code: public boolean tryEnterIf(Guard guard) {
      if (guard.monitor != this) {
        throw new IllegalMonitorStateException();
      }
      final ReentrantLock lock = this.lock;
      if (!lock.tryLock()) {
        return false;
      }
  
      boolean satisfied = false;
      try {
        return satisfied = guard.isSatisfied();
      } finally {
        if (!satisfied) {
          lock.unlock();
        }
      }
    }
docs: Enters this monitor if it is possible to do so immediately and the guard is satisfied. Does not
  block acquiring the lock and does not wait for the guard to be satisfied.
  
  <p><b>Note:</b> This method disregards the fairness setting of this monitor.
  
  @return whether the monitor was entered, which guarantees that the guard is now satisfied