/*

 * 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 4429043 6526860

 * @summary Test position method of FileChannel

 */

import java.io.*;

import java.nio.ByteBuffer;

import java.nio.channels.FileChannel;

import java.nio.file.*;

import static java.nio.file.StandardOpenOption.*;

import java.nio.charset.Charset;

import java.util.Random;

/**

 * Testing FileChannel's position method.

 */

public class Position {

    private static final Charset ISO8859_1 = Charset.forName("8859_1");

    private static final Random generator = new Random();

    public static void main(String[] args) throws Exception {

        Path blah = Files.createTempFile("blah", null);

        blah.toFile().deleteOnExit();

        initTestFile(blah);

        for (int i=0; i<10; i++) {

            try (FileChannel fc = (generator.nextBoolean()) ?

                    FileChannel.open(blah, READ) :

                    new FileInputStream(blah.toFile()).getChannel()) {

                for (int j=0; j<100; j++) {

                    long newPos = generator.nextInt(1000);

                    fc.position(newPos);

                    if (fc.position() != newPos)

                        throw new RuntimeException("Position failed");

                }

            }

        }

        for (int i=0; i<10; i++) {

            try (FileChannel fc = (generator.nextBoolean()) ?

                     FileChannel.open(blah, APPEND) :

                     new FileOutputStream(blah.toFile(), true).getChannel()) {

                for (int j=0; j<10; j++) {

                    if (fc.position() != fc.size())

                        throw new RuntimeException("Position expected to be size");

                    byte[] buf = new byte[generator.nextInt(100)];

                    fc.write(ByteBuffer.wrap(buf));

                }

            }

        }

        Files.delete(blah);

    }

    /**

     * Creates file blah:

     * 0000

     * 0001

     * 0002

     * 0003

     * .

     * .

     * .

     * 3999

     *

     */

    private static void initTestFile(Path blah) throws IOException {

        try (BufferedWriter awriter = Files.newBufferedWriter(blah, ISO8859_1)) {

            for(int i=0; i<4000; i++) {

                String number = new Integer(i).toString();

                for (int h=0; h<4-number.length(); h++)

                    awriter.write("0");

                awriter.write(""+i);

                awriter.newLine();

            }

        }

    }

}