39d002488c
git-svn-id: http://svn.openlayers.org/branches/openlayers/2.9@10264 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf
138 lines
3.9 KiB
JavaScript
138 lines
3.9 KiB
JavaScript
/* Copyright (c) 2006-2008 MetaCarta, Inc., published under the Clear BSD
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* license. See http://svn.openlayers.org/trunk/openlayers/license.txt for the
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* full text of the license. */
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/**
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* @requires OpenLayers/Strategy.js
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*/
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/**
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* Class: OpenLayers.Strategy.Fixed
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* A simple strategy that requests features once and never requests new data.
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*
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* Inherits from:
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* - <OpenLayers.Strategy>
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*/
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OpenLayers.Strategy.Fixed = OpenLayers.Class(OpenLayers.Strategy, {
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/**
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* APIProperty: preload
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* {Boolean} Load data before layer made visible. Enabling this may result
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* in considerable overhead if your application loads many data layers
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* that are not visible by default. Default is false.
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*/
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preload: false,
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/**
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* Constructor: OpenLayers.Strategy.Fixed
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* Create a new Fixed strategy.
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*
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* Parameters:
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* options - {Object} Optional object whose properties will be set on the
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* instance.
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*/
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initialize: function(options) {
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OpenLayers.Strategy.prototype.initialize.apply(this, [options]);
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},
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/**
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* APIMethod: destroy
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* Clean up the strategy.
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*/
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destroy: function() {
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OpenLayers.Strategy.prototype.destroy.apply(this, arguments);
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},
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/**
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* Method: activate
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* Activate the strategy: load data or add listener to load when visible
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*
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* Returns:
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* {Boolean} True if the strategy was successfully activated or false if
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* the strategy was already active.
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*/
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activate: function() {
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if(OpenLayers.Strategy.prototype.activate.apply(this, arguments)) {
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this.layer.events.on({
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"refresh": this.load,
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scope: this
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});
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if(this.layer.visibility == true || this.preload) {
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this.load();
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} else {
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this.layer.events.on({
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"visibilitychanged": this.load,
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scope: this
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});
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}
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return true;
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}
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return false;
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},
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/**
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* Method: deactivate
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* Deactivate the strategy. Undo what is done in <activate>.
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*
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* Returns:
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* {Boolean} The strategy was successfully deactivated.
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*/
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deactivate: function() {
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var deactivated = OpenLayers.Strategy.prototype.deactivate.call(this);
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if(deactivated) {
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this.layer.events.un({
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"refresh": this.load,
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"visibilitychanged": this.load,
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scope: this
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});
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}
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return deactivated;
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},
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/**
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* Method: load
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* Tells protocol to load data and unhooks the visibilitychanged event
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*
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* Parameters:
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* options - {Object} options to pass to protocol read.
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*/
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load: function(options) {
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this.layer.events.triggerEvent("loadstart");
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this.layer.protocol.read(OpenLayers.Util.applyDefaults({
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callback: this.merge,
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filter: this.layer.filter,
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scope: this
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}, options));
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this.layer.events.un({
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"visibilitychanged": this.load,
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scope: this
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});
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},
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/**
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* Method: merge
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* Add all features to the layer.
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*/
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merge: function(resp) {
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this.layer.destroyFeatures();
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var features = resp.features;
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if (features && features.length > 0) {
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var remote = this.layer.projection;
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var local = this.layer.map.getProjectionObject();
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if(!local.equals(remote)) {
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var geom;
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for(var i=0, len=features.length; i<len; ++i) {
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geom = features[i].geometry;
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if(geom) {
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geom.transform(remote, local);
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}
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}
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}
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this.layer.addFeatures(features);
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}
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this.layer.events.triggerEvent("loadend");
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},
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CLASS_NAME: "OpenLayers.Strategy.Fixed"
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});
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