Question

I have an object containing a list sent from a C# client to a Java server. The serialization with protobuf work perfectly and the object is received perfectly in Java. But the class generated with protoc.exe (can we call it a proto class?) have a list that i can’t modify. Basically, I have to add some values in it before returning it to C#, but when I try to add a value, i have an exception :

Exception in thread "main" java.lang.UnsupportedOperationException
    at java.util.AbstractList.add(AbstractList.java:148)
    at java.util.AbstractList.add(AbstractList.java:108)
    ...

Here’s how i’m adding values:

MyProtoObject.MyResult result = MyProtoObject.MyResut.NewBuilder()
        .setId(1)
        .setValue(9.135)
        .build();
MyObject.getResultList().add(result);

How can i insert values in it?

Answer 1

Ok after regenerating the proto class, it appears some methods was missing (I probably made mistakes in first generation). So now i can add values in the list :

MyObjectProto.MyObject o = MyObjectProto.MyObject.newBuilder()
    .addAllResults(listOfCalculations)
    .build();

listOfCalculation is a List of results objects

or just :

MyObjectProto.MyObject o = MyObjectProto.MyObject.newBuilder()
    .addResult(calculationResult)
    .build();

CalculationResult is a single result object

Thanks to Flavio