001    package org.openstreetmap.gui.jmapviewer.tilesources;
002    
003    //License: GPL.
004    
005    import java.awt.Image;
006    import java.io.IOException;
007    import java.net.MalformedURLException;
008    import java.net.URL;
009    import java.util.ArrayList;
010    import java.util.List;
011    import java.util.Locale;
012    import java.util.concurrent.Callable;
013    import java.util.concurrent.ExecutionException;
014    import java.util.concurrent.Executors;
015    import java.util.concurrent.Future;
016    import java.util.concurrent.TimeUnit;
017    import java.util.concurrent.TimeoutException;
018    import java.util.regex.Pattern;
019    
020    import javax.imageio.ImageIO;
021    import javax.xml.parsers.DocumentBuilder;
022    import javax.xml.parsers.DocumentBuilderFactory;
023    import javax.xml.parsers.ParserConfigurationException;
024    import javax.xml.xpath.XPath;
025    import javax.xml.xpath.XPathConstants;
026    import javax.xml.xpath.XPathExpression;
027    import javax.xml.xpath.XPathExpressionException;
028    import javax.xml.xpath.XPathFactory;
029    
030    import org.openstreetmap.gui.jmapviewer.Coordinate;
031    import org.w3c.dom.Document;
032    import org.w3c.dom.Node;
033    import org.w3c.dom.NodeList;
034    import org.xml.sax.InputSource;
035    import org.xml.sax.SAXException;
036    
037    public class BingAerialTileSource extends AbstractTMSTileSource {
038    
039        private static String API_KEY = "Arzdiw4nlOJzRwOz__qailc8NiR31Tt51dN2D7cm57NrnceZnCpgOkmJhNpGoppU";
040        private static volatile Future<List<Attribution>> attributions; // volatile is required for getAttribution(), see below.
041        private static String imageUrlTemplate;
042        private static Integer imageryZoomMax;
043        private static String[] subdomains;
044    
045        private static final Pattern subdomainPattern = Pattern.compile("\\{subdomain\\}");
046        private static final Pattern quadkeyPattern = Pattern.compile("\\{quadkey\\}");
047        private static final Pattern culturePattern = Pattern.compile("\\{culture\\}");
048    
049        public BingAerialTileSource() {
050            super("Bing Aerial Maps", "http://example.com/");
051        }
052    
053        protected class Attribution {
054            String attribution;
055            int minZoom;
056            int maxZoom;
057            Coordinate min;
058            Coordinate max;
059        }
060    
061        @Override
062        public String getTileUrl(int zoom, int tilex, int tiley) throws IOException {
063            // make sure that attribution is loaded. otherwise subdomains is null.
064            if (getAttribution() == null)
065                throw new IOException("Attribution is not loaded yet");
066    
067            int t = (zoom + tilex + tiley) % subdomains.length;
068            String subdomain = subdomains[t];
069    
070            String url = imageUrlTemplate;
071            url = subdomainPattern.matcher(url).replaceAll(subdomain);
072            url = quadkeyPattern.matcher(url).replaceAll(computeQuadTree(zoom, tilex, tiley));
073    
074            return url;
075        }
076    
077        protected URL getAttributionUrl() throws MalformedURLException {
078            return new URL("http://dev.virtualearth.net/REST/v1/Imagery/Metadata/Aerial?include=ImageryProviders&output=xml&key="
079                    + API_KEY);
080        }
081    
082        protected List<Attribution> parseAttributionText(InputSource xml) throws IOException {
083            try {
084                DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
085                DocumentBuilder builder = factory.newDocumentBuilder();
086                Document document = builder.parse(xml);
087    
088                XPathFactory xPathFactory = XPathFactory.newInstance();
089                XPath xpath = xPathFactory.newXPath();
090                imageUrlTemplate = xpath.compile("//ImageryMetadata/ImageUrl/text()").evaluate(document);
091                imageUrlTemplate = culturePattern.matcher(imageUrlTemplate).replaceAll(Locale.getDefault().toString());
092                imageryZoomMax = Integer.parseInt(xpath.compile("//ImageryMetadata/ZoomMax/text()").evaluate(document));
093    
