/*

 * 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();

    }

}