001/*
002 * PlotSquared, a land and world management plugin for Minecraft.
003 * Copyright (C) IntellectualSites <https://intellectualsites.com>
004 * Copyright (C) IntellectualSites team and contributors
005 *
006 * This program is free software: you can redistribute it and/or modify
007 * it under the terms of the GNU General Public License as published by
008 * the Free Software Foundation, either version 3 of the License, or
009 * (at your option) any later version.
010 *
011 * This program is distributed in the hope that it will be useful,
012 * but WITHOUT ANY WARRANTY; without even the implied warranty of
013 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
014 * GNU General Public License for more details.
015 *
016 * You should have received a copy of the GNU General Public License
017 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
018 */
019package com.plotsquared.core.util.task;
020
021/**
022 * A task that can be run and cancelled (if repeating)
023 */
024public interface PlotSquaredTask extends Runnable {
025
026    /**
027     * Get a new {@link NullTask}
028     *
029     * @return Null task instance
030     */
031    static NullTask nullTask() {
032        return new NullTask();
033    }
034
035    /**
036     * Run the task. Don't override this, instead
037     * implement {@link #runTask()}
038     */
039    @Override
040    default void run() {
041        if (isCancelled()) {
042            return;
043        }
044        this.runTask();
045    }
046
047    /**
048     * Run the task
049     */
050    void runTask();
051
052    /**
053     * Check if the task has been cancelled
054     *
055     * @return {@code true} if the tasks is cancelled,
056     *         {@code false} if not
057     */
058    boolean isCancelled();
059
060    /**
061     * Cancel the task
062     */
063    void cancel();
064
065    /**
066     * Task that does nothing and is always cancelled
067     */
068    class NullTask implements PlotSquaredTask {
069
070        @Override
071        public void runTask() {
072        }
073
074        @Override
075        public boolean isCancelled() {
076            return true;
077        }
078
079        @Override
080        public void cancel() {
081        }
082
083    }
084
085}