Netty Integration

This guide shows how to integrate FastProto with Netty to encode/decode objects from/to ByteBuf.

Dependency

Add the Netty dependency in your application (FastProto itself declares it as provided):

<dependency>
  <groupId>io.netty</groupId>
  <artifactId>netty-all</artifactId>
  <version>4.1.x</version>
</dependency>

Codecs

• Inbound: FastProtoDecoder<T> converts ByteBuf to a target object.
• Outbound: FastProtoEncoder converts an object to ByteBuf.
• Both can be annotated with @Sharable and reused across channels.

Framing (fixed length, length-field, delimiter-based, etc.) should be handled by Netty.

Example: Fixed 60-Byte Frame

ch.pipeline()
  .addLast(new FixedLengthFrameDecoder(60))
  .addLast(new FastProtoDecoder<>(MyPojo.class))
  .addLast(new FastProtoEncoder());

MyPojo is a FastProto-annotated class. Example 60-byte layout:

public class MyPojo {
  @Int32Type(offset = 0) int id;
  @Int64Type(offset = 4) long timestamp;
  @StringType(offset = 12, length = 16) String name;
  @BinaryType(offset = 28, length = 32) byte[] payload;
}

Multiple Types

• Use a dedicated "type field" in the frame and route in an inbound handler.
• Alternatively, bind a type per-channel and construct FastProtoDecoder<>(Type.class) accordingly.

Zero-Copy (Optional)

Current implementation copies ByteBuf to byte[]. A zero-copy path can be added later to read directly from ByteBuf.

Testing

Use EmbeddedChannel for unit tests:

EmbeddedChannel ch = new EmbeddedChannel(
  new FixedLengthFrameDecoder(60),
  new FastProtoDecoder<>(MyPojo.class),
  new FastProtoEncoder()
);