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 * Specifies if this JexlPropertySet is cacheable and able to be reused for
44 * this class of object it was returned for.
45 *
46 * @return true if can be reused for this class, false if not
47 */
48 boolean isCacheable();
49
50 /**
51 * Checks whether a tryInvoke failed or not.
52 *
53 * @param rval the value returned by tryInvoke
54 * @return true if tryInvoke failed, false otherwise
55 */
56 boolean tryFailed(Object rval);
57
58 /**
59 * Attempts to reuse this JexlPropertySet, checking that it is compatible with
60 * the actual set of arguments.
61 *
62 * @param obj the object to invoke the get upon
63 * @param key the property key to get
64 * @param value the property value to set
65 * @return the result of the method invocation that should be checked by tryFailed to determine if it succeeded
66 * or failed.
67 * @throws JexlException.TryFailed if the underlying method was invoked but threw an exception
68 * ({@link java.lang.reflect.InvocationTargetException})
69 */
70 Object tryInvoke(Object obj, Object key, Object value) throws JexlException.TryFailed;
71 }