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 * Attempts to reuse this JexlPropertySet, checking that it is compatible with 044 * the actual set of arguments. 045 * 046 * @param obj the object to invoke the get upon 047 * @param key the property key to get 048 * @param value the property value to set 049 * @return the result of the method invocation that should be checked by tryFailed to determine if it succeeded 050 * or failed. 051 * @throws JexlException.TryFailed if the underlying method was invoked but threw an exception 052 * ({@link java.lang.reflect.InvocationTargetException}) 053 */ 054 Object tryInvoke(Object obj, Object key, Object value) throws JexlException.TryFailed; 055 056 /** 057 * Checks whether a tryInvoke failed or not. 058 * 059 * @param rval the value returned by tryInvoke 060 * @return true if tryInvoke failed, false otherwise 061 */ 062 boolean tryFailed(Object rval); 063 064 /** 065 * Specifies if this JexlPropertySet is cacheable and able to be reused for 066 * this class of object it was returned for. 067 * 068 * @return true if can be reused for this class, false if not 069 */ 070 boolean isCacheable(); 071}