135 lines
4.4 KiB
Java
135 lines
4.4 KiB
Java
/*
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* Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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/**
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* @test
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* @bug 5073414
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* @summary Ensure that there is no race condition in BufferedReader.readLine()
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* when a line is terminated by '\r\n' is read by multiple threads.
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*/
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import java.io.*;
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import java.util.concurrent.TimeUnit;
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import java.util.concurrent.ExecutorService;
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import java.util.concurrent.Executors;
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public class ReadLineSync {
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public static int lineCount = 0;
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public static void main( String[] args ) throws Exception {
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String dir = System.getProperty(".", ".");
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File f = new File(dir, "test.txt");
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createFile(f);
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f.deleteOnExit();
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BufferedReader reader = new BufferedReader(
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new FileReader(f));
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try {
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int threadCount = 2;
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ExecutorService es = Executors.newFixedThreadPool(threadCount);
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for (int i=0; i < threadCount; i++)
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es.execute(new BufferedReaderConsumer(reader));
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// Wait for the tasks to complete
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es.shutdown();
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while (!es.awaitTermination(60, TimeUnit.SECONDS));
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} finally {
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reader.close();
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}
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}
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static class BufferedReaderConsumer extends Thread {
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BufferedReader reader;
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public BufferedReaderConsumer( BufferedReader reader ) {
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this.reader = reader;
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}
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public void run() {
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try {
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String record = reader.readLine();
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if ( record == null ) {
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// if the first thread is too fast the second will hit
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// this which is ok
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System.out.println( "File already finished" );
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return;
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}
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if ( record.length() == 0 ) {
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// usually it comes out here indicating the first read
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// done by the second thread to run failed
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System.out.println("Empty string on first read." +
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Thread.currentThread().getName() );
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}
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while ( record != null ) {
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lineCount++;
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// Verify the token count
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if ( record.length() == 0 ) {
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// very occasionally it will fall over here
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throw new Exception( "Invalid tokens with string '" +
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record + "' on line " + lineCount );
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}
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record = reader.readLine();
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}
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}
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catch ( Exception e ) {
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e.printStackTrace();
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}
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}
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}
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// Create a relatively big file
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private static void createFile(File f) throws IOException {
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BufferedWriter w = new BufferedWriter(
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new FileWriter(f));
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int count = 10000;
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while (count > 0) {
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w.write("abcd \r\n");
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w.write("efg \r\n");
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w.write("hijk \r\n");
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w.write("lmnop \r\n");
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w.write("qrstuv \r\n");
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w.write("wxy and z \r\n");
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w.write("now you \r\n");
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w.write("know your \r\n");
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w.write("abc \r\n");
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w.write("next time \r\n");
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w.write("want you \r\n");
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w.write("sing with me \r\n");
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count--;
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}
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w.close();
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}
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}
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