package java.awt;

import java.util.HashMap;
import java.util.Map;

class SchedulingEventQueue extends EventQueue
    {
      // Use Map< AWTEvent, List< AWTEvent > > to support multiple events
      private final Map< AWTEvent, AWTEvent > eventSchedule = new HashMap< AWTEvent, AWTEvent >();
      private boolean processing = false;

      public void scheduleEvent( final AWTEvent event, final AWTEvent dependentEvent )
      {
        eventSchedule.put( dependentEvent, event );
      }

      @Override
    protected void dispatchEvent(final AWTEvent event) {
        try {
            processing = true;
            super.dispatchEvent(event);
            processing = false;
        } finally {
            // Dispatch any dependent event
            AWTEvent scheduledEvent = eventSchedule.remove(event);
            if (scheduledEvent != null) {
                postEvent(scheduledEvent);
            }
        }
      }

      public boolean isEmpty() {
          return eventSchedule.isEmpty() && (!processing);
      }
    }