094                NodeList subdomainTxt = (NodeList) xpath.compile("//ImageryMetadata/ImageUrlSubdomains/string/text()").evaluate(document, XPathConstants.NODESET);
095                subdomains = new String[subdomainTxt.getLength()];
096                for(int i = 0; i < subdomainTxt.getLength(); i++) {
097                    subdomains[i] = subdomainTxt.item(i).getNodeValue();
098                }
099    
100                XPathExpression attributionXpath = xpath.compile("Attribution/text()");
101                XPathExpression coverageAreaXpath = xpath.compile("CoverageArea");
102                XPathExpression zoomMinXpath = xpath.compile("ZoomMin/text()");
103                XPathExpression zoomMaxXpath = xpath.compile("ZoomMax/text()");
104                XPathExpression southLatXpath = xpath.compile("BoundingBox/SouthLatitude/text()");
105                XPathExpression westLonXpath = xpath.compile("BoundingBox/WestLongitude/text()");
106                XPathExpression northLatXpath = xpath.compile("BoundingBox/NorthLatitude/text()");
107                XPathExpression eastLonXpath = xpath.compile("BoundingBox/EastLongitude/text()");
108    
109                NodeList imageryProviderNodes = (NodeList) xpath.compile("//ImageryMetadata/ImageryProvider").evaluate(document, XPathConstants.NODESET);
110                List<Attribution> attributions = new ArrayList<Attribution>(imageryProviderNodes.getLength());
111                for (int i = 0; i < imageryProviderNodes.getLength(); i++) {
112                    Node providerNode = imageryProviderNodes.item(i);
113    
114                    String attribution = attributionXpath.evaluate(providerNode);
115    
116                    NodeList coverageAreaNodes = (NodeList) coverageAreaXpath.evaluate(providerNode, XPathConstants.NODESET);
117                    for(int j = 0; j < coverageAreaNodes.getLength(); j++) {
118                        Node areaNode = coverageAreaNodes.item(j);
119                        Attribution attr = new Attribution();
120                        attr.attribution = attribution;
121    
122                        attr.maxZoom = Integer.parseInt(zoomMaxXpath.evaluate(areaNode));
123                        attr.minZoom = Integer.parseInt(zoomMinXpath.evaluate(areaNode));
124    
125                        Double southLat = Double.parseDouble(southLatXpath.evaluate(areaNode));
126                        Double northLat = Double.parseDouble(northLatXpath.evaluate(areaNode));
127                        Double westLon = Double.parseDouble(westLonXpath.evaluate(areaNode));
128                        Double eastLon = Double.parseDouble(eastLonXpath.evaluate(areaNode));
129                        attr.min = new Coordinate(southLat, westLon);
130                        attr.max = new Coordinate(northLat, eastLon);
131    
132                        attributions.add(attr);
133                    }
134                }
135    
136                return attributions;
137            } catch (SAXException e) {
138                System.err.println("Could not parse Bing aerials attribution metadata.");
139                e.printStackTrace();
140            } catch (ParserConfigurationException e) {
141                e.printStackTrace();
142            } catch (XPathExpressionException e) {
143                e.printStackTrace();
144            }
145            return null;
146        }
147    
148        @Override
149        public int getMaxZoom() {
150            if(imageryZoomMax != null)
151                return imageryZoomMax;
152            else
153                return 22;
154        }
155    
156        @Override
157        public TileUpdate getTileUpdate() {
158            return TileUpdate.IfNoneMatch;
159        }
160    
161        @Override
162        public boolean requiresAttribution() {
163            return true;
164        }
165    
166        @Override
167        public String getAttributionLinkURL() {
168            //return "http://bing.com/maps"
169            // FIXME: I've set attributionLinkURL temporarily to ToU URL to comply with bing ToU
170            // (the requirement is that we have such a link at the bottom of the window)
171            return "http://go.microsoft.com/?linkid=9710837";
172        }
173    
174        @Override
175        public Image getAttributionImage() {
176            try {
