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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *   http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing,
13   * software distributed under the License is distributed on an
14   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   * KIND, either express or implied.  See the License for the
16   * specific language governing permissions and limitations
17   * under the License.
18   */
19  package org.apache.maven.toolchain.model;
20  
21  import java.io.Serializable;
22  
23  public abstract class BaseObject implements Serializable, Cloneable {
24      protected transient ChildrenTracking childrenTracking;
25  
26      protected Object delegate;
27  
28      public BaseObject() {}
29  
30      public BaseObject(Object delegate, BaseObject parent) {
31          this.delegate = delegate;
32          this.childrenTracking = parent != null ? parent::replace : null;
33      }
34  
35      public BaseObject(Object delegate, ChildrenTracking parent) {
36          this.delegate = delegate;
37          this.childrenTracking = parent;
38      }
39  
40      public Object getDelegate() {
41          return delegate;
42      }
43  
44      public void update(Object newDelegate) {
45          if (delegate != newDelegate) {
46              if (childrenTracking != null) {
47                  childrenTracking.replace(delegate, newDelegate);
48              }
49              delegate = newDelegate;
50          }
51      }
52  
53      protected boolean replace(Object oldDelegate, Object newDelegate) {
54          return false;
55      }
56  
57      @FunctionalInterface
58      protected interface ChildrenTracking {
59          boolean replace(Object oldDelegate, Object newDelegate);
60      }
61  }