/* Copyright (c) 2006-2007 MetaCarta, Inc., published under the BSD license. * See http://svn.openlayers.org/trunk/openlayers/release-license.txt  * for the full text of the license. */ /** * @requires OpenLayers/Tile.js *  * Class: OpenLayers.Tile.WFS * Instances of OpenLayers.Tile.WFS are used to manage the image tiles * used by various layers.  Create a new image tile with the * <OpenLayers.Tile.WFS> constructor. * * Inherits from: *  - <OpenLayers.Tile> */OpenLayers.Tile.WFS = OpenLayers.Class(OpenLayers.Tile, {    /**      * Property: features      * {Array(<OpenLayers.Feature>)} list of features in this tile      */    features: null,    /**      * Property: url      * {String}      */    url: null,        /** TBD 3.0 - reorder the parameters to the init function to put URL      *             as last, so we can continue to call tile.initialize()      *             without changing the arguments.      *      * Constructor: OpenLayers.Tile.WFS     * Constructor for a new <OpenLayers.Tile.WFS> instance.     *      * Parameters:     * layer - {<OpenLayers.Layer>} layer that the tile will go in.     * position - {<OpenLayers.Pixel>}     * bounds - {<OpenLayers.Bounds>}     * url - {<String>}     * size - {<OpenLayers.Size>}     */       initialize: function(layer, position, bounds, url, size) {        OpenLayers.Tile.prototype.initialize.apply(this, arguments);        this.url = url;                this.features = [];    },    /**      * APIMethod: destroy     * nullify references to prevent circular references and memory leaks     */    destroy: function() {        OpenLayers.Tile.prototype.destroy.apply(this, arguments);        this.destroyAllFeatures();        this.features = null;        this.url = null;    },    /**      * Method: clear     *  Clear the tile of any bounds/position-related data so that it can      *   be reused in a new location.     */    clear: function() {        OpenLayers.Tile.prototype.clear.apply(this, arguments);        this.destroyAllFeatures();    },        /**     * Method: draw     * Check that a tile should be drawn, and load features for it.     */    draw:function() {        if (OpenLayers.Tile.prototype.draw.apply(this, arguments)) {            if (this.isLoading) {                //if already loading, send 'reload' instead of 'loadstart'.                this.events.triggerEvent("reload");             } else {                this.isLoading = true;                this.events.triggerEvent("loadstart");            }            this.loadFeaturesForRegion(this.requestSuccess);        }    },    /**     * Method: loadFeaturesForRegion    * get the full request string from the ds and the tile params     *     and call the AJAX loadURL().     *    * Input are function pointers for what to do on success and failure.    *    * Parameters:    * success - {function}    * failure - {function}    */    loadFeaturesForRegion:function(success, failure) {        OpenLayers.loadURL(this.url, null, this, success);    },        /**    * Method: requestSuccess    * Called on return from request succcess. Adds results via     * layer.addFeatures in vector mode, addResults otherwise.     *    * Parameters:    * request - {XMLHttpRequest}    */    requestSuccess:function(request) {        if (this.features) {            var doc = request.responseXML;                        if (!doc || request.fileType!="XML") {                doc = OpenLayers.parseXMLString(request.responseText);            }            if (this.layer.vectorMode) {                var gml = new OpenLayers.Format.GML({                    'extractAttributes': this.layer.options.extractAttributes                });                this.layer.addFeatures(gml.read(doc));            } else {                var resultFeatures = OpenLayers.Ajax.getElementsByTagNameNS(                    doc, "http://www.opengis.net/gml", "gml", "featureMember"                );                this.addResults(resultFeatures);            }        }        if (this.events) {            this.events.triggerEvent("loadend");         }    },    /**     * Method: addResults     * Construct new feature via layer featureClass constructor, and add to     * this.features.     *      * Parameters:     * results - {Object}     */    addResults: function(results) {        for (var i=0; i < results.length; i++) {            var feature = new this.layer.featureClass(this.layer,                                                       results[i]);            this.features.push(feature);        }    },    /**      * Method: destroyAllFeatures     * Iterate through and call destroy() on each feature, removing it from     *   the local array     */    destroyAllFeatures: function() {        while(this.features.length > 0) {            var feature = this.features.shift();            feature.destroy();        }    },    CLASS_NAME: "OpenLayers.Tile.WFS"  });