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Java example source code file (BackgroundInitializerTest.java)
The BackgroundInitializerTest.java Java example source code/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You 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.apache.commons.lang3.concurrent; import org.junit.Test; import static org.junit.Assert.*; import java.util.concurrent.CountDownLatch; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; import java.util.concurrent.TimeUnit; import java.util.concurrent.atomic.AtomicReference; public class BackgroundInitializerTest { /** * Helper method for checking whether the initialize() method was correctly * called. start() must already have been invoked. * * @param init the initializer to test */ private void checkInitialize(final BackgroundInitializerTestImpl init) { try { final Integer result = init.get(); assertEquals("Wrong result", 1, result.intValue()); assertEquals("Wrong number of invocations", 1, init.initializeCalls); assertNotNull("No future", init.getFuture()); } catch (final ConcurrentException cex) { fail("Unexpected exception: " + cex); } } /** * Tests whether initialize() is invoked. */ @Test public void testInitialize() { final BackgroundInitializerTestImpl init = new BackgroundInitializerTestImpl(); init.start(); checkInitialize(init); } /** * Tries to obtain the executor before start(). It should not have been * initialized yet. */ @Test public void testGetActiveExecutorBeforeStart() { final BackgroundInitializerTestImpl init = new BackgroundInitializerTestImpl(); assertNull("Got an executor", init.getActiveExecutor()); } /** * Tests whether an external executor is correctly detected. */ @Test public void testGetActiveExecutorExternal() throws InterruptedException { final ExecutorService exec = Executors.newSingleThreadExecutor(); try { final BackgroundInitializerTestImpl init = new BackgroundInitializerTestImpl( exec); init.start(); assertSame("Wrong executor", exec, init.getActiveExecutor()); checkInitialize(init); } finally { exec.shutdown(); exec.awaitTermination(1, TimeUnit.SECONDS); } } /** * Tests getActiveExecutor() for a temporary executor. */ @Test public void testGetActiveExecutorTemp() { final BackgroundInitializerTestImpl init = new BackgroundInitializerTestImpl(); init.start(); assertNotNull("No active executor", init.getActiveExecutor()); checkInitialize(init); } /** * Tests the execution of the background task if a temporary executor has to * be created. */ @Test public void testInitializeTempExecutor() { final BackgroundInitializerTestImpl init = new BackgroundInitializerTestImpl(); assertTrue("Wrong result of start()", init.start()); checkInitialize(init); assertTrue("Executor not shutdown", init.getActiveExecutor() .isShutdown()); } /** * Tests whether an external executor can be set using the * setExternalExecutor() method. */ @Test public void testSetExternalExecutor() { final ExecutorService exec = Executors.newCachedThreadPool(); try { final BackgroundInitializerTestImpl init = new BackgroundInitializerTestImpl(); init.setExternalExecutor(exec); assertEquals("Wrong executor service", exec, init .getExternalExecutor()); assertTrue("Wrong result of start()", init.start()); assertSame("Wrong active executor", exec, init.getActiveExecutor()); checkInitialize(init); assertFalse("Executor was shutdown", exec.isShutdown()); } finally { exec.shutdown(); } } /** * Tests that setting an executor after start() causes an exception. * * @throws org.apache.commons.lang3.concurrent.ConcurrentException because the test implementation may throw it */ @Test public void testSetExternalExecutorAfterStart() throws ConcurrentException, InterruptedException { final BackgroundInitializerTestImpl init = new BackgroundInitializerTestImpl(); init.start(); ExecutorService exec = Executors.newSingleThreadExecutor(); try { init.setExternalExecutor(exec); fail("Could set executor after start()!"); } catch (final IllegalStateException istex) { init.get(); } finally { exec.shutdown(); exec.awaitTermination(1, TimeUnit.SECONDS); } } /** * Tests invoking start() multiple times. Only the first invocation should * have an effect. */ @Test public void testStartMultipleTimes() { final BackgroundInitializerTestImpl init = new BackgroundInitializerTestImpl(); assertTrue("Wrong result for start()", init.start()); for (int i = 0; i < 10; i++) { assertFalse("Could start again", init.start()); } checkInitialize(init); } /** * Tests calling get() before start(). This should cause an exception. * * @throws org.apache.commons.lang3.concurrent.ConcurrentException because the test implementation may throw it */ @Test(expected=IllegalStateException.class) public void testGetBeforeStart() throws ConcurrentException { final BackgroundInitializerTestImpl init = new BackgroundInitializerTestImpl(); init.get(); } /** * Tests the get() method if background processing causes a runtime * exception. */ @Test public void testGetRuntimeException() { final BackgroundInitializerTestImpl init = new BackgroundInitializerTestImpl(); final RuntimeException rex = new RuntimeException(); init.ex = rex; init.start(); try { init.get(); fail("Exception not thrown!"); } catch (final Exception ex) { assertEquals("Runtime exception not thrown", rex, ex); } } /** * Tests the get() method if background processing causes a checked * exception. */ @Test public void testGetCheckedException() { final BackgroundInitializerTestImpl init = new BackgroundInitializerTestImpl(); final Exception ex = new Exception(); init.ex = ex; init.start(); try { init.get(); fail("Exception not thrown!"); } catch (final ConcurrentException cex) { assertEquals("Exception not thrown", ex, cex.getCause()); } } /** * Tests the get() method if waiting for the initialization is interrupted. * * @throws java.lang.InterruptedException because we're making use of Java's concurrent API */ @Test public void testGetInterruptedException() throws InterruptedException { final ExecutorService exec = Executors.newSingleThreadExecutor(); final BackgroundInitializerTestImpl init = new BackgroundInitializerTestImpl( exec); final CountDownLatch latch1 = new CountDownLatch(1); init.shouldSleep = true; init.start(); final AtomicReference<InterruptedException> iex = new AtomicReference Other Java examples (source code examples)Here is a short list of links related to this Java BackgroundInitializerTest.java source code file: |
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