Question:
I want to capture an event that signals a user’s completed update to a TextField.

Answer:
In general, a user will finish entering text in a TextField by pressing the enter key. This generates an ActionEvent. It sounds like that’s all you need to catch. Although if you wanted to, you could add a key listener to your TextField, and monitor keystrokes until the enter key was pressed. Alternatively, you could require theuser to press a button to indicate completion. You’ve got a lot of options. Choose the one that fits your situation best.