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 get a property from a List or array. 023 * @since 2.0 024 */ 025 public final class ListGetExecutor extends AbstractExecutor.Get { 026 /** The java.lang.reflect.Array.get method used as an active marker in ListGet. */ 027 private static final java.lang.reflect.Method ARRAY_GET = 028 initMarker(Array.class, "get", Object.class, Integer.TYPE); 029 /** The java.util.obj.get method used as an active marker in ListGet. */ 030 private static final java.lang.reflect.Method LIST_GET = 031 initMarker(List.class, "get", Integer.TYPE); 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 to introspect 039 * @param key the key to use in obj.get(key) 040 */ 041 public ListGetExecutor(Introspector is, Class<?> clazz, Integer key) { 042 super(clazz, discover(clazz)); 043 property = key; 044 } 045 046 /** {@inheritDoc} */ 047 @Override 048 public Object getTargetProperty() { 049 return property; 050 } 051 052 /** 053 * Get the property from the obj or array. 054 * @param obj the List/array. 055 * @return obj.get(key) 056 */ 057 @Override 058 public Object execute(final Object obj) { 059 if (method == ARRAY_GET) { 060 return java.lang.reflect.Array.get(obj, property.intValue()); 061 } else { 062 return ((List<?>) obj).get(property.intValue()); 063 } 064 } 065 066 /** {@inheritDoc} */ 067 @Override 068 public Object tryExecute(final Object obj, Object key) { 069 if (obj != null && method != null 070 && objectClass.equals(obj.getClass()) 071 && key instanceof Integer) { 072 if (method == ARRAY_GET) { 073 return java.lang.reflect.Array.get(obj, ((Integer) key).intValue()); 074 } else { 075 return ((List<?>) obj).get(((Integer) key).intValue()); 076 } 077 } 078 return TRY_FAILED; 079 } 080 081 082 /** 083 * Finds the method to perform the get on a obj of array. 084 * @param clazz the class to introspect 085 * @return a marker method, obj.get or array.get 086 */ 087 static java.lang.reflect.Method discover(Class<?> clazz) { 088 //return discoverList(false, clazz, property); 089 if (clazz.isArray()) { 090 return ARRAY_GET; 091 } 092 if (List.class.isAssignableFrom(clazz)) { 093 return LIST_GET; 094 } 095 return null; 096 } 097 }