com.github.steveash.guavate.ObjIntPair.java Source code

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Here is the source code for com.github.steveash.guavate.ObjIntPair.java

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/**
 * Copyright (C) 2015 - present by OpenGamma Inc. and the OpenGamma group of companies
 *
 * Please see distribution for license.
 */
package com.github.steveash.guavate;

import java.io.Serializable;

import org.apache.commons.lang3.tuple.Pair;

import com.google.common.base.Preconditions;
import com.google.common.collect.ComparisonChain;
import com.google.common.collect.ImmutableList;

/**
 * An immutable pair consisting of an {@code Object} and an {@code int}.
 * <p>
 * This class is similar to {@link Pair} but includes a primitive element.
 * <p>
 * This class is immutable and thread-safe.
 *
 * @param <A> the type of the object
 */
public final class ObjIntPair<A> implements Comparable<ObjIntPair<A>>, Serializable {

    /**
     * The first element in this pair.
     */
    private final A first;

    /**
     * The second element in this pair.
     */
    private final int second;

    //-------------------------------------------------------------------------
    /**
     * Obtains an instance from an {@code Object} and an {@code int}.
     *
     * @param <A> the first element type
     * @param first  the first element
     * @param second  the second element
     * @return a pair formed from the two parameters
     */
    public static <A> ObjIntPair<A> of(A first, int second) {
        return new ObjIntPair<>(first, second);
    }

    /**
     * Obtains an instance from a {@code Pair}.
     *
     * @param <A> the first element type
     * @param pair  the pair to convert
     * @return a pair formed by extracting values from the pair
     */
    public static <A> ObjIntPair<A> ofPair(Pair<A, Integer> pair) {
        Preconditions.checkNotNull(pair, "pair");
        return new ObjIntPair<A>(pair.getLeft(), pair.getRight());
    }

    /**
     * Gets the elements from this pair as a list.
     * <p>
     * The list returns each element in the pair in order.
     *
     * @return the elements as an immutable list
     */
    public ImmutableList<Object> elements() {
        return ImmutableList.of(first, second);
    }

    //-------------------------------------------------------------------------
    /**
     * Converts this pair to an object-based {@code Pair}.
     *
     * @return the object-based pair
     */
    public Pair<A, Integer> toPair() {
        return Pair.of(first, second);
    }

    //-------------------------------------------------------------------------
    /**
     * Compares the pair based on the first element followed by the second element.
     * <p>
     * The first element must be {@code Comparable}.
     *
     * @param other  the other pair
     * @return negative if this is less, zero if equal, positive if greater
     * @throws ClassCastException if the object is not comparable
     */
    @Override
    public int compareTo(ObjIntPair<A> other) {
        return ComparisonChain.start().compare((Comparable<?>) first, (Comparable<?>) other.first)
                .compare(second, other.second).result();
    }

    //-------------------------------------------------------------------------
    /**
     * Gets the pair using a standard string format.
     * <p>
     * The standard format is '[$first, $second]'. Spaces around the values are trimmed.
     *
     * @return the pair as a string
     */
    @Override
    public String toString() {
        return new StringBuilder().append('[').append(first).append(", ").append(second).append(']').toString();
    }

    /**
     * The serialization version id.
     */
    private static final long serialVersionUID = 1L;

    private ObjIntPair(A first, int second) {
        this.first = first;
        this.second = second;
    }

    //-----------------------------------------------------------------------
    /**
     * Gets the first element in this pair.
     * @return the value of the property, not null
     */
    public A getFirst() {
        return first;
    }

    //-----------------------------------------------------------------------
    /**
     * Gets the second element in this pair.
     * @return the value of the property
     */
    public int getSecond() {
        return second;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o)
            return true;
        if (o == null || getClass() != o.getClass())
            return false;

        ObjIntPair<?> that = (ObjIntPair<?>) o;

        if (second != that.second)
            return false;
        return first != null ? first.equals(that.first) : that.first == null;
    }

    @Override
    public int hashCode() {
        int result = first != null ? first.hashCode() : 0;
        result = 31 * result + second;
        return result;
    }
}