openlayers/lib/OpenLayers/Layer/GeoRSS.js

   1 /* Copyright (c) 2006-2008 MetaCarta, Inc., published under the Clear BSD
   2  * license.  See http://svn.openlayers.org/trunk/openlayers/license.txt for the
   3  * full text of the license. */
   4
   5
   6 /**
   7  * @requires OpenLayers/Layer/Markers.js
   8  * @requires OpenLayers/Request/XMLHttpRequest.js
   9  */
  10
  11 /**
  12  * Class: OpenLayers.Layer.GeoRSS
  13  * Add GeoRSS Point features to your map.
  14  *
  15  * Inherits from:
  16  *  - <OpenLayers.Layer.Markers>
  17  *  - <OpenLayers.Layer>
  18  */
  19 OpenLayers.Layer.GeoRSS = OpenLayers.Class(OpenLayers.Layer.Markers, {
  20
  21     /**
  22      * Property: location
  23      * {String} store url of text file
  24      */
  25     location: null,
  26
  27     /**
  28      * Property: features
  29      * {Array(<OpenLayers.Feature>)}
  30      */
  31     features: null,
  32
  33     /**
  34      * APIProperty: formatOptions
  35      * {Object} Hash of options which should be passed to the format when it is
  36      * created. Must be passed in the constructor.
  37      */
  38     formatOptions: null,
  39
  40     /**
  41      * Property: selectedFeature
  42      * {<OpenLayers.Feature>}
  43      */
  44     selectedFeature: null,
  45
  46     /**
  47      * APIProperty: icon
  48      * {<OpenLayers.Icon>}. This determines the Icon to be used on the map
  49      * for this GeoRSS layer.
  50      */
  51     icon: null,
  52
  53     /**
  54      * APIProperty: popupSize
  55      * {<OpenLayers.Size>} This determines the size of GeoRSS popups. If
  56      * not provided, defaults to 250px by 120px.
  57      */
  58     popupSize: null,
  59
  60     /**
  61      * APIProperty: useFeedTitle
  62      * {Boolean} Set layer.name to the first <title> element in the feed. Default is true.
  63      */
  64     useFeedTitle: true,
  65
  66     /**
  67     * Constructor: OpenLayers.Layer.GeoRSS
  68     * Create a GeoRSS Layer.
  69     *
  70     * Parameters:
  71     * name - {String}
  72     * location - {String}
  73     * options - {Object}
  74     */
  75     initialize: function(name, location, options) {
  76         OpenLayers.Layer.Markers.prototype.initialize.apply(this, [name, options]);
  77         this.location = location;
  78         this.features = [];
  79     },
  80
  81     /**
  82      * Method: destroy
  83      */
  84     destroy: function() {
  85         // Warning: Layer.Markers.destroy() must be called prior to calling
  86         // clearFeatures() here, otherwise we leak memory. Indeed, if
  87         // Layer.Markers.destroy() is called after clearFeatures(), it won't be
  88         // able to remove the marker image elements from the layer's div since
  89         // the markers will have been destroyed by clearFeatures().
  90         OpenLayers.Layer.Markers.prototype.destroy.apply(this, arguments);
  91         this.clearFeatures();
  92         this.features = null;
  93     },
  94
  95     /**
  96      * Method: loadRSS
  97      * Start the load of the RSS data. Don't do this when we first add the layer,
  98      * since we may not be visible at any point, and it would therefore be a waste.
  99      */
 100     loadRSS: function() {
 101         if (!this.loaded) {
 102             this.events.triggerEvent("loadstart");
 103             OpenLayers.Request.GET({
 104                 url: this.location,
 105                 success: this.parseData,
 106                 scope: this
 107             });
 108             this.loaded = true;
 109         }
 110     },
 111
 112     /**
 113      * Method: moveTo
 114      * If layer is visible and RSS has not been loaded, load RSS.
 115      *
 116      * Parameters:
 117      * bounds - {Object}
 118      * zoomChanged - {Object}
 119      * minor - {Object}
 120      */
 121     moveTo:function(bounds, zoomChanged, minor) {
 122         OpenLayers.Layer.Markers.prototype.moveTo.apply(this, arguments);
 123         if(this.visibility && !this.loaded){
 124             this.loadRSS();
 125         }
 126     },
 127
 128     /**
 129      * Method: parseData
 130      * Parse the data returned from the Events call.
