test/jdk/java/nio/channels/AsynchronousChannelGroup/GroupOfOne.java

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * accompanied this code).
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 * 2 along with this work; if not, write to the Free Software Foundation,
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/* @test
 * @bug 4607272 6842687
 * @summary Unit test for AsynchronousChannelGroup
 */

import java.nio.ByteBuffer;
import java.nio.channels.*;
import java.net.*;
import java.util.*;
import java.util.concurrent.*;
import java.io.IOException;

/**
 * This test verifies that a channel or channel group can be closed from a
 * completion handler when there are no threads available to handle I/O events.
 */

public class GroupOfOne {

    public static void main(String[] args) throws Exception {
        final List<AsynchronousSocketChannel> accepted = new ArrayList<>();

        // create listener to accept connections
        try (final AsynchronousServerSocketChannel listener =
                AsynchronousServerSocketChannel.open()) {

            listener.bind(new InetSocketAddress(0));
            listener.accept((Void)null, new CompletionHandler<AsynchronousSocketChannel,Void>() {
                public void completed(AsynchronousSocketChannel ch, Void att) {
                    synchronized (accepted) {
                        accepted.add(ch);
                    }
                    listener.accept((Void)null, this);
                }
                public void failed(Throwable exc, Void att) {
                }
            });

            int port = ((InetSocketAddress)(listener.getLocalAddress())).getPort();
            SocketAddress sa = new InetSocketAddress(InetAddress.getLocalHost(), port);

            test(sa, true, false);
            test(sa, false, true);
            test(sa, true, true);
        } finally {
            // clean-up
            synchronized (accepted) {
                for (AsynchronousSocketChannel ch: accepted) {
                    ch.close();
                }
            }
        }
    }

    static void test(SocketAddress sa,
                     final boolean closeChannel,
                     final boolean shutdownGroup)
        throws Exception
    {
        // group with 1 thread
        final AsynchronousChannelGroup group = AsynchronousChannelGroup
            .withFixedThreadPool(1, new ThreadFactory() {
                @Override
                public Thread newThread(final Runnable r) {
                    return new Thread(r);
                }});
        final AsynchronousSocketChannel ch = AsynchronousSocketChannel.open(group);
        try {
            // the latch counts down when:
            // 1. The read operation fails (expected)
            // 2. the close/shutdown completes
            final CountDownLatch latch = new CountDownLatch(2);

            ch.connect(sa, (Void)null, new CompletionHandler<Void,Void>() {
                public void completed(Void result, Void att)  {
                    System.out.println("Connected");

                    // initiate I/O operation that does not complete (successfully)
                    ByteBuffer buf = ByteBuffer.allocate(100);
                    ch.read(buf, (Void)null, new CompletionHandler<Integer,Void>() {
                        public void completed(Integer bytesRead, Void att)  {
                            throw new RuntimeException();
                        }
                        public void failed(Throwable exc, Void att) {
                            if (!(exc instanceof AsynchronousCloseException))
                                throw new RuntimeException(exc);
                            System.out.println("Read failed (expected)");
                            latch.countDown();
                        }
                    });

                    // close channel or shutdown group
                    try {
                        if (closeChannel) {
                            System.out.print("Close channel ...");
                            ch.close();
                            System.out.println(" done.");
                        }
                        if (shutdownGroup) {
                            System.out.print("Shutdown group ...");
                            group.shutdownNow();
                            System.out.println(" done.");
                        }
                        latch.countDown();
                    } catch (IOException e) {
                        throw new RuntimeException();
                    }
                }
                public void failed(Throwable exc, Void att) {
                    throw new RuntimeException(exc);
                }
            });

            latch.await();
        } finally {
            // clean-up
            group.shutdown();
            boolean terminated = group.awaitTermination(20, TimeUnit.SECONDS);
            if (!terminated)
                throw new RuntimeException("Group did not terminate");
        }
        System.out.println("TEST OKAY");
    }
}