19. Thread interruption - InterruptedException

• The InterruptedException is thrown when another thread interrupts the thread calling the blocking method

• Aa s general rule of thumb, an InterruptedException should cause the overall task of the thread to be cancelled

• It's generally best to set the thread's interrupted status again:

  
      public class MyRunnable implements Runnable() {
          public void run() {
              try {
                  doSomeWork();
              } catch ( InterruptedException iex ) {
              }
          }
  
          private void doSomeWork()
          {
              try {
                  // do the work
              } catch ( InterruptedException iex ) {
                  // We've been already interrupted here, but let
                  // the caller deal with it. To r re-throw the exception, we call
                  Thread.currentThread().interrupt();
                  // which sets the interrupt flag and re-throws the InterruptedException
              }
          }
      }//class MyRunnable
  
  

• Calling

  
      Thread.currentThread().interrupt();
  
  

  sets the interrupt flag of the current thread and will reraise the InterruptedException on it again. The caller of doSomeWork() the also gets a chance to examine the InterruptedException.

• Thus,

  
      Thread.currentThread().interrupt();
  
  

  is a better alternative to simply re-throwing the InterruptedException, because it preserves the interrupted state of the current thread.