/**
* Copyright (C) 2011 Brian Ferris <bdferris@onebusaway.org>
*
* 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 org.onebusaway.webapp.gwt.common;
import com.google.gwt.maps.client.MapWidget;
import com.google.gwt.maps.client.event.MapZoomEndHandler;
import com.google.gwt.maps.client.geom.LatLng;
import com.google.gwt.maps.client.geom.LatLngBounds;
import com.google.gwt.maps.client.overlay.Overlay;
import java.util.HashMap;
import java.util.LinkedHashSet;
import java.util.Map;
import java.util.Set;
public class MapOverlayManager {
private Map<Overlay, ZoomCheck> _zoomByOverlay = new HashMap<Overlay, ZoomCheck>();
private Map<ZoomCheck, Set<Overlay>> _overlaysByZoom = new HashMap<ZoomCheck, Set<Overlay>>();
private MapWidget _map;
public MapOverlayManager() {
}
public MapOverlayManager(MapWidget map) {
_map = map;
_map.addMapZoomEndHandler(new MapZoomHandler());
}
public void setMapWidget(MapWidget map) {
_map = map;
map.addMapZoomEndHandler(new MapZoomHandler());
}
public MapWidget getMapWidget() {
return _map;
}
public void addOverlay(Overlay overlay) {
addOverlay(overlay, 0, 20);
}
public void addOverlay(Overlay overlay, int minZoom, int maxZoom) {
addOverlay(overlay, new ZoomRange(minZoom, maxZoom));
}
public void setCenter(LatLng center) {
_map.setCenter(center);
}
public void setCenterAndZoom(LatLng center, int zoomLevel) {
_map.setCenter(center, zoomLevel);
}
public void setCenterAndZoom(LatLngBounds bounds) {
_map.setCenter(bounds.getCenter(), _map.getBoundsZoomLevel(bounds));
}
/*****************************************************************************
* Private Methods
****************************************************************************/
private void addOverlay(Overlay overlay, ZoomCheck check) {
ZoomCheck current = _zoomByOverlay.get(overlay);
if (current != null) {
if (current.equals(check))
return;
removeOverlay(overlay);
}
_zoomByOverlay.put(overlay, check);
Set<Overlay> overlays = _overlaysByZoom.get(check);
if (overlays == null) {
overlays = new LinkedHashSet<Overlay>();
_overlaysByZoom.put(check, overlays);
}
overlays.add(overlay);
if (check.isVisible(_map.getZoomLevel()))
_map.addOverlay(overlay);
}
public void removeOverlay(Overlay overlay) {
ZoomCheck zoom = _zoomByOverlay.remove(overlay);
if (zoom != null) {
Set<Overlay> overlays = _overlaysByZoom.get(zoom);
if (overlays != null) {
overlays.remove(overlay);
}
if (zoom.isVisible(_map.getZoomLevel()))
_map.removeOverlay(overlay);
}
}
public void clear() {
for (Map.Entry<ZoomCheck, Set<Overlay>> entry : _overlaysByZoom.entrySet()) {
ZoomCheck check = entry.getKey();
if (check.isVisible(_map.getZoomLevel())) {
for (Overlay overlay : entry.getValue())
_map.removeOverlay(overlay);
}
}
_overlaysByZoom.clear();
}
private class MapZoomHandler implements MapZoomEndHandler {
public void onZoomEnd(MapZoomEndEvent event) {
for (Map.Entry<ZoomCheck, Set<Overlay>> entry : _overlaysByZoom.entrySet()) {
ZoomCheck check = entry.getKey();
boolean then = check.isVisible(event.getOldZoomLevel());
boolean now = check.isVisible(event.getNewZoomLevel());
if (!then && now) {
for (Overlay overlay : entry.getValue())
_map.addOverlay(overlay);
}
if (then && !now) {
for (Overlay overlay : entry.getValue())
_map.removeOverlay(overlay);
}
}
}
}
private interface ZoomCheck {
public boolean isVisible(int zoomLevel);
}
private class ZoomRange implements ZoomCheck {
private int _from;
private int _to;
public ZoomRange(int from, int to) {
_from = Math.min(from, to);
_to = Math.max(from, to);
}
public boolean isVisible(int zoomLevel) {
return _from <= zoomLevel && zoomLevel < _to;
}
@Override
public boolean equals(Object obj) {
if (obj == null || !(obj instanceof ZoomRange))
return false;
ZoomRange r = (ZoomRange) obj;
return _from == r._from && _to == r._to;
}
@Override
public int hashCode() {
return _from * 3 + _to * 7;
}
}
}