#915 Adding support for GeoJSON vector format. Many thanks to Chris for the exhaustive tests on this one.
git-svn-id: http://svn.openlayers.org/trunk/openlayers@3994 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf
This commit is contained in:
Tim Schaub
376
lib/OpenLayers/Format/JSON.js
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376
lib/OpenLayers/Format/JSON.js
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/* Copyright (c) 2006 MetaCarta, Inc., published under a modified BSD license.
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* See http://svn.openlayers.org/trunk/openlayers/repository-license.txt
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* for the full text of the license. */
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/**
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* Note:
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* This work draws heavily from the public domain JSON serializer/deserializer
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* at http://www.json.org/json.js. Rewritten so that it doesn't modify
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* basic data prototypes.
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*/
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/**
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* @requires OpenLayers/Format.js
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*
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* Class: OpenLayers.Format.JSON
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* A parser to read/write JSON safely. Create a new instance with the
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* <OpenLayers.Format.JSON> constructor.
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*
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* Inherits from:
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* - <OpenLayers.Format>
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*/
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OpenLayers.Format.JSON = OpenLayers.Class(OpenLayers.Format, {
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/**
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* APIProperty: indent
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* {String} For "pretty" printing, the indent string will be used once for
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* each indentation level.
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*/
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indent: " ",
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/**
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* APIProperty: space
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* {String} For "pretty" printing, the space string will be used after
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* the ":" separating a name/value pair.
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*/
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space: " ",
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/**
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* APIProperty: newline
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* {String} For "pretty" printing, the newline string will be used at the
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* end of each name/value pair or array item.
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*/
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newline: "\n",
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/**
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* Property: level
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* {Integer} For "pretty" printing, this is incremented/decremented during
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* serialization.
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*/
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level: 0,
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/**
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* Property: pretty
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* {Boolean} Serialize with extra whitespace for structure. This is set
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* by the <write> method.
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*/
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pretty: false,
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/**
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* Constructor: OpenLayers.Format.JSON
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* Create a new parser for JSON.
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*
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* Parameters:
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* options - {Object} An optional object whose properties will be set on
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* this instance.
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*/
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initialize: function(options) {
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OpenLayers.Format.prototype.initialize.apply(this, [options]);
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},
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/**
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* APIMethod: read
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* Deserialize a json string.
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*
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* Parameters:
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* json - {String} A JSON string
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* filter - {Function} A function which will be called for every key and
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* value at every level of the final result. Each value will be
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* replaced by the result of the filter function. This can be used to
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* reform generic objects into instances of classes, or to transform
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* date strings into Date objects.
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*
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* Returns:
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* {Object} An object, array, string, or number .
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*/
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read: function(json, filter) {
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/**
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* Parsing happens in three stages. In the first stage, we run the text
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* against a regular expression which looks for non-JSON
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* characters. We are especially concerned with '()' and 'new'
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* because they can cause invocation, and '=' because it can cause
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* mutation. But just to be safe, we will reject all unexpected
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* characters.
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*/
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try {
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if(/^("(\\.|[^"\\\n\r])*?"|[,:{}\[\]0-9.\-+Eaeflnr-u \n\r\t])+?$/.
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test(json)) {
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/**
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* In the second stage we use the eval function to compile the
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* text into a JavaScript structure. The '{' operator is
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* subject to a syntactic ambiguity in JavaScript - it can
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* begin a block or an object literal. We wrap the text in
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* parens to eliminate the ambiguity.
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*/
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var object = eval('(' + json + ')');
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/**
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* In the optional third stage, we recursively walk the new
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* structure, passing each name/value pair to a filter
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* function for possible transformation.
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*/
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if(typeof filter === 'function') {
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function walk(k, v) {
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if(v && typeof v === 'object') {
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for(var i in v) {
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if(v.hasOwnProperty(i)) {
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v[i] = walk(i, v[i]);
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}
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}
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}
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return filter(k, v);
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}
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object = walk('', object);
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}
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return object;
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}
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} catch(e) {
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// Fall through if the regexp test fails.
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}
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return null;
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},
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/**
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* APIMethod: write
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* Serialize an object into a JSON string.
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*
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* Parameters:
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* value - {String} The object, array, string, number, boolean or date
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* to be serialized.
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* pretty - {Boolean} Structure the output with newlines and indentation.
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* Default is false.
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*
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* Returns:
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* {String} The JSON string representation of the input value.
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*/
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write: function(value, pretty) {
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this.pretty = !!pretty;
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var json = null;
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var type = typeof value;
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if(this.serialize[type]) {
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json = this.serialize[type].apply(this, [value]);
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}
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return json;
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},
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/**
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* Method: writeIndent
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* Output an indentation string depending on the indentation level.
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*
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* Returns:
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* {String} An appropriate indentation string.
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*/
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writeIndent: function() {
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var pieces = [];
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if(this.pretty) {
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for(var i=0; i<this.level; ++i) {
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pieces.push(this.indent);
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}
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}
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return pieces.join('');
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},
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/**
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* Method: writeNewline
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* Output a string representing a newline if in pretty printing mode.
