modules/core/src/main/java/org/apache/ignite/internal/util/nio/GridNioParser.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.ignite.internal.util.nio;

import java.io.IOException;
import java.nio.ByteBuffer;
import org.apache.ignite.IgniteCheckedException;
import org.jetbrains.annotations.Nullable;

/**
 * This interface declares a basic contract on message parsing and encoding to the underlying network layer.
 * <p>
 * Note that methods of this interface are called within NIO threads and should be as fast as possible. If
 * any of methods throw an exception, corresponding session will be closed and listener will be notified with
 * exception passed in as argument.
 */
public interface GridNioParser {
    /**
     * This method is called when input bytes are available on the underlying network connection.
     * <p>
     * Method must read given buffer until either it reaches the end of buffer or a valid user message
     * is encountered. In this case it must return parsed message.
     *
     * @param ses Session on which bytes are read.
     * @param buf Buffer that contains input data.
     * @return Parsed user message or {@code null} if complete message has not been received yet. Note
     *         that in case of returning {@code null} given buffer must be completely read.
     * @throws IOException If exception occurred while reading data.
     * @throws IgniteCheckedException If any user-specific error occurred.
     */
    @Nullable public Object decode(GridNioSession ses, ByteBuffer buf) throws IOException, IgniteCheckedException;

    /**
     * This method is called whenever a message should be sent to the network connection
     * and network buffer is ready to be filled with bytes.
     * <p>
     * Method must encode the complete message and return byte buffer from which data should be read.
     *
     * @param ses Session on which message is being sent.
     * @param msg Message to encode.
     * @return Buffer containing encoded message.
     * @throws IOException If exception occurred while encoding data.
     * @throws IgniteCheckedException If any user-specific error occurred while encoding data.
     */
    public ByteBuffer encode(GridNioSession ses, Object msg) throws IOException, IgniteCheckedException;
}