/* * Copyright (c) 2018-2028, DreamLu All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * Neither the name of the dreamlu.net developer nor the names of its * contributors may be used to endorse or promote products derived from * this software without specific prior written permission. * Author: DreamLu 卢春梦 (596392912@qq.com) */ package org.springblade.core.tool.tuple; import lombok.*; /** * tuple Pair * * @author L.cm **/ @Getter @ToString @EqualsAndHashCode public class Pair { private static final Pair EMPTY = new Pair<>(null, null); private final L left; private final R right; /** * Returns an empty pair. */ @SuppressWarnings("unchecked") public static Pair empty() { return (Pair) EMPTY; } /** * Constructs a pair with its left value being {@code left}, or returns an empty pair if * {@code left} is null. * * @return the constructed pair or an empty pair if {@code left} is null. */ public static Pair createLeft(L left) { if (left == null) { return empty(); } else { return new Pair<>(left, null); } } /** * Constructs a pair with its right value being {@code right}, or returns an empty pair if * {@code right} is null. * * @return the constructed pair or an empty pair if {@code right} is null. */ public static Pair createRight(R right) { if (right == null) { return empty(); } else { return new Pair<>(null, right); } } public static Pair create(L left, R right) { if (right == null && left == null) { return empty(); } else { return new Pair<>(left, right); } } private Pair(L left, R right) { this.left = left; this.right = right; } }