/* Copyright (c) 2006-2010 by OpenLayers Contributors (see authors.txt for
* full list of contributors). Published under the Clear BSD license.
* See http://svn.openlayers.org/trunk/openlayers/license.txt for the
* full text of the license. */
/**
* @requires OpenLayers/Tile.js
* @requires OpenLayers/Request/XMLHttpRequest.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,
/**
* Property: request
* {<OpenLayers.Request.XMLHttpRequest>}
*/
request: 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;
if(this.request) {
this.request.abort();
//this.request.destroy();
this.request = null;
}
},
/**
* Method: clear
* Clear the tile of any bounds/position-related data so that it can
* be reused in a new location.
*/
clear: function() {
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
* Abort any pending requests and issue another request for data.
*
* Input are function pointers for what to do on success and failure.
*
* Parameters:
* success - {function}
* failure - {function}
*/
loadFeaturesForRegion:function(success, failure) {
if(this.request) {
this.request.abort();
}
this.request = OpenLayers.Request.GET({
url: this.url,
success: success,
failure: failure,
scope: this
});
},
/**
* Method: requestSuccess
* Called on return from request succcess. Adds results via
* layer.addFeatures in vector mode, addResults otherwise.
*
* Parameters:
* request - {<OpenLayers.Request.XMLHttpRequest>}
*/
requestSuccess:function(request) {
if (this.features) {
var doc = request.responseXML;
if (!doc || !doc.documentElement) {
doc = request.responseText;
}
if (this.layer.vectorMode) {
this.layer.addFeatures(this.layer.formatObject.read(doc));
} else {
var xml = new OpenLayers.Format.XML();
if (typeof doc == "string") {
doc = xml.read(doc);
}
var resultFeatures = xml.getElementsByTagNameNS(
doc, "http://www.opengis.net/gml", "featureMember"
);
this.addResults(resultFeatures);
}
}
if (this.events) {
this.events.triggerEvent("loadend");
}
//request produced with success, we can delete the request object.
//this.request.destroy();
this.request = null;
},
/**
* 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"
}
);