Network Utilities

/**
 * Utility class for Netty 3 integration and buffer management
 */
public class Netty3Utils {
    /**
     * Default gathering flag for composite buffers to enable zero-copy operations
     */
    public static final boolean DEFAULT_GATHERING = true;
    
    /**
     * Sets up Netty 3 environment including logging configuration and thread naming.
     * Must be called before using any Netty 3 functionality.
     */
    public static void setup();
    
    /**
     * Converts Elasticsearch BytesReference to Netty ChannelBuffer for network transmission
     * @param bytes BytesReference containing data to convert
     * @return ChannelBuffer suitable for Netty operations
     */
    public static ChannelBuffer toChannelBuffer(BytesReference bytes);
    
    /**
     * Converts Netty ChannelBuffer to Elasticsearch BytesReference for internal processing
     * @param buffer ChannelBuffer containing network data
     * @return BytesReference for Elasticsearch internal use
     */
    public static BytesReference toBytesReference(ChannelBuffer buffer);
    
    /**
     * Converts Netty ChannelBuffer to Elasticsearch BytesReference with specified size
     * @param buffer ChannelBuffer containing network data
     * @param size Number of bytes to include in the conversion
     * @return BytesReference with the specified size
     */
    public static BytesReference toBytesReference(ChannelBuffer buffer, int size);
    
    /**
     * Closes a collection of Netty channels gracefully
     * @param channels Collection of Channel objects to close
     */
    public static void closeChannels(Collection<Channel> channels);
    
    /**
     * Handles fatal errors by rethrowing them on a separate thread to prevent blocking
     * @param t Throwable representing the fatal error
     */
    public static void maybeDie(Throwable t);
}

import org.elasticsearch.transport.netty3.Netty3Utils;
import org.elasticsearch.common.bytes.BytesReference;
import org.jboss.netty.buffer.ChannelBuffer;

// Setup Netty 3 environment (called automatically by plugin)
Netty3Utils.setup();

// Convert Elasticsearch bytes to Netty buffer for transmission
BytesReference elasticsearchData = // ... some data
ChannelBuffer nettyBuffer = Netty3Utils.toChannelBuffer(elasticsearchData);

// Convert received Netty buffer back to Elasticsearch bytes
ChannelBuffer receivedBuffer = // ... received from network
BytesReference elasticsearchBytes = Netty3Utils.toBytesReference(receivedBuffer);

// Convert with specific size limit
BytesReference limitedBytes = Netty3Utils.toBytesReference(receivedBuffer, 1024);

// Close multiple channels at once
List<Channel> channels = // ... collection of channels
Netty3Utils.closeChannels(channels);

/**
 * Handler for tracking and managing open Netty channels
 */
public class Netty3OpenChannelsHandler extends SimpleChannelUpstreamHandler implements Releasable {
    /**
     * Constructor for channel tracking handler
     * @param logger Logger instance for debugging and monitoring
     */
    public Netty3OpenChannelsHandler(Logger logger);
    
    /**
     * Handles upstream channel events for connection tracking
     * @param ctx Channel handler context
     * @param e Channel event to process
     */
    public void handleUpstream(ChannelHandlerContext ctx, ChannelEvent e);
    
    /**
     * Returns the current number of open channels
     * @return int count of currently open channels
     */
    public int numberOfOpenChannels();
    
    /**
     * Returns the total number of channels that have been created
     * @return long total channel count since startup
     */
    public long totalChannels();
    
    /**
     * Closes all currently tracked open channels
     */
    public void close();
}

/**
 * BytesReference implementation that wraps a Netty ChannelBuffer
 * Provides efficient access to network buffer data without copying
 */
public class ChannelBufferBytesReference implements BytesReference {
    /**
     * Constructor wrapping a ChannelBuffer with specified size
     * @param buffer ChannelBuffer to wrap
     * @param size Number of bytes to include from the buffer
     */
    public ChannelBufferBytesReference(ChannelBuffer buffer, int size);
    
    /**
     * Gets a single byte at the specified index
     * @param index Position to read from
     * @return byte value at the index
     */
    public byte get(int index);
    
    /**
     * Returns the total length of available data
     * @return int length in bytes
     */
    public int length();
    
    /**
     * Creates a slice of the buffer for the specified range
     * @param from Starting position (inclusive)
     * @param length Number of bytes to include
     * @return BytesReference containing the slice
     */
    public BytesReference slice(int from, int length);
    
    /**
     * Creates a stream input for reading the buffer data
     * @return StreamInput for sequential reading
     */
    public StreamInput streamInput();
    
    /**
     * Writes the buffer contents to an output stream
     * @param out OutputStream to write to
     */
    public void writeTo(OutputStream out);
}

/**
 * StreamInput implementation for reading from ChannelBuffer data
 */
public class ChannelBufferStreamInput extends StreamInput {
    /**
     * Constructor for creating stream input from ChannelBuffer
     * @param buffer ChannelBuffer containing data to read
     * @param size Number of bytes available for reading
     */
    public ChannelBufferStreamInput(ChannelBuffer buffer, int size);
    
    /**
     * Reads a single byte from the stream
     * @return int byte value (0-255) or -1 if end of stream
     */
    public int read();
    
    /**
     * Reads multiple bytes into a byte array
     * @param b Destination byte array
     * @param off Offset in the destination array
     * @param len Maximum number of bytes to read
     * @return int number of bytes actually read
     */
    public int read(byte[] b, int off, int len);
    
    /**
     * Resets the stream position to the beginning
     */
    public void reset();
    
    /**
     * Closes the stream and releases resources
     */
    public void close();
}

/**
 * Internal logger adapter for Netty 3 integration with Elasticsearch logging
 */
public class Netty3InternalESLogger implements InternalLogger {
    // Provides bridge between Netty 3 logging and Elasticsearch logging system
    // Handles log level mapping and message formatting
}

// The setup() method configures:
// - Netty 3 logging to use Elasticsearch's logging framework
// - Thread naming patterns for better debugging
// - System property configuration for optimal performance
// - Error handling integration

public static void setup() {
    // Configure Netty logging to use ES logging
    InternalLoggerFactory.setDefaultFactory(new Netty3InternalESLoggerFactory());
    
    // Set thread naming pattern for Netty threads
    System.setProperty("io.netty.threadLocalDirectBufferSize", /* optimized size */);
    
    // Additional Netty 3 system optimizations
    // ...
}