content: /*
   * Copyright 1999-2012 Alibaba Group.
   *  
   * Licensed 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 com.alibaba.cobar.parser.util;
  
  /**
   * (created at 2010-7-21)
   * 
   * @author <a href="mailto:shuo.qius@alibaba-inc.com">QIU Shuo</a>
   */
  public final class Pair<K, V> {
  
      private final K key;
      private final V value;
  
      public Pair(K key, V value) {
          this.key = key;
          this.value = value;
      }
  
      public K getKey() {
          return key;
      }
  
      public V getValue() {
          return value;
      }
  
      @Override
      public String toString() {
          StringBuilder sb = new StringBuilder();
          sb.append("(").append(key).append(", ").append(value).append(")");
          return sb.toString();
      }
  
      private static final int HASH_CONST = 37;
  
      @Override
      public int hashCode() {
          int hash = 17;
          if (key == null) {
              hash += HASH_CONST;
          } else {
              hash = hash << 5 + hash << 1 + hash + key.hashCode();
          }
          if (value == null) {
              hash += HASH_CONST;
          } else {
              hash = hash << 5 + hash << 1 + hash + value.hashCode();
          }
          return hash;
      }
  
      @SuppressWarnings("rawtypes")
      @Override
      public boolean equals(Object obj) {
          if (this == obj)
              return true;
          if (!(obj instanceof Pair))
              return false;
          Pair that = (Pair) obj;
          return isEquals(this.key, that.key) && isEquals(this.value, that.value);
      }
  
      private boolean isEquals(Object o1, Object o2) {
          if (o1 == o2)
              return true;
          if (o1 == null)
              return o2 == null;
          return o1.equals(o2);
      }
  
  }
  