Page History

...

Message#writeTo consumes IgniteProductVersion of destination node and use it for serializing data for this version (mostly, for ignoring some fields).

Message#readFrom consumes IgniteProductVersion of source node and use it for deserializing data (mostly, for setting default values of new fields).

Code Block

language	java
title	Message

public interface Message {    
    public boolean writeTo(ByteBuffer buf, MessageWriter writer, IgniteProductVersion destVer);

    public boolean readFrom(ByteBuffer buf, MessageReader reader, IgniteProductVersion srcVer);

    public short directType();
}

Introduce annotations @Since and @Until for Message classes and Message fields, to use it for generating code for Message#writeTo and Message#readFrom:

Code Block

language	java
title	MyMessage

@Since(version = "2.19.0")
public class MyMessage {
    private int id;
    
    @Until(version = "2.20.0")
    private String rmFld;

    @Since(version = "2.20.0")
    private String newFld;

     @Override    @Override public boolean writeTo(ByteBuffer buf, MessageWriter writer, IgniteProductVersion destVer) {
        if (destVer.greaterThanEquallessThan(2, 19, 0))
            throw new IgniteException("Must not send the message to destination node");

        if (!writer.writeString(id))
            return false;

        if (destVer.lessThan(2, 20, 0)) {
            if (!writer.writeString(rmFld))
                return false;
        }

        if (destVer.greaterThanEqual(2, 20, 0)) {
            if (!writer.writeString(newFld))
                return false;
        }

        return true;
    }

    @Override public boolean readFrom(ByteBuffer buf, MessageReader reader, IgniteProductVersion srcVer) {
        id = reader.readString();

        if (srcVer.greaterThanEqual(2, 20, 0))
            newFld = reader.readString();
        else
            newFld = "default value";

        return true;
    }
}

Introduce Communication Protocol Version (ProtoVer) that depends on changes in the parts:

...

Page tree

Versions Compared

Old Version 2

New Version 3

Key