/*
* Copyright 2008 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package com.google.gwt.maps.client.overlay;
import com.google.gwt.maps.client.event.TrafficOverlayChangedHandler;
import com.google.gwt.maps.client.event.TrafficOverlayChangedHandler.TrafficOverlayChangedEvent;
import com.google.gwt.maps.client.impl.HandlerCollection;
import com.google.gwt.maps.client.impl.MapEvent;
import com.google.gwt.maps.client.impl.TrafficOverlayImpl;
import com.google.gwt.maps.client.impl.EventImpl.BooleanCallback;
import com.google.gwt.maps.client.overlay.Overlay.ConcreteOverlay;
/**
* A traffic overlay object displays road traffic information. The traffic
* overlay will only display traffic information for supported cities.
*
* To add a traffic overlay to the map:
*
* <pre>
* TrafficOverlay traffic = new TrafficOverlay();
* map.addOverlay(traffic);
* </pre>
*/
public final class TrafficOverlay extends ConcreteOverlay {
private HandlerCollection<TrafficOverlayChangedHandler> trafficOverlayChangedHandlers;
/**
* Creates a new traffic overlay.
*
* Use {@link com.google.gwt.maps.client.MapWidget#addOverlay(Overlay)} to add
* this overlay to the map.
*/
public TrafficOverlay() {
super(TrafficOverlayImpl.impl.construct());
}
/**
*
* This event is fired when the state of traffic data changes within the current viewport. This event may be fired either when moving the map between areas with and without traffic data or when the addition of a {@link TrafficOverlay} to the map results in traffic data appearing within the current viewport.
*
* @param handler the handler to call when this event fires.
*/
public void addTrafficOverlayChangedHandler(
final TrafficOverlayChangedHandler handler) {
maybeInitTrafficOverlayChangedHandlers();
trafficOverlayChangedHandlers.addHandler(handler,
new BooleanCallback() {
@Override
public void callback(boolean trafficInView) {
TrafficOverlayChangedEvent e = new TrafficOverlayChangedEvent(
TrafficOverlay.this, trafficInView);
handler.onChanged(e);
}
});
}
/**
* Removes a single handler of this map previously added with
* {@link TrafficOverlay#addTrafficOverlayChangedHandler(TrafficOverlayChangedHandler)}.
*
* @param handler the handler to remove
*/
public void removeTrafficOverlayHandler(TrafficOverlayChangedHandler handler) {
if (trafficOverlayChangedHandlers != null) {
trafficOverlayChangedHandlers.removeHandler(handler);
}
}
/**
* Shows or hides this overlay.
*
* @param visible <code>true</code> to show the overlay, false to hide.
*/
public void setVisible(boolean visible) {
TrafficOverlayImpl.impl.setVisible(this, visible);
}
/**
* Manually trigger the specified event on this object.
*
* Note: The trigger() methods are provided for unit testing purposes only.
*
* @param event an event to deliver to the handler.
*/
void trigger(TrafficOverlayChangedEvent event) {
maybeInitTrafficOverlayChangedHandlers();
trafficOverlayChangedHandlers.trigger(event.isTrafficInView());
}
private void maybeInitTrafficOverlayChangedHandlers() {
if (trafficOverlayChangedHandlers == null) {
trafficOverlayChangedHandlers = new HandlerCollection<TrafficOverlayChangedHandler>(
jsoPeer, MapEvent.CHANGED);
}
}
}