1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 18 package org.apache.commons.jexl3.introspection; 19 20 import org.apache.commons.jexl3.JexlException; 21 22 /** 23 * Interface used for setting values that appear to be properties. 24 * Ex. 25 * <code> 26 * ${foo.bar = "hello"} 27 * </code> 28 * 29 * @since 1.0 30 */ 31 public interface JexlPropertySet { 32 /** 33 * Method used to set the property value of an object. 34 * 35 * @param obj Object on which the property setter will be called with the value 36 * @param arg value to be set 37 * @return the value returned from the set operation (impl specific) 38 * @throws Exception on any error. 39 */ 40 Object invoke(Object obj, Object arg) throws Exception; 41 42 /** 43 * Attempts to reuse this JexlPropertySet, checking that it is compatible with 44 * the actual set of arguments. 45 * 46 * @param obj the object to invoke the get upon 47 * @param key the property key to get 48 * @param value the property value to set 49 * @return the result of the method invocation that should be checked by tryFailed to determine if it succeeded 50 * or failed. 51 * @throws JexlException.TryFailed if the underlying method was invoked but threw an exception 52 * ({@link java.lang.reflect.InvocationTargetException}) 53 */ 54 Object tryInvoke(Object obj, Object key, Object value) throws JexlException.TryFailed; 55 56 /** 57 * Checks whether a tryInvoke failed or not. 58 * 59 * @param rval the value returned by tryInvoke 60 * @return true if tryInvoke failed, false otherwise 61 */ 62 boolean tryFailed(Object rval); 63 64 /** 65 * Specifies if this JexlPropertySet is cacheable and able to be reused for 66 * this class of object it was returned for. 67 * 68 * @return true if can be reused for this class, false if not 69 */ 70 boolean isCacheable(); 71 }