com.google.gwt.maps.client.overlay.StreetviewOverlay.java Source code

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Here is the source code for com.google.gwt.maps.client.overlay.StreetviewOverlay.java

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/*
 * Copyright 2009 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.core.client.JavaScriptObject;
import com.google.gwt.maps.client.event.StreetviewOverlayChangedHandler;
import com.google.gwt.maps.client.event.StreetviewOverlayChangedHandler.StreetviewOverlayChangedEvent;
import com.google.gwt.maps.client.impl.HandlerCollection;
import com.google.gwt.maps.client.impl.MapEvent;
import com.google.gwt.maps.client.impl.StreetviewOverlayImpl;
import com.google.gwt.maps.client.impl.EventImpl.BooleanCallback;
import com.google.gwt.maps.client.overlay.Overlay.ConcreteOverlay;

/**
 * A Street View overlay object displays where Street View is available by
 * highlighting roads in blue.
 * 
 * To add a Street View overlay to the map:
 * 
 * <pre>
 * StreetviewOverlay svOverlay = new StreetviewOverlay();
 * map.addOverlay(svOverlay);
 * </pre>
 */
public final class StreetviewOverlay extends ConcreteOverlay {

    public static StreetviewOverlay createPeer(JavaScriptObject jso) {
        StreetviewOverlay overlay = new StreetviewOverlay(jso);
        // perform bind to make sure the right JSO was passed
        StreetviewOverlayImpl.impl.bind(jso, overlay);
        return overlay;
    }

    private HandlerCollection<StreetviewOverlayChangedHandler> streetviewOverlayChangedHandlers;

    /**
     * Creates a new Street View overlay.
     * 
     * Use {@link com.google.gwt.maps.client.MapWidget#addOverlay(Overlay)} to add
     * this overlay to the map.
     */
    public StreetviewOverlay() {
        super(StreetviewOverlayImpl.impl.construct());
    }

    /**
     * Create this overlay from an existing JavaScriptObject instance.
     * 
     * @param jsoPeer an existing JavaScriptObject instance.
     */
    protected StreetviewOverlay(JavaScriptObject jsoPeer) {
        super(jsoPeer);
    }

    /**
     * This event is fired when the state of Street View data changes within the
     * current viewport. It is fired when moving the map from an area with Street
     * View data to one without, and vice-versa. It is also fired when the
     * addition of a {@link StreetviewOverlay} to the map results in Street View
     * data appearing within the current viewport.
     * 
     * @param handler the handler to call when this event fires.
     */
    public void addStreetviewOverlayChangedHandler(final StreetviewOverlayChangedHandler handler) {
        maybeInitStreetviewOverlayChangedHandlers();

        streetviewOverlayChangedHandlers.addHandler(handler, new BooleanCallback() {
            @Override
            public void callback(boolean hasStreetviewData) {
                StreetviewOverlayChangedEvent e = new StreetviewOverlayChangedEvent(StreetviewOverlay.this,
                        hasStreetviewData);
                handler.onChanged(e);
            }
        });
    }

    /**
     * Removes a single handler of this map previously added with
     * {@link StreetviewOverlay#addStreetviewOverlayChangedHandler(StreetviewOverlayChangedHandler)}
     * .
     * 
     * @param handler the handler to remove
     */
    public void removeStreetviewOverlayHandler(StreetviewOverlayChangedHandler handler) {
        if (streetviewOverlayChangedHandlers != null) {
            streetviewOverlayChangedHandlers.removeHandler(handler);
        }
    }

    /**
     * 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(StreetviewOverlayChangedEvent event) {
        maybeInitStreetviewOverlayChangedHandlers();
        streetviewOverlayChangedHandlers.trigger(event.hasStreetviewData());
    }

    private void maybeInitStreetviewOverlayChangedHandlers() {
        if (streetviewOverlayChangedHandlers == null) {
            streetviewOverlayChangedHandlers = new HandlerCollection<StreetviewOverlayChangedHandler>(jsoPeer,
                    MapEvent.CHANGED);
        }
    }
}