    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
    018package org.apache.commons.jexl3.introspection;
    019
    020import org.apache.commons.jexl3.JexlException;
    021
    022/**
    023 * Interface used for setting values that appear to be properties.
    024 * Ex.
    025 * <code>
    026 * ${foo.bar = "hello"}
    027 * </code>
    028 *
    029 * @since 1.0
    030 */
    031public interface JexlPropertySet {
    032    /**
    033     * Method used to set the property value of an object.
    034     *
    035     * @param obj Object on which the property setter will be called with the value
    036     * @param arg value to be set
    037     * @return the value returned from the set operation (impl specific)
    038     * @throws Exception on any error.
    039     */
    040    Object invoke(Object obj, Object arg) throws Exception;
    041
    042    /**
    043     * Specifies if this JexlPropertySet is cacheable and able to be reused for
    044     * this class of object it was returned for.
    045     *
    046     * @return true if can be reused for this class, false if not
    047     */
    048    boolean isCacheable();
    049
    050    /**
    051     * Checks whether a tryInvoke failed or not.
    052     *
    053     * @param rval the value returned by tryInvoke
    054     * @return true if tryInvoke failed, false otherwise
    055     */
    056    boolean tryFailed(Object rval);
    057
    058    /**
    059     * Attempts to reuse this JexlPropertySet, checking that it is compatible with
    060     * the actual set of arguments.
    061     *
    062     * @param obj the object to invoke the get upon
    063     * @param key the property key to get
    064     * @param value the property value to set
    065     * @return the result of the method invocation that should be checked by tryFailed to determine if it succeeded
    066     * or failed.
    067     * @throws JexlException.TryFailed if the underlying method was invoked but threw an exception
    068     * ({@link java.lang.reflect.InvocationTargetException})
    069     */
    070    Object tryInvoke(Object obj, Object key, Object value) throws JexlException.TryFailed;
    071}