 131      *
 132      * Parameters:
 133      * ajaxRequest - {<OpenLayers.Request.XMLHttpRequest>}
 134      */
 135     parseData: function(ajaxRequest) {
 136         var doc = ajaxRequest.responseXML;
 137         if (!doc || !doc.documentElement) {
 138             doc = OpenLayers.Format.XML.prototype.read(ajaxRequest.responseText);
 139         }
 140
 141         if (this.useFeedTitle) {
 142             var name = null;
 143             try {
 144                 name = doc.getElementsByTagNameNS('*', 'title')[0].firstChild.nodeValue;
 145             }
 146             catch (e) {
 147                 name = doc.getElementsByTagName('title')[0].firstChild.nodeValue;
 148             }
 149             if (name) {
 150                 this.setName(name);
 151             }
 152         }
 153
 154         var options = {};
 155
 156         OpenLayers.Util.extend(options, this.formatOptions);
 157
 158         if (this.map && !this.projection.equals(this.map.getProjectionObject())) {
 159             options.externalProjection = this.projection;
 160             options.internalProjection = this.map.getProjectionObject();
 161         }
 162
 163         var format = new OpenLayers.Format.GeoRSS(options);
 164         var features = format.read(doc);
 165
 166         for (var i=0, len=features.length; i<len; i++) {
 167             var data = {};
 168             var feature = features[i];
 169
 170             // we don't support features with no geometry in the GeoRSS
 171             // layer at this time.
 172             if (!feature.geometry) {
 173                 continue;
 174             }
 175
 176             var title = feature.attributes.title ?
 177                          feature.attributes.title : "Untitled";
 178
 179             var description = feature.attributes.description ?
 180                          feature.attributes.description : "No description.";
 181
 182             var link = feature.attributes.link ? feature.attributes.link : "";
 183
 184             var location = feature.geometry.getBounds().getCenterLonLat();
 185
 186
 187             data.icon = this.icon == null ?
 188                                      OpenLayers.Marker.defaultIcon() :
 189                                      this.icon.clone();
 190
 191             data.popupSize = this.popupSize ?
 192                              this.popupSize.clone() :
 193                              new OpenLayers.Size(250, 120);
 194
 195             if (title || description) {
 196                 // we have supplemental data, store them.
 197                 data.title = title;
 198                 data.description = description;
 199
 200                 var contentHTML = '<div class="olLayerGeoRSSClose">[x]</div>';
 201                 contentHTML += '<div class="olLayerGeoRSSTitle">';
 202                 if (link) {
 203                     contentHTML += '<a class="link" href="'+link+'" target="_blank">';
 204                 }
 205                 contentHTML += title;
 206                 if (link) {
 207                     contentHTML += '</a>';
 208                 }
 209                 contentHTML += '</div>';
 210                 contentHTML += '<div style="" class="olLayerGeoRSSDescription">';
 211                 contentHTML += description;
 212                 contentHTML += '</div>';
 213                 data['popupContentHTML'] = contentHTML;
 214             }
 215             var feature = new OpenLayers.Feature(this, location, data);
 216             this.features.push(feature);
 217             var marker = feature.createMarker();
 218             marker.events.register('click', feature, this.markerClick);
 219             this.addMarker(marker);
 220         }
 221         this.events.triggerEvent("loadend");
 222     },
 223
 224     /**
 225      * Method: markerClick
 226      *
 227      * Parameters:
 228      * evt - {Event}
 229      */
 230     markerClick: function(evt) {
 231         var sameMarkerClicked = (this == this.layer.selectedFeature);
 232         this.layer.selectedFeature = (!sameMarkerClicked) ? this : null;
 233         for(var i=0, len=this.layer.map.popups.length; i<len; i++) {
 234             this.layer.map.removePopup(this.layer.map.popups[i]);
 235         }
 236         if (!sameMarkerClicked) {
 237             var popup = this.createPopup();
 238             OpenLayers.Event.observe(popup.div, "click",
 239                 OpenLayers.Function.bind(function() {
 240                     for(var i=0, len=this.layer.map.popups.length; i<len; i++) {
 241                         this.layer.map.removePopup(this.layer.map.popups[i]);
 242                     }
 243                 }, this)
 244             );
 245             this.layer.map.addPopup(popup);
 246         }
 247         OpenLayers.Event.stop(evt);
 248     },
 249
 250     /**
 251      * Method: clearFeatures
 252      * Destroy all features in this layer.
 253      */
 254     clearFeatures: function() {
 255         if (this.features != null) {
 256             while(this.features.length > 0) {
 257                 var feature = this.features[0];
 258                 OpenLayers.Util.removeItem(this.features, feature);
 259                 feature.destroy();
 260             }
 261         }
 262     },
 263
 264     CLASS_NAME: "OpenLayers.Layer.GeoRSS"
 265 });