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 * https://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 package org.apache.commons.configuration2.builder;
18
19 import org.apache.commons.configuration2.beanutils.BeanHelper;
20 import org.apache.commons.configuration2.ex.ConfigurationRuntimeException;
21
22 /**
23 * <p>
24 * A specialized implementation of {@code DefaultParametersHandler} that copies the properties of a
25 * {@link BuilderParameters} object (passed at construction time) onto the object to be initialized.
26 * </p>
27 * <p>
28 * Using this handler implementation makes specifying default values pretty straight-forward: Just create a
29 * corresponding parameters object, initialize it as desired, and pass it to this class. When invoked the handler uses
30 * functionality from <em>Commons BeanUtils</em> to copy all properties defined in the associated parameters object onto
31 * the target object. This is based on reflection. Properties not available for the target object are silently ignored.
32 * If an exception occurs during the copy operation, it is re-thrown as a runtime exception.
33 * </p>
34 * <p>
35 * Note that there is no default way to create a defensive copy of the passed in parameters object; therefore, the
36 * reference is stored. This makes it possible to change the parameters object later on, and the changes will be
37 * effective when initializing objects afterwards. Client code should not rely on this feature.
38 * </p>
39 *
40 * @since 2.0
41 */
42 public class CopyObjectDefaultHandler implements DefaultParametersHandler<Object> {
43
44 /** The source object with the properties to be initialized. */
45 private final BuilderParameters source;
46
47 /**
48 * Creates a new instance of {@code CopyObjectDefaultHandler} and initializes it with the specified source object. The
49 * properties defined by the source object are copied onto the objects to be initialized.
50 *
51 * @param src the source object (must not be <strong>null</strong>)
52 * @throws IllegalArgumentException if the source object is <strong>null</strong>
53 */
54 public CopyObjectDefaultHandler(final BuilderParameters src) {
55 if (src == null) {
56 throw new IllegalArgumentException("Source object must not be null.");
57 }
58 source = src;
59 }
60
61 /**
62 * Gets the source object of this handler. This is the object whose properties are copied on the objects to be
63 * initialized.
64 *
65 * @return the source object of this {@code CopyObjectDefaultHandler}
66 */
67 public BuilderParameters getSource() {
68 return source;
69 }
70
71 /**
72 * {@inheritDoc} This implementation uses {@code PropertyUtils.copyProperties()} to copy all defined properties from the
73 * source object onto the passed in parameters object. Both the map with properties (obtained via the
74 * {@code getParameters()} method of the source parameters object) and other properties of the source object are copied.
75 *
76 * @throws ConfigurationRuntimeException if an exception occurs
77 * @see BuilderParameters#getParameters()
78 */
79 @Override
80 public void initializeDefaults(final Object parameters) {
81 try {
82 BeanHelper.copyProperties(parameters, getSource().getParameters());
83 BeanHelper.copyProperties(parameters, getSource());
84 } catch (final Exception e) {
85 // Handle all reflection-related exceptions the same way
86 throw new ConfigurationRuntimeException(e);
87 }
88 }
89 }