Java example source code file (Dispatcher1.java)

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Java - Java tags/keywords

dispatcher1, handler, ioexception, iterator, selectionkey, selector, util

The Dispatcher1.java Java example source code

/*
 * Copyright (c) 2004, 2011, Oracle and/or its affiliates. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 *   - Neither the name of Oracle nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * This source code is provided to illustrate the usage of a given feature
 * or technique and has been deliberately simplified. Additional steps
 * required for a production-quality application, such as security checks,
 * input validation and proper error handling, might not be present in
 * this sample code.
 */


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

/**
 * A single-threaded dispatcher.
 * <P>
 * When a SelectionKey is ready, it dispatches the job in this
 * thread.
 *
 * @author Mark Reinhold
 * @author Brad R. Wetmore
 */
class Dispatcher1 implements Dispatcher {

    private Selector sel;

    Dispatcher1() throws IOException {
        sel = Selector.open();
    }

    // Doesn't really need to be runnable
    public void run() {
        for (;;) {
            try {
                dispatch();
            } catch (IOException x) {
                x.printStackTrace();
            }
        }
    }

    private void dispatch() throws IOException {
        sel.select();
        for (Iterator i = sel.selectedKeys().iterator(); i.hasNext(); ) {
            SelectionKey sk = (SelectionKey)i.next();
            i.remove();
            Handler h = (Handler)sk.attachment();
            h.handle(sk);
        }
    }

    public void register(SelectableChannel ch, int ops, Handler h)
            throws IOException {
        ch.register(sel, ops, h);
    }
}