/*

 * Copyright (c) 2015, 2018, 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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

import java.io.Closeable;

import java.io.IOException;

import java.nio.ByteBuffer;

import java.nio.channels.ClosedChannelException;

/*

 * I/O abstraction used to implement WebSocket.

 *

 * @since 9

 */

public interface RawChannel extends Closeable {

    interface Provider {

        RawChannel rawChannel() throws IOException;

    }

    interface RawEvent {

        /*

         * Returns the selector op flags this event is interested in.

         */

        int interestOps();

        /*

         * Called when event occurs.

         */

        void handle();

    }

    /*

     * Registers given event whose callback will be called once only (i.e.

     * register new event for each callback).

     *

     * Memory consistency effects: actions in a thread calling registerEvent

     * happen-before any subsequent actions in the thread calling event.handle

     */

    void registerEvent(RawEvent event) throws IOException;

    /**

     * Hands over the initial bytes. Once the bytes have been returned they are

     * no longer available and the method will throw an {@link

     * IllegalStateException} on each subsequent invocation.

     *

     * @return the initial bytes

     * @throws IllegalStateException

     *         if the method has been already invoked

     */

    ByteBuffer initialByteBuffer() throws IllegalStateException;

    /*

     * Returns a ByteBuffer with the data read or null if EOF is reached. Has no

     * remaining bytes if no data available at the moment.

     */

    ByteBuffer read() throws IOException;

    /*

     * Writes a sequence of bytes to this channel from a subsequence of the

     * given buffers.

     */

    long write(ByteBuffer[] srcs, int offset, int length) throws IOException;

    /**

     * Shutdown the connection for reading without closing the channel.

     *

     * <p> Once shutdown for reading then further reads on the channel will

     * return {@code null}, the end-of-stream indication. If the input side of

     * the connection is already shutdown then invoking this method has no

     * effect.

     *

     * @throws ClosedChannelException

     *         If this channel is closed

     * @throws IOException

     *         If some other I/O error occurs

     */

    void shutdownInput() throws IOException;

    /**

     * Shutdown the connection for writing without closing the channel.

     *

     * <p> Once shutdown for writing then further attempts to write to the

     * channel will throw {@link ClosedChannelException}. If the output side of

     * the connection is already shutdown then invoking this method has no

     * effect.

     *

     * @throws ClosedChannelException

     *         If this channel is closed

     * @throws IOException

     *         If some other I/O error occurs

     */

    void shutdownOutput() throws IOException;

    /**

     * Closes this channel.

     *

     * @throws IOException

     *         If an I/O error occurs

     */

    @Override

    void close() throws IOException;

}