/*
 * Controller.java February 2008
 *
 * Copyright (C) 2008, Niall Gallagher <niallg@users.sf.net>
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or 
 * implied. See the License for the specific language governing 
 * permissions and limitations under the License.
 */

package org.simpleframework.transport;

import java.io.IOException;

/**
 * The <code>Controller</code> interface is used to represent the means to write
 * packets to an underlying transport. This controls all of the selection
 * required to determine if the socket is write ready. If the packet to be
 * written is to block then this will wait until all queued packets are fully
 * written.
 * 
 * @author Niall Gallagher
 */
interface Controller {

    /**
     * This method is used to deliver the provided packet of bytes to the
     * underlying transport. This will not modify the data that is to be
     * written, this will simply queue the packets in the order that they are
     * provided.
     * 
     * @param packet
     *            this is the packet to send to the client
     */
    void write(Packet packet) throws IOException;

    /**
     * This method is used to flush all of the queued packets to the client.
     * This method will block not block but will simply flush any data to the
     * underlying transport. Internally the data will be queued for delivery to
     * the connected entity.
     */
    void flush() throws IOException;

    /**
     * This is used to close the writer and the underlying socket. If a close is
     * performed on the writer then no more bytes can be read from or written to
     * the writer and the client will receive a connection close on their side.
     */
    void close() throws IOException;

}