/*
 * 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.pig.impl.util;

import java.io.Serializable;

/**
 * Copy of C++ STL pair container.
 */
public class Pair<T, U> implements Serializable {

    private static final long serialVersionUID = 1L;
    public T first;
    public U second;

    /**
     * @param f First element in pair.
     * @param s Second element in pair.
     */
    public Pair(T f, U s) {
        first = f;
        second = s;
    }
    
    /* (non-Javadoc)
     * @see java.lang.Object#toString()
     */
    @Override
    public String toString() {
        return "[" + first.toString() +"," + second.toString() + "]";
    }

    @Override
    public int hashCode() {
        return (((this.first == null ? 1 : this.first.hashCode()) * 17)
                + (this.second == null ? 1 : this.second.hashCode()) * 19);
    }
    
    @Override
    public boolean equals(Object other) {
        if(other == null) {
            return false;
        }
        
        if(! (other instanceof Pair)) {
            return false;
        }
        
        Pair otherPair = (Pair) other;
        
        if(this.first == null) {
            if(otherPair.first != null) {
                return false;
            } else {
                return true;
            }
        }
        
        if(this.second == null) {
            if(otherPair.second != null) {
                return false;
            } else {
                return true;
            }
        }
        
        if(this.first.equals(otherPair.first) && this.second.equals(otherPair.second)) {
            return true;
        } else {
            return false;
        }
    }
}
