How to make code run once inside background task looping?

Question

I have a background Task looping looks like this:

Timeline fiveSecondsWonder = new Timeline(new KeyFrame(Duration.seconds(1), event -> {
     if (hourNow >= cashCutOff_Start && hourNow <= cashCutOff_End - 1) {
//Run the code once
}
}));
fiveSecondsWonder.setCycleCount(Timeline.INDEFINITE);
fiveSecondsWonder.play();

This code does make loop every one second. But I want to make a single line of code executable once this code run.

Either create 2 separate `Timeline` or use a boolean variable to test inside to know if this part of code has run already — Kaddath, Mar 06 '19 at 10:00
Unrelated to your problem: please learn java naming conventions and stick to them. Related: it's rather unclear what you are after - please provide a [mcve] that demonstrates the problem and how it doesn't meet your requirements. — kleopatra, Mar 06 '19 at 10:07
underscores aren't the prettiest sight, but they are allowed (as per an interpretation of the conventions Oracle has https://www.oracle.com/technetwork/java/codeconventions-135099.html ) — Stultuske, Mar 06 '19 at 10:27
hehe, this variable name sure looks familiar: https://stackoverflow.com/questions/9966136/javafx-periodic-background-task/9966213#9966213 :D — Sergey Grinev, Mar 06 '19 at 11:07
@Stultuske don't see any statement in that document that suggests using underscores (except for constants which are all-caps, so have no other means to seperate words) .. obviously they are allowed by the language (otherwise the compiler would complain) but violating naming conventions ... repeating to drive it home — kleopatra, Mar 12 '19 at 10:08
@kleopatra all the guidelines state is that variable names shouldn't START with an underscore: "Variable names should not start with underscore _ or dollar sign $ characters, even though both are allowed." The problem with sentences like this in guidelines, is that they are a bit ambiguous and open for interpretation. — Stultuske, Mar 12 '19 at 10:10
@Stultuske no there is nothing open - they state clearly what you should do for separating out the words, and that's camel-case, nothing else. By convention, we should follow the affirmative sentences in conventions :) — kleopatra, Mar 12 '19 at 10:13

score 1 · Answer 1 · answered Mar 06 '19 at 11:07

1

Just remove fiveSecondsWonder.setCycleCount(Timeline.INDEFINITE);

answered Mar 06 '19 at 11:07

Sergey Grinev

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amarildo.xyz · Accepted Answer · 2019-03-06T10:20:25.477

Simple solution in two steps.

Create a boolean variable:

private boolean hasRun = false;

Add if statement in your Timeline:

Timeline fiveSecondsWonder = new Timeline(new KeyFrame(Duration.seconds(1), event -> {
    //check if code has run before
    if(!hasRun){
        //this will run only once
        //by setting hasRun = true;
        hasRun=true;
        //add your code here...
    }
    //this code will run in every KeyFrame
    //add your code here...
    }));
    fiveSecondsWonder.setCycleCount(Timeline.INDEFINITE);
    fiveSecondsWonder.play();

How to make code run once inside background task looping?

2 Answers2