177                return ImageIO.read(getClass().getResourceAsStream("/org/openstreetmap/gui/jmapviewer/images/bing_maps.png"));
178            } catch (IOException e) {
179                return null;
180            }
181        }
182    
183        @Override
184        public String getAttributionImageURL() {
185            return "http://opengeodata.org/microsoft-imagery-details";
186        }
187    
188        @Override
189        public String getTermsOfUseText() {
190            return null;
191        }
192    
193        @Override
194        public String getTermsOfUseURL() {
195            return "http://opengeodata.org/microsoft-imagery-details";
196        }
197    
198        protected Callable<List<Attribution>> getAttributionLoaderCallable() {
199            return new Callable<List<Attribution>>() {
200    
201                @Override
202                public List<Attribution> call() throws Exception {
203                    int waitTimeSec = 1;
204                    while (true) {
205                        try {
206                            InputSource xml = new InputSource(getAttributionUrl().openStream());
207                            List<Attribution> r = parseAttributionText(xml);
208                            System.out.println("Successfully loaded Bing attribution data.");
209                            return r;
210                        } catch (IOException ex) {
211                            System.err.println("Could not connect to Bing API. Will retry in " + waitTimeSec + " seconds.");
212                            Thread.sleep(waitTimeSec * 1000L);
213                            waitTimeSec *= 2;
214                        }
215                    }
216                }
217            };
218        }
219    
220        protected List<Attribution> getAttribution() {
221            if (attributions == null) {
222                // see http://www.cs.umd.edu/~pugh/java/memoryModel/DoubleCheckedLocking.html
223                synchronized (BingAerialTileSource.class) {
224                    if (attributions == null) {
225                        attributions = Executors.newSingleThreadExecutor().submit(getAttributionLoaderCallable());
226                    }
227                }
228            }
229            try {
230                return attributions.get(1000, TimeUnit.MILLISECONDS);
231            } catch (TimeoutException ex) {
232                System.err.println("Bing: attribution data is not yet loaded.");
233            } catch (ExecutionException ex) {
234                throw new RuntimeException(ex.getCause());
235            } catch (InterruptedException ign) {
236            }
237            return null;
238        }
239    
240        @Override
241        public String getAttributionText(int zoom, Coordinate topLeft, Coordinate botRight) {
242            try {
243                final List<Attribution> data = getAttribution();
244                if (data == null)
245                    return "Error loading Bing attribution data";
246                StringBuilder a = new StringBuilder();
247                for (Attribution attr : data) {
248                    if (zoom <= attr.maxZoom && zoom >= attr.minZoom) {
249                        if (topLeft.getLon() < attr.max.getLon() && botRight.getLon() > attr.min.getLon()
250                                && topLeft.getLat() > attr.min.getLat() && botRight.getLat() < attr.max.getLat()) {
251                            a.append(attr.attribution);
252                            a.append(" ");
253                        }
254                    }
255                }
256                return a.toString();
257            } catch (Exception e) {
258                e.printStackTrace();
259            }
260            return "Error loading Bing attribution data";
261        }
262    
263        static String computeQuadTree(int zoom, int tilex, int tiley) {
264            StringBuilder k = new StringBuilder();
265            for (int i = zoom; i > 0; i--) {
266                char digit = 48;
267                int mask = 1 << (i - 1);
268                if ((tilex & mask) != 0) {
269                    digit += 1;
270                }
271                if ((tiley & mask) != 0) {
272                    digit += 2;
273                }
274                k.append(digit);
275            }
276            return k.toString();
277        }
278    }