| /* 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.Paging | |
| * Strategy for vector feature paging | |
| * | |
| * Inherits from: | |
| * - <OpenLayers.Strategy> | |
| */ | |
| OpenLayers.Strategy.Paging = OpenLayers.Class(OpenLayers.Strategy, { | |
| /** | |
| * Property: features | |
| * {Array(<OpenLayers.Feature.Vector>)} Cached features. | |
| */ | |
| features: null, | |
| /** | |
| * Property: length | |
| * {Integer} Number of features per page. Default is 10. | |
| */ | |
| length: 10, | |
| /** | |
| * Property: num | |
| * {Integer} The currently displayed page number. | |
| */ | |
| num: null, | |
| /** | |
| * Property: paging | |
| * {Boolean} The strategy is currently changing pages. | |
| */ | |
| paging: false, | |
| /** | |
| * Constructor: OpenLayers.Strategy.Paging | |
| * Create a new paging 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} The strategy was successfully activated. | |
| */ | |
| activate: function() { | |
| var activated = OpenLayers.Strategy.prototype.activate.call(this); | |
| if(activated) { | |
| this.layer.events.on({ | |
| "beforefeaturesadded": this.cacheFeatures, | |
| scope: this | |
| }); | |
| } | |
| return activated; | |
| }, | |
| /** | |
| * APIMethod: deactivate | |
| * Deactivate the strategy. Unregister any listeners, do appropriate | |
| * tear-down. | |
| * | |
| * Returns: | |
| * {Boolean} The strategy was successfully deactivated. | |
| */ | |
| deactivate: function() { | |
| var deactivated = OpenLayers.Strategy.prototype.deactivate.call(this); | |
| if(deactivated) { | |
| this.clearCache(); | |
| this.layer.events.un({ | |
| "beforefeaturesadded": this.cacheFeatures, | |
| scope: this | |
| }); | |
| } | |
| return deactivated; | |
| }, | |
| /** | |
| * Method: cacheFeatures | |
| * Cache features before they are added to the layer. | |
| * | |
| * Parameters: | |
| * event - {Object} The event that this was listening for. This will come | |
| * with a batch of features to be paged. | |
| */ | |
| cacheFeatures: function(event) { | |
| if(!this.paging) { | |
| this.clearCache(); | |
| this.features = event.features; | |
| this.pageNext(event); | |
| } | |
| }, | |
| /** | |
| * Method: clearCache | |
| * Clear out the cached features. This destroys features, assuming | |
| * nothing else has a reference. | |
| */ | |
| clearCache: function() { | |
| if(this.features) { | |
| for(var i=0; i<this.features.length; ++i) { | |
| this.features[i].destroy(); | |
| } | |
| } | |
| this.features = null; | |
| this.num = null; | |
| }, | |
| /** | |
| * APIMethod: pageCount | |
| * Get the total count of pages given the current cache of features. | |
| * | |
| * Returns: | |
| * {Integer} The page count. | |
| */ | |
| pageCount: function() { | |
| var numFeatures = this.features ? this.features.length : 0; | |
| return Math.ceil(numFeatures / this.length); | |
| }, | |
| /** | |
| * APIMethod: pageNum | |
| * Get the zero based page number. | |
| * | |
| * Returns: | |
| * {Integer} The current page number being displayed. | |
| */ | |
| pageNum: function() { | |
| return this.num; | |
| }, | |
| /** | |
| * APIMethod: pageLength | |
| * Gets or sets page length. | |
| * | |
| * Parameters: | |
| * newLength: {Integer} Optional length to be set. | |
| * | |
| * Returns: | |
| * {Integer} The length of a page (number of features per page). | |
| */ | |
| pageLength: function(newLength) { | |
| if(newLength && newLength > 0) { | |
| this.length = newLength; | |
| } | |
| return this.length; | |
| }, | |
| /** | |
| * APIMethod: pageNext | |
| * Display the next page of features. | |
| * | |
| * Returns: | |
| * {Boolean} A new page was displayed. | |
| */ | |
| pageNext: function(event) { | |
| var changed = false; | |
| if(this.features) { | |
| if(this.num === null) { | |
| this.num = -1; | |
| } | |
| var start = (this.num + 1) * this.length; | |
| changed = this.page(start, event); | |
| } | |
| return changed; | |
| }, | |
| /** | |
| * APIMethod: pagePrevious | |
| * Display the previous page of features. | |
| * | |
| * Returns: | |
| * {Boolean} A new page was displayed. | |
| */ | |
| pagePrevious: function() { | |
| var changed = false; | |
| if(this.features) { | |
| if(this.num === null) { | |
| this.num = this.pageCount(); | |
| } | |
| var start = (this.num - 1) * this.length; | |
| changed = this.page(start); | |
| } | |
| return changed; | |
| }, | |
| /** | |
| * Method: page | |
| * Display the page starting at the given index from the cache. | |
| * | |
| * Returns: | |
| * {Boolean} A new page was displayed. | |
| */ | |
| page: function(start, event) { | |
| var changed = false; | |
| if(this.features) { | |
| if(start >= 0 && start < this.features.length) { | |
| var num = Math.floor(start / this.length); | |
| if(num != this.num) { | |
| this.paging = true; | |
| var features = this.features.slice(start, start + this.length); | |
| this.layer.removeFeatures(this.layer.features); | |
| this.num = num; | |
| // modify the event if any | |
| if(event && event.features) { | |
| // this.was called by an event listener | |
| event.features = features; | |
| } else { | |
| // this was called directly on the strategy | |
| this.layer.addFeatures(features); | |
| } | |
| this.paging = false; | |
| changed = true; | |
| } | |
| } | |
| } | |
| return changed; | |
| }, | |
| CLASS_NAME: "OpenLayers.Strategy.Paging" | |
| }); | |