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>An immutable triple consisting of three {@code Object} elements.</p>
021 * 
022 * <p>Although the implementation is immutable, there is no restriction on the objects
023 * that may be stored. If mutable objects are stored in the triple, then the triple
024 * itself effectively becomes mutable. The class is also {@code final}, so a subclass
025 * can not add undesirable behaviour.</p>
026 * 
027 * <p>#ThreadSafe# if all three objects are thread-safe</p>
028 *
029 * @param <L> the left element type
030 * @param <M> the middle element type
031 * @param <R> the right element type
032 *
033 * @version $Id: ImmutableTriple.java 1592817 2014-05-06 17:57:38Z britter $
034 * @since 3.2
035 */
036public final class ImmutableTriple<L, M, R> extends Triple<L, M, R> {
037
038    /** Serialization version */
039    private static final long serialVersionUID = 1L;
040
041    /** Left object */
042    public final L left;
043    /** Middle object */
044    public final M middle;
045    /** Right object */
046    public final R right;
047
048    /**
049     * <p>Obtains an immutable triple of from three objects inferring the generic types.</p>
050     * 
051     * <p>This factory allows the triple to be created using inference to
052     * obtain the generic types.</p>
053     * 
054     * @param <L> the left element type
055     * @param <M> the middle element type
056     * @param <R> the right element type
057     * @param left  the left element, may be null
058     * @param middle  the middle element, may be null
059     * @param right  the right element, may be null
060     * @return a triple formed from the three parameters, not null
061     */
062    public static <L, M, R> ImmutableTriple<L, M, R> of(final L left, final M middle, final R right) {
063        return new ImmutableTriple<L, M, R>(left, middle, right);
064    }
065
066    /**
067     * Create a new triple instance.
068     *
069     * @param left  the left value, may be null
070     * @param middle the middle value, may be null
071     * @param right  the right value, may be null
072     */
073    public ImmutableTriple(final L left, final M middle, final R right) {
074        super();
075        this.left = left;
076        this.middle = middle;
077        this.right = right;
078    }
079
080    //-----------------------------------------------------------------------
081    /**
082     * {@inheritDoc}
083     */
084    @Override
085    public L getLeft() {
086        return left;
087    }
088
089    /**
090     * {@inheritDoc}
091     */
092    @Override
093    public M getMiddle() {
094        return middle;
095    }
096
097    /**
098     * {@inheritDoc}
099     */
100    @Override
101    public R getRight() {
102        return right;
103    }
104}
105