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.jexl2.internal;
018
019import 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 */
032public 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}