integer) { 072 if (method == ARRAY_SET) { 073 Array.set(obj, ((Integer) key).intValue(), value); 074 } else { 075 @SuppressWarnings("unchecked") // LSE should only be created for array or list types 076 final List<Object> list = (List<Object>) obj; 077 list.set(((Integer) key).intValue(), value); 078 } 079 return value; 080 } 081 return TRY_FAILED; 082 } 083 084 085 /** 086 * Finds the method to perform 'set' on a obj of array. 087 * @param clazz the class to introspect 088 * @return a marker method, obj.set or array.set 089 */ 090 static java.lang.reflect.Method discover(Class<?> clazz) { 091 if (clazz.isArray()) { 092 // we could verify if the call can be performed but it does not change 093 // the fact we would fail... 094 // Class<?> formal = clazz.getComponentType(); 095 // Class<?> actual = value == null? Object.class : value.getClass(); 096 // if (IntrospectionUtils.isMethodInvocationConvertible(formal, actual, false)) { 097 return ARRAY_SET; 098 // } 099 } 100 if (List.class.isAssignableFrom(clazz)) { 101 return LIST_SET; 102 } 103 return null; 104 } 105 }