fe/src/main/java/org/apache/impala/common/Pair.java

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// 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
//
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package org.apache.impala.common;

/**
 * The equivalent of C++'s std::pair<>.
 */
public class Pair<F, S> {
  public F first;
  public S second;

  public Pair(F first, S second) {
    this.first = first;
    this.second = second;
  }

  @Override
  /**
   * A pair is equal if both parts are equal().
   */
  public boolean equals(Object o) {
    if (o instanceof Pair) {
      Pair<F,S> other = (Pair<F,S>) o;
      return this.first.equals(other.first) && this.second.equals(other.second);
    }
    return false;
  }

  @Override
  public int hashCode() {
    int hashFirst = first != null ? first.hashCode() : 0;
    int hashSecond = second != null ? second.hashCode() : 0;

    return (hashFirst + hashSecond) * hashSecond + hashFirst;
  }

  static public <F, S> Pair<F, S> create(F first, S second) {
    return new Pair<F, S>(first, second);
  }

  @Override
  public String toString() {
    return String.format("<%s, %s>", first, second);
  }
}