/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you under the Apache License, Version 2.0 (the
    * "License"); you may not use this file except in compliance
    * with the License.  You may obtain a copy of the License at
    *
   *   http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing,
   * software distributed under the License is distributed on an
   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   * KIND, either express or implied.  See the License for the
   * specific language governing permissions and limitations
   * under the License.
   */
  package org.apache.maven.artifact.repository.metadata;
  
  import java.io.Serializable;
  
  import static java.util.Objects.requireNonNull;
  
  public abstract class BaseObject implements Serializable, Cloneable {
      protected transient ChildrenTracking childrenTracking;
  
      protected Object delegate;
  
      public BaseObject() {}
  
      public BaseObject(Object delegate, BaseObject parent) {
          this.delegate = requireNonNull(delegate, "delegate cannot be null");
          this.childrenTracking = parent != null ? parent::replace : null;
      }
  
      public BaseObject(Object delegate, ChildrenTracking parent) {
          this.delegate = requireNonNull(delegate, "delegate cannot be null");
          this.childrenTracking = parent;
      }
  
      public Object getDelegate() {
          return delegate;
      }
  
      public void update(Object newDelegate) {
          if (delegate != newDelegate) {
              if (childrenTracking != null) {
                  childrenTracking.replace(delegate, newDelegate);
              }
              delegate = newDelegate;
          }
      }
  
      protected boolean replace(Object oldDelegate, Object newDelegate) {
          return false;
      }
  
      @FunctionalInterface
      protected interface ChildrenTracking {
          boolean replace(Object oldDelegate, Object newDelegate);
      }
  }