52 lines
1.5 KiB
Java
52 lines
1.5 KiB
Java
/* Copyright 2017 Andrew Dawson
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*
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* This file is a part of Tusky.
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*
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* This program is free software; you can redistribute it and/or modify it under the terms of the
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* GNU General Public License as published by the Free Software Foundation; either version 3 of the
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* License, or (at your option) any later version.
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*
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* Tusky is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even
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* the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
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* Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along with Tusky; if not,
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* see <http://www.gnu.org/licenses>. */
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package com.keylesspalace.tusky.util;
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/**
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* This is a synchronization primitive related to {@link java.util.concurrent.CountDownLatch}
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* except that it starts at zero and can count upward.
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* <p>
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* The intended use case is for waiting for all tasks to be finished when the number of tasks isn't
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* known ahead of time, or may change while waiting.
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*/
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public class CountUpDownLatch {
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private int count;
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public CountUpDownLatch() {
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this.count = 0;
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}
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public synchronized void countDown() {
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count--;
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notifyAll();
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}
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public synchronized void countUp() {
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count++;
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notifyAll();
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}
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public synchronized void await() throws InterruptedException {
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while (count != 0) {
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wait();
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}
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}
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public synchronized boolean isEmpty() {
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return count == 0;
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}
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}
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