    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.lang.reflect.InvocationTargetException;
    020import org.apache.commons.jexl3.JexlException;
    021
    022/**
    023 * Specialized executor to set a property of an object.
    024 * <p>Duck as in duck-typing for an interface like:
    025 * <code>
    026 * interface Setable {
    027 *      Object set(Object property, Object value);
    028 * }
    029 * </code>
    030 * or
    031 * <code>
    032 * interface Putable {
    033 *      Object put(Object property, Object value);
    034 * }
    035 * </code>
    036 * </p>
    037 * @since 2.0
    038 */
    039public final class DuckSetExecutor extends AbstractExecutor.Set {
    040    /** The property, may be null. */
    041    private final Object property;
    042    /** The property value class. */
    043    private final Class<?> valueClass;
    044
    045    /**
    046     * Discovers a DuckSetExecutor.
    047     *
    048     * @param is the introspector
    049     * @param clazz the class to find the set method from
    050     * @param key the key to use as 1st argument to the set method
    051     * @param value the value to use as 2nd argument to the set method
    052     * @return the executor if found, null otherwise
    053     */
    054    public static DuckSetExecutor discover(final Introspector is, final Class<?> clazz, final Object key, final Object value) {
    055        java.lang.reflect.Method method = is.getMethod(clazz, "set", makeArgs(key, value));
    056        if (method == null) {
    057            method = is.getMethod(clazz, "put", makeArgs(key, value));
    058        }
    059        return method == null? null : new DuckSetExecutor(clazz, method, key, value);
    060    }
    061
    062    /**
    063     * Creates an instance.
    064     * @param clazz the class the set method applies to
    065     * @param method the method called through this executor
    066     * @param key the key to use as 1st argument to the set method
    067     * @param value the value to use as 2nd argument to the set method
    068     */
    069    private DuckSetExecutor(final Class<?> clazz, final java.lang.reflect.Method method, final Object key, final Object value) {
    070        super(clazz, method);
    071        property = key;
    072        valueClass = classOf(value);
    073    }
    074
    075    @Override
    076    public Object getTargetProperty() {
    077        return property;
    078    }
    079
    080    @Override
    081    public Object invoke(final Object obj, final Object value) throws IllegalAccessException, InvocationTargetException {
    082        final Object[] pargs = {property, value};
    083        if (method != null) {
    084                method.invoke(obj, pargs);
    085            }
    086        return value;
    087    }
    088
    089    @Override
    090    public Object tryInvoke(final Object obj, final Object key, final Object value) {
    091        if (obj != null
    092            && objectClass.equals(obj.getClass())
    093            && method !=  null
    094            && ((property != null && property.equals(key))
    095                || (property == null && key == null))
    096            && valueClass.equals(classOf(value))) {
    097            try {
    098                final Object[] args = {property, value};
    099                method.invoke(obj, args);
    100                return value;
    101            } catch (IllegalAccessException | IllegalArgumentException xill) {
    102                return TRY_FAILED;// fail
    103            } catch (final InvocationTargetException xinvoke) {
    104                throw JexlException.tryFailed(xinvoke); // throw
    105            }
    106        }
    107        return TRY_FAILED;
    108    }
    109}