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 */ 017package org.apache.commons.jexl3.internal.introspection; 018 019import java.util.List; 020import java.lang.reflect.Array; 021 022/** 023 * Specialized executor to set a property in a List or array. 024 * @since 2.0 025 */ 026public final class ListSetExecutor extends AbstractExecutor.Set { 027 /** The java.lang.reflect.Array.get method used as an active marker in ListGet. */ 028 private static final java.lang.reflect.Method ARRAY_SET = 029 initMarker(Array.class, "set", Object.class, Integer.TYPE, Object.class); 030 /** The java.util.obj.set method used as an active marker in ListSet. */ 031 private static final java.lang.reflect.Method LIST_SET = 032 initMarker(List.class, "set", Integer.TYPE, Object.class); 033 /** The property. */ 034 private final Integer property; 035 036 /** 037 * Attempts to discover a ListSetExecutor. 038 * 039 * @param is the introspector 040 * @param clazz the class to find the get method from 041 * @param identifier the key to use as an argument to the get method 042 * @param value the value to use as argument in list.put(key,value) 043 * @return the executor if found, null otherwise 044 */ 045 public static ListSetExecutor discover(final Introspector is, 046 final Class<?> clazz, 047 final Object identifier, 048 final Object value) { 049 final Integer index = castInteger(identifier); 050 if (index != null) { 051 if (clazz.isArray()) { 052 // we could verify if the call can be performed but it does not change 053 // the fact we would fail... 054 // Class<?> formal = clazz.getComponentType(); 055 // Class<?> actual = value == null? Object.class : value.getClass(); 056 // if (IntrospectionUtils.isMethodInvocationConvertible(formal, actual, false)) { 057 return new ListSetExecutor(clazz, ARRAY_SET, index); 058 // } 059 } 060 if (List.class.isAssignableFrom(clazz)) { 061 return new ListSetExecutor(clazz, LIST_SET, index); 062 } 063 } 064 return null; 065 } 066 067 /** 068 * Creates an instance. 069 * 070 * @param clazz the class the set method applies to 071 * @param method the method called through this executor 072 * @param key the key to use as 1st argument to the set method 073 */ 074 private ListSetExecutor(final Class<?> clazz, final java.lang.reflect.Method method, final Integer key) { 075 super(clazz, method); 076 property = key; 077 } 078 079 @Override 080 public Object getTargetProperty() { 081 return property; 082 } 083 084 @Override 085 public Object invoke(final Object obj, final Object value) { 086 if (method == ARRAY_SET) { 087 Array.set(obj, property, value); 088 } else { 089 @SuppressWarnings("unchecked") // LSE should only be created for array or list types 090 final List<Object> list = (List<Object>) obj; 091 list.set(property, value); 092 } 093 return value; 094 } 095 096 @Override 097 public Object tryInvoke(final Object obj, final Object key, final Object value) { 098 final Integer index = castInteger(key); 099 if (obj != null && method != null 100 && objectClass.equals(obj.getClass()) 101 && index != null) { 102 if (method == ARRAY_SET) { 103 Array.set(obj, index, value); 104 } else { 105 @SuppressWarnings("unchecked") // LSE should only be created for array or list types 106 final List<Object> list = (List<Object>) obj; 107 list.set(index, value); 108 } 109 return value; 110 } 111 return TRY_FAILED; 112 } 113}