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 */ 017 018 package org.apache.commons.jexl2.introspection; 019 020 /** 021 * Interface used for setting values that appear to be properties. 022 * Ex. 023 * <code> 024 * ${foo.bar = "hello"} 025 * </code> 026 * @since 1.0 027 * @author <a href="mailto:geirm@optonline.net">Geir Magnusson Jr.</a> 028 * @version $Id: JexlPropertySet.java 889760 2009-12-11 18:42:49Z sebb $ 029 */ 030 public interface JexlPropertySet { 031 /** 032 * Method used to set the property value of an object. 033 * 034 * @param obj Object on which the property setter will be called with the value 035 * @param arg value to be set 036 * @return the value returned from the set operation (impl specific) 037 * @throws Exception on any error. 038 */ 039 Object invoke(Object obj, Object arg) throws Exception; 040 041 /** 042 * Attempts to reuse this JexlPropertySet, checking that it is compatible with 043 * the actual set of arguments. 044 * @param obj the object to invoke the the get upon 045 * @param key the property key to get 046 * @param value the property value to set 047 * @return the result of the method invocation that should be checked by tryFailed to determine if it succeeded 048 * or failed. 049 */ 050 Object tryInvoke(Object obj, Object key, Object value); 051 052 /** 053 * Checks whether a tryInvoke failed or not. 054 * @param rval the value returned by tryInvoke 055 * @return true if tryInvoke failed, false otherwise 056 */ 057 boolean tryFailed(Object rval); 058 059 /** 060 * Specifies if this JexlPropertySet is cacheable and able to be reused for 061 * this class of object it was returned for. 062 * 063 * @return true if can be reused for this class, false if not 064 */ 065 boolean isCacheable(); 066 }