    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one or more
    003 * contributor license agreements.  See the NOTICE file distributed with
    004 * this work for additional information regarding copyright ownership.
    005 * The ASF licenses this file to You under the Apache License, Version 2.0
    006 * (the "License"); you may not use this file except in compliance with
    007 * the License.  You may obtain a copy of the License at
    008 *
    009 *      http://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 * Unless required by applicable law or agreed to in writing, software
    012 * distributed under the License is distributed on an "AS IS" BASIS,
    013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 * See the License for the specific language governing permissions and
    015 * limitations under the License.
    016 */
    017package org.apache.commons.lang3.tuple;
    018
    019/**
    020 * <p>A mutable triple consisting of three {@code Object} elements.</p>
    021 *
    022 * <p>Not #ThreadSafe#</p>
    023 *
    024 * @param <L> the left element type
    025 * @param <M> the middle element type
    026 * @param <R> the right element type
    027 *
    028 * @since 3.2
    029 */
    030public class MutableTriple<L, M, R> extends Triple<L, M, R> {
    031
    032    /**
    033     * The empty array singleton.
    034     * <p>
    035     * Consider using {@link #emptyArray()} to avoid generics warnings.
    036     * </p>
    037     *
    038     * @since 3.10.
    039     */
    040    public static final MutableTriple<?, ?, ?>[] EMPTY_ARRAY = new MutableTriple[0];
    041
    042    /** Serialization version */
    043    private static final long serialVersionUID = 1L;
    044
    045    /**
    046     * Returns the empty array singleton that can be assigned without compiler warning.
    047     *
    048     * @param <L> the left element type
    049     * @param <M> the middle element type
    050     * @param <R> the right element type
    051     * @return the empty array singleton that can be assigned without compiler warning.
    052     *
    053     * @since 3.10.
    054     */
    055    @SuppressWarnings("unchecked")
    056    public static <L, M, R> MutableTriple<L, M, R>[] emptyArray() {
    057        return (MutableTriple<L, M, R>[]) EMPTY_ARRAY;
    058    }
    059
    060    /**
    061     * <p>Obtains a mutable triple of three objects inferring the generic types.</p>
    062     *
    063     * <p>This factory allows the triple to be created using inference to
    064     * obtain the generic types.</p>
    065     *
    066     * @param <L> the left element type
    067     * @param <M> the middle element type
    068     * @param <R> the right element type
    069     * @param left  the left element, may be null
    070     * @param middle  the middle element, may be null
    071     * @param right  the right element, may be null
    072     * @return a triple formed from the three parameters, not null
    073     */
    074    public static <L, M, R> MutableTriple<L, M, R> of(final L left, final M middle, final R right) {
    075        return new MutableTriple<>(left, middle, right);
    076    }
    077    /** Left object */
    078    public L left;
    079    /** Middle object */
    080    public M middle;
    081
    082    /** Right object */
    083    public R right;
    084
    085    /**
    086     * Create a new triple instance of three nulls.
    087     */
    088    public MutableTriple() {
    089        super();
    090    }
    091
    092    /**
    093     * Create a new triple instance.
    094     *
    095     * @param left  the left value, may be null
    096     * @param middle  the middle value, may be null
    097     * @param right  the right value, may be null
    098     */
    099    public MutableTriple(final L left, final M middle, final R right) {
    100        super();
    101        this.left = left;
    102        this.middle = middle;
    103        this.right = right;
    104    }
    105
    106    //-----------------------------------------------------------------------
    107    /**
    108     * {@inheritDoc}
    109     */
    110    @Override
    111    public L getLeft() {
    112        return left;
    113    }
    114
    115    /**
    116     * {@inheritDoc}
    117     */
    118    @Override
    119    public M getMiddle() {
    120        return middle;
    121    }
    122
    123    /**
    124     * {@inheritDoc}
    125     */
    126    @Override
    127    public R getRight() {
    128        return right;
    129    }
    130
    131    /**
    132     * Sets the left element of the triple.
    133     *
    134     * @param left  the new value of the left element, may be null
    135     */
    136    public void setLeft(final L left) {
    137        this.left = left;
    138    }
    139
    140    /**
    141     * Sets the middle element of the triple.
    142     *
    143     * @param middle  the new value of the middle element, may be null
    144     */
    145    public void setMiddle(final M middle) {
    146        this.middle = middle;
    147    }
    148
    149    /**
    150     * Sets the right element of the triple.
    151     *
    152     * @param right  the new value of the right element, may be null
    153     */
    154    public void setRight(final R right) {
    155        this.right = right;
    156    }
    157}
    158