Question

Is it possible to create a method that times another method by reference in Java?

I’m thinking of something like:

  int timeMethod(method myMethod) {
        long start = time
        run myMethod
        long end = time
        return end-start
     }

Answer 1

You can wrap your method call in a Runnable and time how long it takes the Runnable to run:

long timeMethod(Runnable myMethodRunner) {
    long start = System.nanoTime();
    myMethodRunner.run();
    return System.nanoTime() - start;
}

Then you can time your method as follows:

public void myMethod(...) {
    . . .
}

// later:

long timeInNanoSeconds = timeMethod(new Runnable() {
    public void run() {
        myMethod(...);
    }
});