content: /*
   * 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.activemq.artemis.api.core;
  
  import java.io.Serializable;
  import java.util.Objects;
  
  /**
   * A Pair is a holder for 2 objects.
   * <p>
   * This is a utility class.
   */
  public final class Pair<A, B> implements Serializable {
  
     private static final long serialVersionUID = -2496357457812368127L;
  
     public Pair(final A a, final B b) {
        this.a = a;
  
        this.b = b;
     }
  
     private A a;
  
     private B b;
  
     private int hash = -1;
  
     @Override
     public int hashCode() {
        if (hash == -1) {
           if (a == null && b == null) {
              return super.hashCode();
           } else {
              hash = Objects.hash(a, b);
           }
        }
        return hash;
     }
  
     @Override
     public boolean equals(final Object obj) {
        if (obj == this) {
           return true;
        }
        if (!(obj instanceof Pair<?, ?> other)) {
           return false;
        }
  
        return Objects.equals(other.a, a) &&
               Objects.equals(other.b, b);
     }
  
     @Override
     public String toString() {
        return "Pair[a=" + a + ", b=" + b + "]";
     }
  
     public void setA(A a) {
        hash = -1;
        this.a = a;
     }
  
     public A getA() {
        return a;
     }
  
     public void setB(B b) {
        hash = -1;
        this.b = b;
     }
  
     public B getB() {
        return b;
     }
  }
  