/* 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/Strategy.js
*/
/**
* Class: OpenLayers.Strategy.Refresh
* A strategy that refreshes the layer. By default the strategy waits for a
* call to <refresh> before refreshing. By configuring the strategy with
* the <interval> option, refreshing can take place automatically.
*
* Inherits from:
* - <OpenLayers.Strategy>
*/
OpenLayers.Strategy.Refresh = OpenLayers.Class(OpenLayers.Strategy, {
/**
* Property: force
* {Boolean} Force a refresh on the layer. Default is false.
*/
force: false,
/**
* Property: interval
* {Number} Auto-refresh. Default is 0. If > 0, layer will be refreshed
* every N milliseconds.
*/
interval: 0,
/**
* Property: timer
* {Number} The id of the timer.
*/
timer: null,
/**
* Constructor: OpenLayers.Strategy.Refresh
* Create a new Refresh 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: activate
* Activate the strategy. Register any listeners, do appropriate setup.
*
* Returns:
* {Boolean} True if the strategy was successfully activated.
*/
activate: function() {
var activated = OpenLayers.Strategy.prototype.activate.call(this);
if(activated) {
if(this.layer.visibility === true) {
this.start();
}
this.layer.events.on({
"visibilitychanged": this.reset,
scope: this
});
}
return activated;
},
/**
* APIMethod: deactivate
* Deactivate the strategy. Unregister any listeners, do appropriate
* tear-down.
*
* Returns:
* {Boolean} True if the strategy was successfully deactivated.
*/
deactivate: function() {
var deactivated = OpenLayers.Strategy.prototype.deactivate.call(this);
if(deactivated) {
this.stop();
}
return deactivated;
},
/**
* Method: reset
* Start or cancel the refresh interval depending on the visibility of
* the layer.
*/
reset: function() {
if(this.layer.visibility === true) {
this.start();
} else {
this.stop();
}
},
/**
* Method: start
* Start the refresh interval.
*/
start: function() {
if(this.interval && typeof this.interval === "number" &&
this.interval > 0) {
this.timer = window.setInterval(
OpenLayers.Function.bind(this.refresh, this),
this.interval);
}
},
/**
* APIMethod: refresh
* Tell the strategy to refresh which will refresh the layer.
*/
refresh: function() {
if (this.layer && this.layer.refresh &&
typeof this.layer.refresh == "function") {
this.layer.refresh({force: this.force});
}
},
/**
* Method: stop
* Cancels the refresh interval.
*/
stop: function() {
if(this.timer !== null) {
window.clearInterval(this.timer);
this.timer = null;
}
},
CLASS_NAME: "OpenLayers.Strategy.Refresh"
});
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