Java tutorial
/* * Copyright 2015 Open Networking Laboratory * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.onlab.util; import org.apache.commons.lang.mutable.MutableBoolean; import org.junit.Ignore; import org.junit.Test; import java.util.concurrent.CountDownLatch; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; import java.util.concurrent.TimeUnit; import static org.junit.Assert.*; /** * Tests of the BlockingBoolean utility. */ public class BlockingBooleanTest { private static final int TIMEOUT = 100; //ms @Test public void basics() { BlockingBoolean b = new BlockingBoolean(false); assertEquals(false, b.get()); b.set(true); assertEquals(true, b.get()); b.set(true); assertEquals(true, b.get()); b.set(false); assertEquals(false, b.get()); } private void waitChange(boolean value, int numThreads) { BlockingBoolean b = new BlockingBoolean(!value); CountDownLatch latch = new CountDownLatch(numThreads); ExecutorService exec = Executors.newFixedThreadPool(numThreads); for (int i = 0; i < numThreads; i++) { exec.submit(() -> { try { b.await(value); latch.countDown(); } catch (InterruptedException e) { fail(); } }); } b.set(value); try { assertTrue(latch.await(TIMEOUT, TimeUnit.MILLISECONDS)); } catch (InterruptedException e) { fail(); } exec.shutdown(); } @Test public void waitTrueChange() { waitChange(true, 4); } @Test public void waitFalseChange() { waitChange(false, 4); } @Test public void waitSame() { BlockingBoolean b = new BlockingBoolean(true); CountDownLatch latch = new CountDownLatch(1); ExecutorService exec = Executors.newSingleThreadExecutor(); exec.submit(() -> { try { b.await(true); latch.countDown(); } catch (InterruptedException e) { fail(); } }); try { assertTrue(latch.await(TIMEOUT, TimeUnit.MILLISECONDS)); } catch (InterruptedException e) { fail(); } exec.shutdown(); } @Test public void someWait() { BlockingBoolean b = new BlockingBoolean(false); int numThreads = 4; CountDownLatch sameLatch = new CountDownLatch(numThreads / 2); CountDownLatch waitLatch = new CountDownLatch(numThreads / 2); ExecutorService exec = Executors.newFixedThreadPool(numThreads); for (int i = 0; i < numThreads; i++) { final boolean value = (i % 2 == 1); exec.submit(() -> { try { b.await(value); if (value) { waitLatch.countDown(); } else { sameLatch.countDown(); } } catch (InterruptedException e) { fail(); } }); } try { assertTrue(sameLatch.await(TIMEOUT, TimeUnit.MILLISECONDS)); assertEquals(waitLatch.getCount(), numThreads / 2); } catch (InterruptedException e) { fail(); } b.set(true); try { assertTrue(waitLatch.await(TIMEOUT, TimeUnit.MILLISECONDS)); } catch (InterruptedException e) { fail(); } exec.shutdown(); } @Test public void waitTimeout() { BlockingBoolean b = new BlockingBoolean(true); CountDownLatch latch = new CountDownLatch(1); ExecutorService exec = Executors.newSingleThreadExecutor(); exec.submit(() -> { try { if (!b.await(false, 1, TimeUnit.NANOSECONDS)) { latch.countDown(); } else { fail(); } } catch (InterruptedException e) { fail(); } }); try { assertTrue(latch.await(TIMEOUT, TimeUnit.MILLISECONDS)); } catch (InterruptedException e) { fail(); } exec.shutdown(); } @Test @Ignore public void samePerf() { int iters = 10_000; BlockingBoolean b1 = new BlockingBoolean(false); long t1 = System.nanoTime(); for (int i = 0; i < iters; i++) { b1.set(false); } long t2 = System.nanoTime(); MutableBoolean b2 = new MutableBoolean(false); for (int i = 0; i < iters; i++) { b2.setValue(false); } long t3 = System.nanoTime(); System.out.println((t2 - t1) + " " + (t3 - t2) + " " + ((t2 - t1) <= (t3 - t2))); } @Test @Ignore public void changePerf() { int iters = 10_000; BlockingBoolean b1 = new BlockingBoolean(false); boolean v = true; long t1 = System.nanoTime(); for (int i = 0; i < iters; i++) { b1.set(v); v = !v; } long t2 = System.nanoTime(); MutableBoolean b2 = new MutableBoolean(false); for (int i = 0; i < iters; i++) { b2.setValue(v); v = !v; } long t3 = System.nanoTime(); System.out.println((t2 - t1) + " " + (t3 - t2) + " " + ((t2 - t1) <= (t3 - t2))); } }