test/java/nio/channels/Selector/LotsOfChannels.java

/*
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * 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
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 *
 * 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).
 *
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 * 2 along with this work; if not, write to the Free Software Foundation,
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/* @test
 * @bug 4503092
 * @summary Tests that Windows Selector can use more than 63 channels
 * @run main/timeout=300 LotsOfChannels
 * @author kladko
 */

import java.net.*;
import java.io.*;
import java.nio.*;
import java.nio.channels.*;

public class LotsOfChannels {

    private final static int PIPES_COUNT = 1900;
    private final static int BUF_SIZE = 8192;
    private final static int LOOPS = 10;

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


        String os = System.getProperty("os.name");
        if (!(os.equals("Windows NT")
           || os.equals("Windows 2000")
           || os.equals("Windows XP")))
            return;

        Pipe[] pipes = new Pipe[PIPES_COUNT];
        Pipe pipe = Pipe.open();
        Pipe.SinkChannel sink = pipe.sink();
        Pipe.SourceChannel source = pipe.source();
        Selector sel = Selector.open();
        source.configureBlocking(false);
        source.register(sel, SelectionKey.OP_READ);

        for (int i = 0; i< PIPES_COUNT; i++ ) {
            pipes[i]= Pipe.open();
            Pipe.SourceChannel sc = pipes[i].source();
            sc.configureBlocking(false);
            sc.register(sel, SelectionKey.OP_READ);
            Pipe.SinkChannel sc2 = pipes[i].sink();
            sc2.configureBlocking(false);
            sc2.register(sel, SelectionKey.OP_WRITE);
        }

        for (int i = 0 ; i < LOOPS; i++ ) {
            sink.write(ByteBuffer.allocate(BUF_SIZE));
            int x = sel.selectNow();
            sel.selectedKeys().clear();
            source.read(ByteBuffer.allocate(BUF_SIZE));
        }
        sel.close();
    }
}