| /* |
| * Derby - Class org.apache.derbyTesting.functionTests.tests.engine.ModuleLoadingTest |
| * |
| * 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.derbyTesting.functionTests.tests.engine; |
| |
| import java.sql.Connection; |
| import java.sql.PreparedStatement; |
| import java.util.ArrayList; |
| import junit.framework.Test; |
| import org.apache.derbyTesting.junit.BaseJDBCTestCase; |
| import org.apache.derbyTesting.junit.BaseTestSuite; |
| import org.apache.derbyTesting.junit.JDBC; |
| import org.apache.derbyTesting.junit.TestConfiguration; |
| |
| /** |
| * This class contains tests for correct loading (booting) of modules |
| * and factories. |
| */ |
| public class ModuleLoadingTest extends BaseJDBCTestCase { |
| public ModuleLoadingTest(String name) { |
| super(name); |
| } |
| |
| public static Test suite() { |
| BaseTestSuite ts = new BaseTestSuite(); |
| |
| // Run concurrentLoadingOfSortFactory in a separate database so that |
| // the sort factory isn't already loaded. |
| ts.addTest(TestConfiguration.singleUseDatabaseDecorator( |
| new ModuleLoadingTest("concurrentLoadingOfSortFactory"))); |
| |
| return ts; |
| } |
| |
| /** |
| * Test case for DERBY-2074. When multiple threads tried to load |
| * ExternalSortFactory concurrently, we sometimes got a |
| * NullPointerException. |
| */ |
| public void concurrentLoadingOfSortFactory() throws Throwable { |
| // number of concurrent threads |
| final int numThreads = 10; |
| |
| // Helper object to make it easier to refer to ModuleLoadingTest.this |
| // from within the nested Runnable class. Used for synchronization |
| // between the threads. |
| final Object me = this; |
| |
| // Flag that tells the threads whether they're allowed to start. |
| final boolean[] go = new boolean[1]; |
| // Active threads count. |
| final int[] activeThreads = new int[1]; |
| // List of exceptions/throwables thrown by the forked threads. |
| final ArrayList<Throwable> exceptions = new ArrayList<Throwable>(); |
| |
| Thread[] threads = new Thread[numThreads]; |
| |
| // Start the threads. |
| for (int i = 0; i < numThreads; i++) { |
| final Connection c = openDefaultConnection(); |
| // Prepare a statement that ends up calling |
| // DistinctScalarAggregateResultSet.loadSorter(). |
| final PreparedStatement ps = c.prepareStatement( |
| "select count(distinct tablename) from sys.systables"); |
| threads[i] = new Thread(new Runnable() { |
| public void run() { |
| try { |
| _run(); |
| } catch (Throwable t) { |
| synchronized (me) { |
| exceptions.add(t); |
| } |
| } |
| } |
| private void _run() throws Exception { |
| synchronized (me) { |
| // Notify the main thread that we're ready to execute. |
| activeThreads[0]++; |
| me.notifyAll(); |
| |
| // Wait for the main thread to notify us that we |
| // should go ahead. |
| while (!go[0]) { |
| me.wait(); |
| } |
| } |
| // executeQuery() below used to get occational NPEs before |
| // DERBY-2074. |
| JDBC.assertDrainResults(ps.executeQuery()); |
| ps.close(); |
| c.close(); |
| } |
| }); |
| threads[i].start(); |
| } |
| |
| // We want all threads to execute the statement at the same time, |
| // so wait for all threads to be ready before giving them the GO |
| // signal. |
| synchronized (me) { |
| while (activeThreads[0] < numThreads && exceptions.isEmpty()) { |
| me.wait(); |
| } |
| |
| // All threads are active, or at least one of the threads have |
| // failed, so tell the threads to stop waiting. |
| go[0] = true; |
| me.notifyAll(); |
| } |
| |
| // The threads have been started, now wait for them to finish. |
| for (int i = 0; i < numThreads; i++) { |
| threads[i].join(); |
| } |
| |
| // At least one of the threads failed. Re-throw the first error |
| // reported. |
| if (!exceptions.isEmpty()) { |
| throw exceptions.get(0); |
| } |
| } |
| } |