How do I pass a function as a parameter

Question

I have a class called RigidBody and it has an update function.
And in there you shift the horizontal axis and a function is called to handle and check horizontal collisions and the same for the vertical axis. Now each entity that has a RigidBody component has a custom handleHorizontalCollisions() and handleVerticalCollisions() which I will need to pass in. How do I pass functions?

Here is what I am trying to do:

By the way “dt” stands for delta time. My game is not frame capped. And “Velocity” is a member of RigidBody.

public void update(float dt, Vector position, function handleHorizontalCollisions, function handleVerticalCollisions) {
position.x += velocity.x * dt;

handleHorizontalCollisions();

position.y += velocity.y * dt;

handleVerticalCollisions();
}

Answer 1

Frumkin

You can not pass a function as a parameter in java. You can just call the function inside another function using object.

That's why Java is object oriented programming language.

Answer 2

+ For simpler functions is sometimes better to use lambda expressions as parameter.
Also there is complicated way how to invoke Method object by the reflect API.