/*

 * Copyright (c) 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

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 * 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.nio.ByteBuffer;

import java.nio.channels.CompletionHandler;

/**

 * Handles a cycle of reading / writing on the {@code Client}.

 */

class ClientReader {

    private final DataReader callback;

    private final ChatServer chatServer;

    ClientReader(ChatServer chatServer, DataReader callback) {

        this.chatServer = chatServer;

        this.callback = callback;

    }

    public boolean acceptsMessages() {

        return callback.acceptsMessages();

    }

    /**

     * Runs a cycle of doing a beforeRead action and then enqueuing a new

     * read on the client. Handles closed channels and errors while reading.

     * If the client is still connected a new round of actions are called.

     */

    public void run(final Client client) {

        callback.beforeRead(client);

        client.read(new CompletionHandler<Integer, ByteBuffer>() {

            @Override

            public void completed(Integer result, ByteBuffer buffer) {

                // if result is negative or zero the connection has been closed or something gone wrong

                if (result < 1) {

                    client.close();

                    System.out.println("Closing connection to " + client);

                    chatServer.removeClient(client);

                } else {

                    callback.onData(client, buffer, result);

                    // enqueue next round of actions

                    client.run();

                }

            }

            @Override

            public void failed(Throwable exc, ByteBuffer buffer) {

                client.close();

                chatServer.removeClient(client);

            }

        });

    }

}