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 package org.apache.commons.jexl2.internal;
018
019 import java.lang.reflect.InvocationTargetException;
020
021 /**
022 * Specialized executor to set a property of an object.
023 * <p>Duck as in duck-typing for an interface like:
024 * <code>
025 * interface Set {
026 * Object set(Object property, Object value);
027 * }
028 * </code>
029 * </p>
030 * @since 2.0
031 */
032 public final class DuckSetExecutor extends AbstractExecutor.Set {
033 /** The property. */
034 private final Object property;
035
036 /**
037 * Creates an instance.
038 *@param is the introspector
039 *@param clazz the class to find the set method from
040 *@param key the key to use as 1st argument to the set method
041 *@param value the value to use as 2nd argument to the set method
042 */
043 public DuckSetExecutor(Introspector is, Class<?> clazz, Object key, Object value) {
044 super(clazz, discover(is, clazz, key, value));
045 property = key;
046 }
047
048 /** {@inheritDoc} */
049 @Override
050 public Object getTargetProperty() {
051 return property;
052 }
053
054 /** {@inheritDoc} */
055 @Override
056 public Object execute(Object obj, Object value)
057 throws IllegalAccessException, InvocationTargetException {
058 Object[] pargs = {property, value};
059 if (method != null) {
060 method.invoke(obj, pargs);
061 }
062 return value;
063 }
064
065 /** {@inheritDoc} */
066 @Override
067 public Object tryExecute(Object obj, Object key, Object value) {
068 if (obj != null && method != null
069 // ensure method name matches the property name
070 && property.equals(key)
071 && objectClass.equals(obj.getClass())) {
072 try {
073 Object[] args = {property, value};
074 method.invoke(obj, args);
075 return value;
076 } catch (InvocationTargetException xinvoke) {
077 return TRY_FAILED; // fail
078 } catch (IllegalAccessException xill) {
079 return TRY_FAILED;// fail
080 }
081 }
082 return TRY_FAILED;
083 }
084
085 /**
086 * Discovers the method for a {@link DuckSet}.
087 *@param is the introspector
088 *@param clazz the class to find the set method from
089 *@param key the key to use as 1st argument to the set method
090 *@param value the value to use as 2nd argument to the set method
091 *@return the method if found, null otherwise
092 */
093 private static java.lang.reflect.Method discover(Introspector is,
094 Class<?> clazz, Object key, Object value) {
095 return is.getMethod(clazz, "set", makeArgs(key, value));
096 }
097 }