provider/fastbin/src/main/java/org/apache/aries/rsa/provider/fastbin/io/ProtocolCodec.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you 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.apache.aries.rsa.provider.fastbin.io;

import java.io.IOException;
import java.nio.channels.ReadableByteChannel;
import java.nio.channels.WritableByteChannel;



/**
 * Interface to encode and decode commands in and out of a a non blocking channel.
 *
 */
public interface ProtocolCodec {

    ///////////////////////////////////////////////////////////////////
    //
    // Methods related with reading from the channel
    //
    ///////////////////////////////////////////////////////////////////

    /**
     * @param channel
     */
    public void setReadableByteChannel(ReadableByteChannel channel);

    /**
     * Non-blocking channel based decoding.
     * 
     * @return
     * @throws IOException
     */
    Object read() throws IOException;

    /**
     * @return The number of bytes received.
     */
    public long getReadCounter();


    ///////////////////////////////////////////////////////////////////
    //
    // Methods related with writing to the channel
    //
    ///////////////////////////////////////////////////////////////////


    enum BufferState {
        EMPTY,
        WAS_EMPTY,
        NOT_EMPTY,
        FULL,
    }

    public void setWritableByteChannel(WritableByteChannel channel);

    /**
     * Non-blocking channel based encoding.
     *
     * @return true if the write completed.
     * @throws IOException
     */
    BufferState write(Object value) throws IOException;

    /**
     * Attempts to complete the previous write which did not complete.
     * @return
     * @throws IOException
     */
    BufferState flush() throws IOException;

    /**
     * @return true if the codec will no accept any more writes.
     */
    boolean full();

    /**
     * @return The number of bytes written.
     */
    public long getWriteCounter();


}