A GWT menu bar that closes itself if user interaction ceases.

SelfClosingMenuBar.java

package cazcade.boardcast.client.main.widgets;

import com.google.gwt.event.dom.client.MouseOutEvent;
import com.google.gwt.user.client.Event;
import com.google.gwt.user.client.Timer;
import com.google.gwt.user.client.ui.MenuBar;
import com.google.gwt.user.client.ui.MenuItem;

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

/**
 * @author <a href="http://uk.linkedin.com/in/neilellis">Neil Ellis</a>
 */
public class SelfClosingMenuBar extends MenuBar {
    public static final  int                 GENERAL_TIMEOUT  = 4000;
    public static final  int                 PARENT_TIMEOUT   = 10000;
    public static final  int                 LEAF_OUT_TIMEOUT = 500;

    private static final Map<MenuBar, Timer> timers           = new HashMap<MenuBar, Timer>();
    private final MenuBar root;
    private       boolean hasSubmenus;

    public SelfClosingMenuBar(boolean vertical, MenuBar root) {
        super(vertical);
        this.root = root;
        setAutoOpen(false);
    }

    @Override protected void onLoad() {
        super.onLoad();
        if (getClose() == null) {
            setClose(new Timer() {
                @Override public void run() {
                    root.closeAllChildren(false);
                }
            });
        }

        List<MenuItem> items = getItems();
        for (MenuItem item : items) {
            if (item.getSubMenu() != null) {
                hasSubmenus = true;
            }
        }
        if (!hasSubmenus) {
            startCloseTimer(GENERAL_TIMEOUT);
        }
    }

    @Override public void onBrowserEvent(Event event) {
        super.onBrowserEvent(event);
        cancelCloseTimer();
        if (event.getType().equals(MouseOutEvent.getType().getName()) && !hasSubmenus) {
            startCloseTimer(LEAF_OUT_TIMEOUT);
        } else {
            startCloseTimer(hasSubmenus ? PARENT_TIMEOUT : GENERAL_TIMEOUT);
        }
        ClientLog.log(event.getType());
    }

    private void cancelCloseTimer() {
        getClose().cancel();
    }

    private void startCloseTimer(int delayMillis) {
        getClose().schedule(delayMillis);
    }

    public Timer getClose() {
        return timers.get(root);
    }

    public void setClose(Timer close) {
        timers.put(root, close);
    }
}