An easier way of setting nested properties values in Grpc generated java code

Question

We are using Grpc with our java apps and we have a nested object defined in protobuff.

example of the proto:

message Person {
  string name = 1;
  Child child = 2; 
}

message Child {
  string name = 1;
  Hobby hobbies = 2;
}

message Hobby {
  string name = 1;
  string reason = 2;
}

When I want to update the reason for the child's hobby I have to do something like:

person.toBuilder()
.setChild(
    person.getChild.toBuilder()
        .setHobby(
            person.getChild().getHobby().toBuilder()
                .setReason("new reason")
                .build()
        )
        .build()
)
.build()

The code above is not the nicest and my question is if there is any better way to accomplish the same?

Answer 1

TL;DR

Person.Builder builder = person.toBuilder();
builder.getChildBuilder().getHobbyBuilder().setReason("new reason");
Person personWithUpdatedReason = builder.build();

Details: Better way is subjective, what are you expectations? I believe, something along the lines of:

person.getChild().getHobby().setReason("new reason");

If that's the case, you'd want the object to be mutable, which, depending upon the context, may not be a good thing.

Another example:

Hobby newHobby = person.getChild().getHobby().toBuilder().setReason("new reason").build();
Child newChild = person.getChild().toBuilder().setHobby(newHobby).toBuild();
Person newPerson = person.toBuilder().setChild(newChild).toBuild();

return newPerson;

This is better if only you don't like your code to have multi-level nesting.

Unfortunately, I don't think I helped you, rather interested to know what you/others think of this.

I read a bit more on this, and the official docs do suggest a better way: https://developers.google.com/protocol-buffers/docs/reference/java-generated?csw=1#sub-builders

So you can write you code something like this:

Person.Builder builder = person.toBuilder();
builder.getChildBuilder().getHobbyBuilder().setReason("new reason");
Person personWithUpdatedReason = builder.build();