package tutor;

import java.util.*;

/** The Task interface represents any kind of activity
 *  which may take some significant time. Tasks may succeed 
 *  or fail. A Task may have begun but not finished. In the {@linkplain tutor}
 *  package a task is used by the {@linkplain TaskManager} class,
 *  which queues a list of tasks and carries them out in a 
 *  Thread.
 *  
 *  An example of a Task is a {@linkplain tutor.SoundDownload}
 *
 */

public interface Task
{
  //--------------------------------------------
  /** begin the task whatever it is */
  void begin(); 
  //--------------------------------------------
  /** reports if the task has finished or not */
  boolean hasFinished();
  //--------------------------------------------
  /** returns the amount of time which the task took to 
   *  complete, in milliseconds */
  long getWorkDuration();
  //--------------------------------------------
  /** the amount of time taken to complete in seconds */
  float getWorkDurationInSeconds();
  //--------------------------------------------
  Date getStartTime();
  //--------------------------------------------
  Date getFinishTime();
  //--------------------------------------------
  /** reports if the task was completed successfully */
  boolean wasSuccessful();
  //--------------------------------------------
  /** return a string describing the result of the task. This
   *  should return something like 'success', 'failure' or 
   *  'not started' */
  String getResult();
  //--------------------------------------------
  /** prints a concise report about the state and result of 
   *  the task */
  String print(); 
  //--------------------------------------------
  /** prints a more comprehensive report about the state and
   *  result of the task */
  String printReport(); 
} //-- Task