How to compare 2 Field Text with each other in Javafx

I have 2 Field Text in a BankAccount class, 1 for deposit, 1 to withdraw. Both of the field text take only double values:

TextField depositInput = new TextField();
TextField withdrawInput = new TextField();

And 1 button to execute these field texts (can be both).

Button button = new Button("Execute");

The problem is I don't know how to tell Java which TextField has been executed. Since I want to display different messages when the user wants to either deposit or withdraw:

For example:

if(FieldText executed is deposit){
    println("User deposits X amount");
    double depositAmount = X;

}

if(FieldText executed is withdraw){
    println("User withdraws X amount");
    double withdrawAmount = -X;
}