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}