001/**
002 * Copyright (C) 2012 FuseSource, Inc.
003 * http://fusesource.com
004 *
005 * Licensed under the Apache License, Version 2.0 (the "License");
006 * you may not use this file except in compliance with the License.
007 * You may obtain a copy of the License at
008 *
009 *    http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018package org.fusesource.hawtdispatch.transport;
019
020import java.io.IOException;
021import java.nio.channels.ReadableByteChannel;
022import java.nio.channels.WritableByteChannel;
023
024
025/**
026 * Interface to encode and decode commands in and out of a a non blocking channel.
027 *
028 * @author <a href="http://hiramchirino.com">Hiram Chirino</a>
029 */
030public interface ProtocolCodec {
031
032    public void setTransport(Transport transport);
033
034    ///////////////////////////////////////////////////////////////////
035    //
036    // Methods related with reading from the channel
037    //
038    ///////////////////////////////////////////////////////////////////
039
040
041    /**
042     * Non-blocking channel based decoding.
043     * 
044     * @return
045     * @throws IOException
046     */
047    Object read() throws IOException;
048
049    /**
050     * Pushes back a buffer as being unread.
051     *
052     * @param buffer
053     */
054    void unread(byte[] buffer);
055
056    /**
057     * @return The number of bytes received.
058     */
059    public long getReadCounter();
060
061    /**
062     * @return The number of bytes read in the last read io performed.
063     */
064    public long getLastReadSize();
065
066
067    ///////////////////////////////////////////////////////////////////
068    //
069    // Methods related with writing to the channel
070    //
071    ///////////////////////////////////////////////////////////////////
072
073
074    enum BufferState {
075        EMPTY,
076        WAS_EMPTY,
077        NOT_EMPTY,
078        FULL,
079    }
080
081    public int getReadBufferSize();
082    public int getWriteBufferSize();
083
084    /**
085     * Non-blocking channel based encoding.
086     *
087     * @return true if the write completed.
088     * @throws IOException
089     */
090    BufferState write(Object value) throws IOException;
091
092    /**
093     * Attempts to complete the previous write which did not complete.
094     * @return
095     * @throws IOException
096     */
097    BufferState flush() throws IOException;
098
099    /**
100     * Is the codec's buffer full?
101     * @return
102     */
103    boolean full();
104
105    /**
106     * @return The number of bytes written.
107     */
108    public long getWriteCounter();
109
110    /**
111     * @return The number of bytes read in the last write io performed.
112     */
113    public long getLastWriteSize();
114
115}