Java delete random elements

[john mater]

I have this code. I want to delete 25% of the ppdu elements at random before they are put in the queue, i know you cant give me the answers but i just need some help on how to start, thanks

  import java.util.concurrent.DelayQueue;
import java.util.concurrent.locks.ReentrantLock;
import java.util.*;

public class PhysicalLayer{
  DelayQueue<PPDU> queue = new DelayQueue<PPDU>();
    // queue to represent medium by holding PPDUs in transit
  private ReentrantLock lock = new ReentrantLock();
    // lock to block transmiting threads during transmission
  Random random = new Random(); 
  PhysicalLayer() {}
  


  void transmit(DPDU dpdu) throws InterruptedException {
    PPDU ppdu = new PPDU(dpdu);
    try {
      lock.lock(); // prevent concurrent transmission by different callers
      Thread.currentThread().sleep(8000*ppdu.length()/Globals.BANDWIDTH);
        // block caller until finished transmiting ppdu
      ppdu.setDelay(Globals.DELAY);
      queue.add(ppdu);
    } finally {
      lock.unlock();
    }

}
  DPDU receive() throws InterruptedException {
    PPDU ppdu = (PPDU)(queue.take()); // block caller until finished receiving ppdu
    DPDU dpdu = ppdu.getPayload();
    return dpdu;
  }
  
  
      
}  

(Edited code to make it not so wide -- PC)

[Paul Clapham]

Take the code which says "add to the queue" and replace it by something which does "with probability 0.75 add to the queue".

By the way I wouldn't call that "deleting", I would call it something more like "discarding" or "ignoring". There doesn't seem to be a place to delete the elements from, though.