Quadruple.java

/*
 * 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 com.service.misc;

import org.apache.commons.lang3.builder.CompareToBuilder;

import java.io.Serializable;
import java.util.Objects;

/**
 * A quadruple consisting of four elements
 * @author Uri Loya
 * @param <L> the left element type
 * @param <ML> the middle left element type
 * @param <MR> the middle right element type
 * @param <R> the right element type
 */
public abstract class Quadruple<L, ML, MR, R> implements Comparable<Quadruple<L, ML, MR, R>>, Serializable {
    private static final class QuadrupleAdapter<L, ML, MR, R> extends Quadruple<L, ML, MR, R> {

        private static final long serialVersionUID = 1L;

        @Override
        public L getLeft() {
            return null;
        }

        @Override
        public ML getMiddleLeft() {
            return null;
        }

        @Override
        public MR getMiddleRight() {
            return null;
        }

        @Override
        public R getRight() {
            return null;
        }

    }

    /** Serialization version */
    private static final long serialVersionUID = 1L;

    /**
     * An empty array.
     * <p>
     * Consider using {@link #emptyArray()} to avoid generics warnings.
     * </p>
     */
    public static final Quadruple<?, ?, ?, ?>[] EMPTY_ARRAY = new Quadruple.QuadrupleAdapter[0];

    /**
     * Returns the empty array singleton that can be assigned without compiler warning.
     *
     * @param <L> the left element type
     * @param <ML> the middle left element type
     * @param <MR> the middle right element type
     * @param <R> the right element type
     * @return the empty array singleton that can be assigned without compiler warning.
     */
    @SuppressWarnings("unchecked")
    public static <L, ML, MR, R> Quadruple<L, ML, MR, R>[] emptyArray() {
        return (Quadruple<L, ML, MR, R>[]) EMPTY_ARRAY;
    }

    /**
     * <p>Obtains an immutable Quadruple of three objects inferring the generic types.</p>
     *
     * <p>This factory allows the Quadruple to be created using inference to
     * obtain the generic types.</p>
     *
     * @param <L> the left element type
     * @param <ML> the middle left element type
     * @param <MR> the middle right element type
     * @param <R> the right element type
     * @param left  the left element, may be null
     * @param middleLeft the middle left element, may be null
     * @param middleRight the middle right element, may be null
     * @param right  the right element, may be null
     * @return a Quadruple formed from the three parameters, not null
     */
    public static <L, ML, MR, R> Quadruple<L, ML, MR, R> of(final L left, final ML middleLeft, final MR middleRight, final R right) {
        return new ImmutableQuadruple<>(left, middleLeft, middleRight, right);
    }

    //-----------------------------------------------------------------------
    /**
     * <p>Compares the Quadruple based on the left element, followed by the middle element,
     * finally the right element.
     * The types must be {@code Comparable}.</p>
     *
     * @param other the other Quadruple, not null
     * @return negative if this is less, zero if equal, positive if greater
     */
    @Override
    public int compareTo(final Quadruple<L, ML, MR, R> other) {
        return new CompareToBuilder().append(getLeft(), other.getLeft())
                .append(getMiddleLeft(), other.getMiddleLeft())
                .append(getMiddleRight(), other.getMiddleRight())
                .append(getRight(), other.getRight()).toComparison();
    }

    /**
     * <p>Compares this Quadruple to another based on the three elements.</p>
     *
     * @param obj  the object to compare to, null returns false
     * @return true if the elements of the Quadruple are equal
     */
    @Override
    public boolean equals(final Object obj) {
        if (obj == this) {
            return true;
        }
        if (obj instanceof Quadruple<?, ?, ?, ?>) {
            final Quadruple<?, ?, ?, ?> other = (Quadruple<?, ?, ?, ?>) obj;
            return Objects.equals(getLeft(), other.getLeft())
                    && Objects.equals(getMiddleLeft(), other.getMiddleLeft())
                    && Objects.equals(getMiddleRight(), other.getMiddleRight())
                    && Objects.equals(getRight(), other.getRight());
        }
        return false;
    }

    //-----------------------------------------------------------------------
    /**
     * <p>Gets the left element from this Quadruple.</p>
     *
     * @return the left element, may be null
     */
    public abstract L getLeft();

    /**
     * <p>Gets the middle left element from this Quadruple.</p>
     *
     * @return the middle left element, may be null
     */
    public abstract ML getMiddleLeft();

    /**
     * <p>Gets the middle right element from this Quadruple.</p>
     *
     * @return the middle right element, may be null
     */
    public abstract MR getMiddleRight();

    /**
     * <p>Gets the right element from this Quadruple.</p>
     *
     * @return the right element, may be null
     */
    public abstract R getRight();

    /**
     * <p>Returns a suitable hash code.</p>
     *
     * @return the hash code
     */
    @Override
    public int hashCode() {
        return (getLeft() == null ? 0 : getLeft().hashCode()) ^
                (getMiddleLeft() == null ? 0 : getMiddleLeft().hashCode()) ^
                (getMiddleRight() == null ? 0 : getMiddleRight().hashCode()) ^
                (getRight() == null ? 0 : getRight().hashCode());
    }

    /**
     * <p>Returns a String representation of this Quadruple using the format {@code ($left,$middleLeft,$middleRight,$right)}.</p>
     *
     * @return a string describing this object, not null
     */
    @Override
    public String toString() {
        return "(" + getLeft() + "," + getMiddleLeft() + "," + getMiddleRight() + "," + getRight() + ")";
    }

    /**
     * <p>Formats the receiver using the given format.</p>
     *
     * <p>This uses {@link java.util.Formattable} to perform the formatting. Three variables may
     * be used to embed the left and right elements. Use {@code %1$s} for the left
     * element, {@code %2$s} for the middle left, {@code %3$s} for the middle right and {@code %4$s} for the right element.
     * The default format used by {@code toString()} is {@code (%1$s,%2$s,%3$s,%4$s)}.</p>
     *
     * @param format  the format string, optionally containing {@code %1$s}, {@code %2$s}, {@code %3$s} and {@code %4$s}, not null
     * @return the formatted string, not null
     */
    public String toString(final String format) {
        return String.format(format, getLeft(), getMiddleLeft(), getMiddleRight(), getRight());
    }

}