subprotocol.java

import static FieldType.*;
public enum MCPEProtocolInfoV27{
	LOGIN_PACKET(
		LoginRequest.class,
		new PF(STRING, "username"),
		new PF(LONG, "clientId")
	);
	MCPEProtocolInfoV27(Class<? extends Request> requestClass, PF... fields){
		// initialize fields
	}
}
public class PF{
	public FieldType type;
	public String name;
	public PF(FieldType type, String name){
		this.type = type;
		this.name = name;
	}
}
public enum FieldType{
	STRING{
		@Override public Object read(Buffer buffer){
			byte[] bytes = new byte[buffer.getShort()];
			buffer.read(bytes);
			return new String(bytes);
		}
		@Override public void write(Buffer buffer, Object param){
			buffer.write(params.getBytes());
		}
	},
	BLAH,
	BLAH,
	BLAH;
	public abstract void write(Buffer buffer, Object param);
	public abstract Object read(Buffer buffer);
}