/*

 * 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.

 *

 */

/* @test

 * @bug 4607272 6842687

 * @summary Unit test for AsynchronousChannelGroup

 */

import java.nio.ByteBuffer;

import java.nio.channels.*;

import java.net.*;

import java.util.concurrent.*;

import java.io.IOException;

public class Unbounded {

    // number of concurrent completion handlers

    static final int CONCURRENCY_COUNT = 256;

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

        // all accepted connections are added to a queue

        final ArrayBlockingQueue<AsynchronousSocketChannel> queue =

            new ArrayBlockingQueue<AsynchronousSocketChannel>(CONCURRENCY_COUNT);

        // create listener to accept connections

        final AsynchronousServerSocketChannel listener =

            AsynchronousServerSocketChannel.open()

                .bind(new InetSocketAddress(0));

        listener.accept((Void)null, new CompletionHandler<AsynchronousSocketChannel,Void>() {

            public void completed(AsynchronousSocketChannel ch, Void att) {

                queue.add(ch);

                listener.accept((Void)null, this);

            }

            public void failed(Throwable exc, Void att) {

            }

        });

        System.out.println("Listener created.");

        // establish lots of connections

        int port = ((InetSocketAddress)(listener.getLocalAddress())).getPort();

        SocketAddress sa = new InetSocketAddress(InetAddress.getLocalHost(), port);

        AsynchronousSocketChannel[] channels =

            new AsynchronousSocketChannel[CONCURRENCY_COUNT];

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

            int attempts = 0;

            for (;;) {

                try {

                    channels[i] = AsynchronousSocketChannel.open();

                    channels[i].connect(sa).get();

                    break;

                } catch (IOException x) {

                    // probably resource issue so back off and retry

                    if (++attempts >= 3)

                        throw x;

                    Thread.sleep(50);

                }

            }

        }

        System.out.println("All connection established.");

        // the barrier where all threads (plus the main thread) wait

        final CyclicBarrier barrier = new CyclicBarrier(CONCURRENCY_COUNT+1);

        // initiate a read operation on each channel.

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

            ByteBuffer buf = ByteBuffer.allocateDirect(100);

            channels[i].read( buf, channels[i],

                new CompletionHandler<Integer,AsynchronousSocketChannel>() {

                    public void completed(Integer bytesRead, AsynchronousSocketChannel ch) {

                        try {

                            ch.close();

                            barrier.await();

                        } catch (Exception x) {

                            throw new AssertionError(x);

                        }

                    }

                    public void failed(Throwable exc, AsynchronousSocketChannel ch) {

                    }

                });

        }

        System.out.println("All read operations outstanding.");

        // write data to each of the accepted connections

        int remaining = CONCURRENCY_COUNT;

        while (remaining > 0) {

            AsynchronousSocketChannel ch = queue.take();

            ch.write(ByteBuffer.wrap("welcome".getBytes())).get();

            ch.close();

            remaining--;

        }

        // wait for all threads to reach the barrier

        System.out.println("Waiting for all threads to reach barrier");

        barrier.await();

        listener.close();

    }

}