/*

 * Copyright (c) 2008, 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 6448457

 * @summary Test Channels.newOutputStream returns OutputStream that handles

 *     short writes from the underlying channel

 * @key randomness

 */

import java.io.OutputStream;

import java.io.IOException;

import java.nio.ByteBuffer;

import java.nio.channels.*;

import java.util.Random;

public class ShortWrite {

    static Random rand = new Random();

    static int bytesWritten = 0;

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

        WritableByteChannel wbc = new WritableByteChannel() {

            public int write(ByteBuffer src) {

                int rem = src.remaining();

                if (rem > 0) {

                    // short write

                    int n = rand.nextInt(rem) + 1;

                    src.position(src.position() + n);

                    bytesWritten += n;

                    return n;

                } else {

                    return 0;

                }

            }

            public void close() throws IOException {

                throw new RuntimeException("not implemented");

            }

            public boolean isOpen() {

                throw new RuntimeException("not implemented");

            }

        };

        // wrap Channel with OutputStream

        OutputStream out = Channels.newOutputStream(wbc);

        // write 100, 99, 98, ... 1

        // and check that the expected number of bytes is written

        int expected = 0;

        byte[] buf = new byte[100];

        for (int i=0; i<buf.length; i++) {

            int len = buf.length-i;

            out.write(buf, i, len);

            expected += len;

        }

        System.out.format("Bytes written: %d, expected: %d\n", bytesWritten,

            expected);

        if (bytesWritten != expected)

            throw new RuntimeException("incorrect number of bytes written");

    }

}