256f027c7c
layers, and not load by default if the layer is not visible. Includes tests. Default Behavior can be changed with 'OpenLayers.Strategy.Fixed.prototype.preload=true;'. With review from elemoine, comments from tschaub, review from me. Patch by Edgemaster. (Closes #1852) git-svn-id: http://svn.openlayers.org/trunk/openlayers@8775 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf
97 lines
2.6 KiB
JavaScript
97 lines
2.6 KiB
JavaScript
/* Copyright (c) 2006-2008 MetaCarta, Inc., published under the Clear BSD
|
|
* license. See http://svn.openlayers.org/trunk/openlayers/license.txt for the
|
|
* full text of the license. */
|
|
|
|
/**
|
|
* @requires OpenLayers/Strategy.js
|
|
*/
|
|
|
|
/**
|
|
* Class: OpenLayers.Strategy.Fixed
|
|
* A simple strategy that requests features once and never requests new data.
|
|
*
|
|
* Inherits from:
|
|
* - <OpenLayers.Strategy>
|
|
*/
|
|
OpenLayers.Strategy.Fixed = OpenLayers.Class(OpenLayers.Strategy, {
|
|
|
|
/**
|
|
* APIProperty: preload
|
|
* {Boolean} Load data before layer made visible. Enabling this may result
|
|
* in considerable overhead if your application loads many data layers
|
|
* that are not visible by default. Default is true.
|
|
*/
|
|
preload: false,
|
|
|
|
/**
|
|
* Constructor: OpenLayers.Strategy.Fixed
|
|
* Create a new Fixed strategy.
|
|
*
|
|
* Parameters:
|
|
* options - {Object} Optional object whose properties will be set on the
|
|
* instance.
|
|
*/
|
|
initialize: function(options) {
|
|
OpenLayers.Strategy.prototype.initialize.apply(this, [options]);
|
|
},
|
|
|
|
/**
|
|
* APIMethod: destroy
|
|
* Clean up the strategy.
|
|
*/
|
|
destroy: function() {
|
|
OpenLayers.Strategy.prototype.destroy.apply(this, arguments);
|
|
},
|
|
|
|
/**
|
|
* Method: activate
|
|
* Activate the strategy: load data or add listener to load when visible
|
|
*
|
|
* Returns:
|
|
* {Boolean} True if the strategy was successfully activated or false if
|
|
* the strategy was already active.
|
|
*/
|
|
activate: function() {
|
|
if(OpenLayers.Strategy.prototype.activate.apply(this, arguments)) {
|
|
if(this.layer.visibility == true || this.preload) {
|
|
this.load();
|
|
} else {
|
|
this.layer.events.on({
|
|
"visibilitychanged": this.load,
|
|
scope: this
|
|
});
|
|
}
|
|
return true;
|
|
}
|
|
return false;
|
|
},
|
|
|
|
/**
|
|
* Method: load
|
|
* Tells protocol to load data and unhooks the visibilitychanged event
|
|
*/
|
|
load: function() {
|
|
this.layer.protocol.read({
|
|
callback: this.merge,
|
|
scope: this
|
|
});
|
|
this.layer.events.un({
|
|
"visibilitychanged": this.load,
|
|
scope: this
|
|
});
|
|
},
|
|
|
|
/**
|
|
* Method: merge
|
|
* Add all features to the layer.
|
|
*/
|
|
merge: function(resp) {
|
|
var features = resp.features;
|
|
if (features && features.length > 0) {
|
|
this.layer.addFeatures(features);
|
|
}
|
|
},
|
|
|
|
CLASS_NAME: "OpenLayers.Strategy.Fixed"
|
|
});
|