My command can't be used with ConditionalCommand

Technical Java
#1

In another command file, if I write:
new ConditionalCommand(new DriveTimed(.5, -.25, .25), new DriveTimed(.5, .25, -.25), Robot.getTurn()::get)
the DriveTimed() calls are underlined and it says that the constructor for ConditionalCommand() only takes (Command, Command, boolean). Any idea why DriveTimed() doesn’t count as a command?

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#2

Here’s the autonomous where I call it:

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#3

Why do you not just put the two DriveBase(leftPower,rightPower).withTimeout(timeout) command into the ConditionalCommand?

#4

You can’t mix the old command framework with the new one. You need to delete all references to the old command framework from your code; your command is probably implemented on top of the v1 base class.

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#5

just found out drivetimed isn’t the problem, but the condition is. When it says the 3rd param needs to be a “condition”, can’t I just put in a boolean or put ::get next to a boolean?

#6

You can’t just put in a boolean, because the condition has to be evaluated at scheduling time, not at command construction. You have to give it a method that returns a boolean.

Unfortunately, Java is not such a powerful language that you can do boolean::get (if only!). You’ll have to write a lambda expression.

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#7

According to the documentation, the last parameter needs to be a BooleanSupplier. A BooleanSupplier is a function having no argument as input, and returning a boolean as output.

If Robot.getTurn() is the condition you want to use, the conditional command can be written like this:

new ConditionalCommand(new DriveTimed(.5, -.25, .25), new DriveTimed(.5, .25, -.25), Robot::getTurn);

Key points:

  • Robot is the robot instance for which getTurn is going to be invoked on
  • Robot::getTurn is called a method reference

If you need additional logic, a BooleanSupplier can be created using a lamba expression (e.g. if the condition is Robot.getTurn() must be greater than 5, then this could do the trick:

new ConditionalCommand(new DriveTimed(.5, -.25, .25), new DriveTimed(.5, .25, -.25), () -> { return Robot.getTurn() > 5; });

The last parameter is called a lambda expression. It can be used to declare a BooleanSupplier:
e.g. BooleanSupplier supplier = () -> { return Robot.getTurn() > 5; };

I hope this helps.

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