code: @Override
      public boolean matches(Object arg0) {
          if (!super.matches(arg0)) {
              return false;
          }
          Event event = (Event) arg0;
          return eventIds == null || eventIds.contains(event.getId());
      }
docs: Checks if the given argument is an <code>Event</code> with one of the
  specified event ids.
  
  @param arg0
  an <code>Event</code>.
  @return <code>true</code> if the given argument is an
  <code>Event</code> with one of the specified event ids,
  <code>false</code> if the given argument is <code>null</code>,
  not an <code>Event</code>, or is an <code>Event</code> but
  has a different event id.
  @see org.drools.spi.ObjectType#matches(java.lang.Object)