Can I pass a Method as parameter of another method in java?

Question

I am trying to measure the execution time for several methods. so I was thinking to make a method instead of duplicate same code many times.

Here is my code:

Answer 1

I have a object call Counter which basically looks like this:

private long count;
private long errors;
private long duration;
private long errorDuration;

With two "time" methods for timing methods that return something and other methods which are void.

public  T time(ReturningRunnable runnable) {
    long start = currentTimeMillis();
    T result = null;
    try {
        result = runnable.run();
    } catch (Throwable ex) {
        errorDuration += currentTimeMillis() - start;
        errors++;
        throw runtime(ex);
    }
    duration += currentTimeMillis() - start;
    count++;
    return result;
}

public void time(Runnable runnable) {
    time(new RunnableRunner(runnable));
}

I chose to rethrow the exceptions as runtime exceptions (as i'm not a fan of checked exceptions) but you could just as well make your custom MyRunnable interface throw exceptions and just catch and re-throw them. Here's a usage of the above:

counter.time(new Runnable() {
    @Override
    public void run() {
        // Do something
    });

Or this, in the returning-value case:

return counter.time(new ReturningRunnable() {
    @Override
    public Integer run() {
        return 1; // You get the idea
    });

I like this because my counter objects can be exposed over JMX and injected wherever i need them. You could do what you've asked with reflection, but i think that would be messy (IMHO).