How to restrict JTextField not taking more than 'x' numbers of inputs

I have a开发者_如何学Python JTextField. That takes in strings. For one JTextField, I want to limit to only two strings. For example 'fa' or '56' or '..' Not more than two.

Is there a way to do this?

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You can use a Formatted Text Field.

Or you can create a custom Document Filter.

Creating a custom Document is an old approach that is generally not used anymore.