替換字符串與枚舉枚舉生成自動protobuf的

Question

我枚舉原始的Java代碼：

public enum CarModel { 
    NOMODEL("NOMODEL"); 
    X("X"), 
    XS("XS"), 
    XSI("XS-I"); //NOTE the special - character. Can't be declared XS-I 
    XSI2("XS-I.2"); //NOTE the special . character. Can't be declared XS-I.2 
    private final String carModel; 
    CarModel(String carModel) { 
     this.carModel = carModel; 
    } 

    public String getCarModel() { return carModel; } 

    public static CarModel fromString(String text) { 
     if (text != null) { 
      for (CarModel c : CarModel.values()) { 
       if (text.equals(c.carModel)) { 
        return c; 
       } 
      } 
     } 
     return NOMODEL; //default 
    } 
} 

現在，如果我使用protobuf的，我得到的.proto文件：

enum CarModel { 
    NOMODEL = 0; 
    X = 1; 
    XS = 2; 
    XSI = 3; 
    XSI2 = 4; 
} 

從我earlier question我知道我可以調用由protoc生成的枚舉並刪除我自己的類（從而避免重複的值定義），但我仍然需要定義某處（在包裝類？包裝枚舉類？）備用fromString()方法將返回正確的字符串每枚枚舉。我怎麼做？

編輯： 如何實現如下：

String carModel = CarModel.XSI.toString(); 這將返回 「XS-I」

和：

CarModel carModel = CarModel.fromString("XS-I.2"); 

Answer 1

您可以使用Protobuf的"custom options"完成此操作。

import "google/protobuf/descriptor.proto"; 

option java_outer_classname = "MyProto"; 
// By default, the "outer classname" is based on the proto file name. 
// I'm declaring it explicitly here because I use it in the example 
// code below. Note that even if you use the java_multiple_files 
// option, you will need to use the outer classname in order to 
// reference the extension since it is not declared in a class. 

extend google.protobuf.EnumValueOptions { 
    optional string car_name = 50000; 
    // Be sure to read the docs about choosing the number here. 
} 

enum CarModel { 
    NOMODEL = 0 [(car_name) = "NOMODEL"]; 
    X = 1 [(car_name) = "X"]; 
    XS = 2 [(car_name) = "XS"]; 
    XSI = 3 [(car_name) = "XS-I"]; 
    XSI2 = 4 [(car_name) = "XS-I.2"]; 
} 

現在在Java中，你可以這樣做：

String name = 
    CarModel.XSI.getValueDescriptor() 
    .getOptions().getExtension(MyProto.carName); 
assert name.equals("XS-I"); 

https://developers.google.com/protocol-buffers/docs/proto#options（略微向下滾動到自定義選項的部分。）

Answer 2

CarModel carmodel = Enum.valueOf(CarModel.class, "XS") 

或

CarModel carmodel = CarModel.valueOf("XS");