FlatBuffersX

FlatBuffer code generator

generate code[json2flat flat2json bean2flat or flat2bean] by java file produce by flatc.

Feature

• Java Bean to flatbuffers
• Java Bean to Json
• Json to Java Bean
• flatbuffers to Java Bean

Usage

annotationProcessor 'io.flatbufferx:flatbufferx-compiler:last-version"

Require

flatc version >=1.9.0

usage

public final class UserFB extends FlatBufferMapper<UserFB> {
  public Long id;

  public String login;

  @Override
  public UserFB parse(JsonParser jsonParser) throws IOException {
//...
    return instance;
  }

  @Override
  public void parseField(UserFB instance, String fieldName, JsonParser jsonParser) throws
      IOException {
    if ("id".equals(fieldName)) {
      instance.id = jsonParser.getCurrentToken() == JsonToken.VALUE_NULL ? null : Long.valueOf(jsonParser.getValueAsLong());
    } else if ("login".equals(fieldName)) {
      instance.login = jsonParser.getValueAsString(null);
    }
  }

  @Override
  public void serialize(UserFB object, JsonGenerator jsonGenerator, boolean writeStartAndEnd) throws
      IOException {
    if (writeStartAndEnd) {
      jsonGenerator.writeStartObject();
    }
    if (object.id != null) {
      jsonGenerator.writeNumberField("id", object.id);
    }
    if (object.login != null) {
      jsonGenerator.writeStringField("login", object.login);
    }
    if (writeStartAndEnd) {
      jsonGenerator.writeEndObject();
    }
  }

  @Override
  public ByteBuffer toFlatBuffer(UserFB object) throws IOException {
    FlatBufferBuilder bufferBuilder = new FlatBufferBuilder();
  //....
    return bufferBuilder.dataBuffer();
  }

  @Override
  public int toFlatBufferOffset(FlatBufferBuilder bufferBuilder) throws IOException {
    return User.createUser(bufferBuilder,bufferBuilder.createString(this.login),this.id);
  }

  @Override
  public UserFB flatBufferToBean(Object object) throws IOException {
    User flatObj = (User) object;
    this.id = flatObj.id();
    this.login = flatObj.login();
    return this;
  }
}

• flatBufferToBean

  • covert flat object to java bean object

• toFlatBufferOffset

  • append java bean to flatbuffers,you should not call it directly

• toFlatBuffer

  • convert java bean to flatbuffer for data exchange

  performance

  	FlatBuffers (binary)	Protocol Buffers LITE	Rapid JSON	FlatBuffers (JSON)	pugixml	Raw structs
  Decode + Traverse + Dealloc (1 million times, seconds)	0.08	302	583	105	196	0.02
  Decode / Traverse / Dealloc (breakdown)	0 / 0.08 / 0	220 / 0.15 / 81	294 / 0.9 / 287	70 / 0.08 / 35	41 / 3.9 / 150	0 / 0.02 / 0
  Encode (1 million times, seconds)	3.2	185	650	169	273	0.15
  Wire format size (normal / zlib, bytes)	344 / 220	228 / 174	1475 / 322	1029 / 298	1137 / 341	312 / 187
  Memory needed to store decoded wire (bytes / blocks)	0 / 0	760 / 20	65689 / 4	328 / 1	34194 / 3	0 / 0
  Transient memory allocated during decode (KB)	0	1	131	4	34	0
  Generated source code size (KB)	4	61	0	4	0	0
  Field access in handwritten traversal code	typed accessors	typed accessors	manual error checking	typed accessors	manual error checking	typed but no safety
  Library source code (KB)	15	some subset of 3800	87	43	327	0