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