160 lines
5.6 KiB
JavaScript
160 lines
5.6 KiB
JavaScript
goog.provide('ol.FeatureLoader');
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goog.provide('ol.FeatureUrlFunction');
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goog.provide('ol.featureloader');
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goog.require('goog.asserts');
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goog.require('ol.TileState');
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goog.require('ol.VectorTile');
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goog.require('ol.format.FormatType');
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goog.require('ol.proj');
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goog.require('ol.proj.Projection');
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goog.require('ol.xml');
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/**
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* {@link ol.source.Vector} sources use a function of this type to load
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* features.
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*
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* This function takes an {@link ol.Extent} representing the area to be loaded,
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* a `{number}` representing the resolution (map units per pixel) and an
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* {@link ol.proj.Projection} for the projection as arguments. `this` within
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* the function is bound to the {@link ol.source.Vector} it's called from.
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*
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* The function is responsible for loading the features and adding them to the
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* source.
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* @api
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* @typedef {function(this:ol.source.Vector, ol.Extent, number,
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* ol.proj.Projection)}
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*/
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ol.FeatureLoader;
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/**
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* {@link ol.source.Vector} sources use a function of this type to get the url
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* to load features from.
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*
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* This function takes an {@link ol.Extent} representing the area to be loaded,
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* a `{number}` representing the resolution (map units per pixel) and an
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* {@link ol.proj.Projection} for the projection as arguments and returns a
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* `{string}` representing the URL.
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* @api
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* @typedef {function(ol.Extent, number, ol.proj.Projection) : string}
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*/
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ol.FeatureUrlFunction;
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/**
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* @param {string|ol.FeatureUrlFunction} url Feature URL service.
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* @param {ol.format.Feature} format Feature format.
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* @param {function(this:ol.VectorTile, Array.<ol.Feature>, ol.proj.Projection)|function(this:ol.source.Vector, Array.<ol.Feature>)} success
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* Function called with the loaded features and optionally with the data
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* projection. Called with the vector tile or source as `this`.
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* @param {function(this:ol.VectorTile)|function(this:ol.source.Vector)} failure
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* Function called when loading failed. Called with the vector tile or
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* source as `this`.
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* @return {ol.FeatureLoader} The feature loader.
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*/
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ol.featureloader.loadFeaturesXhr = function(url, format, success, failure) {
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return (
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/**
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* @param {ol.Extent} extent Extent.
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* @param {number} resolution Resolution.
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* @param {ol.proj.Projection} projection Projection.
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* @this {ol.source.Vector|ol.VectorTile}
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*/
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function(extent, resolution, projection) {
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var xhr = new XMLHttpRequest();
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xhr.open('GET',
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goog.isFunction(url) ? url(extent, resolution, projection) : url,
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true);
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if (format.getType() == ol.format.FormatType.ARRAY_BUFFER) {
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xhr.responseType = 'arraybuffer';
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}
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/**
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* @param {Event} event Event.
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* @private
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*/
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xhr.onload = function(event) {
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if (xhr.status < 400) {
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var type = format.getType();
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/** @type {Document|Node|Object|string|undefined} */
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var source;
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if (type == ol.format.FormatType.JSON ||
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type == ol.format.FormatType.TEXT) {
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source = /** @type {string} */ (xhr.responseText);
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} else if (type == ol.format.FormatType.XML) {
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source = xhr.responseXML;
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if (!source) {
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source = ol.xml.parse(xhr.responseText);
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}
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} else if (type == ol.format.FormatType.ARRAY_BUFFER) {
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source = /** @type {ArrayBuffer} */ (xhr.response);
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} else {
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goog.asserts.fail('unexpected format type');
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}
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if (source) {
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success.call(this, format.readFeatures(source,
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{featureProjection: projection}),
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format.readProjection(source));
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} else {
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goog.asserts.fail('undefined or null source');
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}
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} else {
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failure.call(this);
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}
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}.bind(this);
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xhr.send();
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});
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};
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/**
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* Create an XHR feature loader for a `url` and `format`. The feature loader
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* loads features (with XHR), parses the features, and adds them to the
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* vector tile.
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* @param {string|ol.FeatureUrlFunction} url Feature URL service.
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* @param {ol.format.Feature} format Feature format.
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* @return {ol.FeatureLoader} The feature loader.
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* @api
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*/
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ol.featureloader.tile = function(url, format) {
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return ol.featureloader.loadFeaturesXhr(url, format,
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/**
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* @param {Array.<ol.Feature>} features The loaded features.
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* @param {ol.proj.Projection} dataProjection Data projection.
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* @this {ol.VectorTile}
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*/
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function(features, dataProjection) {
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this.setProjection(dataProjection);
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this.setFeatures(features);
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},
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/**
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* @this {ol.VectorTile}
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*/
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function() {
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this.setState(ol.TileState.ERROR);
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});
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};
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/**
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* Create an XHR feature loader for a `url` and `format`. The feature loader
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* loads features (with XHR), parses the features, and adds them to the
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* vector source.
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* @param {string|ol.FeatureUrlFunction} url Feature URL service.
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* @param {ol.format.Feature} format Feature format.
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* @return {ol.FeatureLoader} The feature loader.
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* @api
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*/
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ol.featureloader.xhr = function(url, format) {
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return ol.featureloader.loadFeaturesXhr(url, format,
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/**
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* @param {Array.<ol.Feature>} features The loaded features.
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* @param {ol.proj.Projection} dataProjection Data projection.
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* @this {ol.source.Vector}
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*/
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function(features, dataProjection) {
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this.addFeatures(features);
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}, /* FIXME handle error */ ol.nullFunction);
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};
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