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javaprotocol-buffers

google protobuffer how to define list of lists in proto file?


I have a class with a list of lists field as below:

public class MyClass{
   private List<List<String>>
}

how to define it in a proto file?


Solution

    1. You can declare your own "types" in proto files called message.
    2. If you'd like to declare a list you should use repeated keyword.

    Combining those two gives us:

    message ListOfListsOfStrings {
        repeated ListOfStrings listOfStrings=1;
    }
    
    message ListOfStrings {
        repeated string strings=1;
    }
    

    You can then use ListOfListsOfStrings message in your proto were appropriate.