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    }
090
091    /**
092     * Create a new triple instance.
093     *
094     * @param left  the left value, may be null
095     * @param middle  the middle value, may be null
096     * @param right  the right value, may be null
097     */
098    public MutableTriple(final L left, final M middle, final R right) {
099        this.left = left;
100        this.middle = middle;
101        this.right = right;
102    }
103
104    //-----------------------------------------------------------------------
105    /**
106     * {@inheritDoc}
107     */
108    @Override
109    public L getLeft() {
110        return left;
111    }
112
113    /**
114     * {@inheritDoc}
115     */
116    @Override
117    public M getMiddle() {
118        return middle;
119    }
120
121    /**
122     * {@inheritDoc}
123     */
124    @Override
125    public R getRight() {
126        return right;
127    }
128
129    /**
130     * Sets the left element of the triple.
131     *
132     * @param left  the new value of the left element, may be null
133     */
134    public void setLeft(final L left) {
135        this.left = left;
136    }
137
138    /**
139     * Sets the middle element of the triple.
140     *
141     * @param middle  the new value of the middle element, may be null
142     */
143    public void setMiddle(final M middle) {
144        this.middle = middle;
145    }
146
147    /**
148     * Sets the right element of the triple.
149     *
150     * @param right  the new value of the right element, may be null
151     */
152    public void setRight(final R right) {
153        this.right = right;
154    }
155}
156