load method calls another method at the end in Java

Question

I have an abstract class Task with two methods execute() and finish() as the following:

abstract class Task {
  abstract void execute();

  private void finish() {
    // Do something...
  }
}

How can I ensure that the overloaded method execute() in subclasses of Task implicitly calls finish() as the last statement?

Answer 1

You can create a ExecutorCloseable class that implements the [AutoCloseable] interface, such as:

public class ExecutorCloseable extends Foo implements AutoCloseable 
{
  @Override
  public void execute() 
  {
    // ...
  }

  @Override           //this one comes from AutoCloseable
  public void close() //<--will be called after execute is finished
  {
     super.finish();
  }
 }

You could call it this way (silly main() example):

 public static void main(String[] args) 
 {
     try (ExecutorCloseable ec = new ExecutorCloseable ()) 
     {

        ec.execute();

     } catch(Exception e){
        //...
     } finally {
       //...
    }
 }

Hope it makes sense, I can't really know how you call these methods nor how you create the classes. But hey, it's a try : )

For this to work, the finish() method on Foo should be protected or public (first one recommended), though.