/*
 * Copyright (c) 2008, 2010, 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.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * 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
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 */

package sun.nio.ch;

import java.nio.channels.*;
import java.nio.channels.spi.AsynchronousChannelProvider;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.ThreadFactory;
import java.io.IOException;

public class LinuxAsynchronousChannelProvider
    extends AsynchronousChannelProvider
{
    private static volatile EPollPort defaultPort;

    private EPollPort defaultEventPort() throws IOException {
        if (defaultPort == null) {
            synchronized (LinuxAsynchronousChannelProvider.class) {
                if (defaultPort == null) {
                    defaultPort = new EPollPort(this, ThreadPool.getDefault()).start();
                }
            }
        }
        return defaultPort;
    }

    public LinuxAsynchronousChannelProvider() {
    }

    @Override
    public AsynchronousChannelGroup openAsynchronousChannelGroup(int nThreads, ThreadFactory factory)
        throws IOException
    {
        return new EPollPort(this, ThreadPool.create(nThreads, factory)).start();
    }

    @Override
    public AsynchronousChannelGroup openAsynchronousChannelGroup(ExecutorService executor, int initialSize)
        throws IOException
    {
        return new EPollPort(this, ThreadPool.wrap(executor, initialSize)).start();
    }

    private Port toPort(AsynchronousChannelGroup group) throws IOException {
        if (group == null) {
            return defaultEventPort();
        } else {
            if (!(group instanceof EPollPort))
                throw new IllegalChannelGroupException();
            return (Port)group;
        }
    }

    @Override
    public AsynchronousServerSocketChannel openAsynchronousServerSocketChannel(AsynchronousChannelGroup group)
        throws IOException
    {
        return new UnixAsynchronousServerSocketChannelImpl(toPort(group));
    }

    @Override
    public AsynchronousSocketChannel openAsynchronousSocketChannel(AsynchronousChannelGroup group)
        throws IOException
    {
        return new UnixAsynchronousSocketChannelImpl(toPort(group));
    }
}
