Understanding Java notation

Question

I am trying to use dialogs in Android. In the process, I encountered lines of code like the following:

alertDialogBuilder
            .setMessage("Click yes to exit!")
            .setCancelable(false)
            .setPositiveButton("Yes",new...

This notation is a bit strange for me as an old C++ programmer. Is this the same as,

alertDialogBuilder.setMessage("Click yes to exit!");
alertDialogBuilder.setCancelable(false);
alertDialogBuilder.setPositiveButton("Yes",new...

If so, is this notation part of Java or unique to Android programming? What is the name of this notation (or method)?

Answer 1

This idiom is called method chaining and it's not specific to Java or Android. The trick is making methods that otherwise would return void return a reference to this, permitting long chains of method calls to the same object.

This idiom is quite useful when used in the builder pattern, like in your example. It's also a building block when designing fluent interfaces.

Answer 2

You can do same with C++ as well just return same object (this pointer). So ultimately you are calling next function on returned this pointer.

It is used in Builder Design Pattern!