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   /*
    * Copyright 2012 The Netty Project
    *
    * The Netty Project 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:
    *
    *   https://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 io.netty.util;
  
  import java.util.concurrent.atomic.AtomicLong;
  
  /**
   * Base implementation of {@link Constant}.
   */
  public abstract class AbstractConstant<T extends AbstractConstant<T>> implements Constant<T> {
  
      private static final AtomicLong uniqueIdGenerator = new AtomicLong();
      private final int id;
      private final String name;
      private final long uniquifier;
  
      /**
       * Creates a new instance.
       */
      protected AbstractConstant(int id, String name) {
          this.id = id;
          this.name = name;
          this.uniquifier = uniqueIdGenerator.getAndIncrement();
      }
  
      @Override
      public final String name() {
          return name;
      }
  
      @Override
      public final int id() {
          return id;
      }
  
      @Override
      public final String toString() {
          return name();
      }
  
      @Override
      public final int hashCode() {
          return super.hashCode();
      }
  
      @Override
      public final boolean equals(Object obj) {
          return super.equals(obj);
      }
  
      @Override
      public final int compareTo(T o) {
          if (this == o) {
              return 0;
          }
  
          @SuppressWarnings("UnnecessaryLocalVariable")
          AbstractConstant<T> other = o;
          int returnCode;
  
          returnCode = hashCode() - other.hashCode();
          if (returnCode != 0) {
              return returnCode;
          }
  
          if (uniquifier < other.uniquifier) {
              return -1;
          }
          if (uniquifier > other.uniquifier) {
              return 1;
          }
  
          throw new Error("failed to compare two different constants");
      }
  
  }