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*
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* Returns:
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* {String} A string representing a new line.
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*/
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writeNewline: function() {
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return (this.pretty) ? this.newline : '';
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},
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/**
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* Method: writeSpace
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* Output a string representing a space if in pretty printing mode.
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*
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* Returns:
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* {String} A space.
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*/
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writeSpace: function() {
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return (this.pretty) ? this.space : '';
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},
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/**
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* Property: serialize
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* Object with properties corresponding to the serializable data types.
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* Property values are functions that do the actual serializing.
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*/
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serialize: {
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/**
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* Method: serialize.object
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* Transform an object into a JSON string.
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*
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* Parameters:
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* object - {Object} The object to be serialized.
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*
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* Returns:
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* {String} A JSON string representing the object.
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*/
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'object': function(object) {
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// three special objects that we want to treat differently
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if(object == null) {
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return "null";
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}
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if(object.constructor == Date) {
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return this.serialize.date.apply(this, [object]);
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}
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if(object.constructor == Array) {
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return this.serialize.array.apply(this, [object]);
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}
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var pieces = ['{'];
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this.level += 1;
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var key, keyJSON, valueJSON;
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var addComma = false;
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for(key in object) {
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if(object.hasOwnProperty(key)) {
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// recursive calls need to allow for sub-classing
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keyJSON = OpenLayers.Format.JSON.prototype.write.apply(this,
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[key, this.pretty]);
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valueJSON = OpenLayers.Format.JSON.prototype.write.apply(this,
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[object[key], this.pretty]);
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if(keyJSON != null && valueJSON != null) {
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if(addComma) {
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pieces.push(',');
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}
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pieces.push(this.writeNewline(), this.writeIndent(),
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keyJSON, ':', this.writeSpace(), valueJSON);
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addComma = true;
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}
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}
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}
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this.level -= 1;
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pieces.push(this.writeNewline(), this.writeIndent(), '}');
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return pieces.join('');
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},
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/**
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* Method: serialize.array
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* Transform an array into a JSON string.
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*
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* Parameters:
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* array - {Array} The array to be serialized
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*
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* Returns:
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* {String} A JSON string representing the array.
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*/
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'array': function(array) {
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var json;
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var pieces = ['['];
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this.level += 1;
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for(var i=0; i<array.length; ++i) {
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// recursive calls need to allow for sub-classing
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json = OpenLayers.Format.JSON.prototype.write.apply(this,
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[array[i], this.pretty]);
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if(json != null) {
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if(i > 0) {
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pieces.push(',');
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}
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pieces.push(this.writeNewline(), this.writeIndent(), json);
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}
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}
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this.level -= 1;
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pieces.push(this.writeNewline(), this.writeIndent(), ']');
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return pieces.join('');
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},
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/**
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* Method: serialize.string
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* Transform a string into a JSON string.
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*
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* Parameters
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* string - {String} The string to be serialized
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*
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* Returns:
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* {String} A JSON string representing the string.
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*/
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'string': function(string) {
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// If the string contains no control characters, no quote characters, and no
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// backslash characters, then we can simply slap some quotes around it.
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// Otherwise we must also replace the offending characters with safe
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// sequences.
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var m = {
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'\b': '\\b',
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'\t': '\\t',
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'\n': '\\n',
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'\f': '\\f',
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'\r': '\\r',
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'"' : '\\"',
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'\\': '\\\\'
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};
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if(/["\\\x00-\x1f]/.test(string)) {
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return '"' + string.replace(/([\x00-\x1f\\"])/g, function(a, b) {
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var c = m[b];
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if(c) {
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return c;
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}
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c = b.charCodeAt();
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return '\\u00' +
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Math.floor(c / 16).toString(16) +
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(c % 16).toString(16);
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}) + '"';
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}
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return '"' + string + '"';
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},
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/**
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* Method: serialize.number
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* Transform a number into a JSON string.
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*
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* Parameters:
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* number - {Number} The number to be serialized.
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*
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* Returns:
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* {String} A JSON string representing the number.
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*/
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'number': function(number) {
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return isFinite(number) ? String(number) : "null";
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},
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/**
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* Method: serialize.boolean
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* Transform a boolean into a JSON string.
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*
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* Parameters:
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* bool - {Boolean} The boolean to be serialized.
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*
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* Returns:
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* {String} A JSON string representing the boolean.
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*/
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'boolean': function(bool) {
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return String(bool);
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},
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/**
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* Method: serialize.object
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* Transform a date into a JSON string.
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*
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* Parameters:
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* date - {Date} The date to be serialized.
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*
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* Returns:
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* {String} A JSON string representing the date.
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*/
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'date': function(date) {
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function format(number) {
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// Format integers to have at least two digits.
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return (number < 10) ? '0' + number : number;
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}
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return '"' + date.getFullYear() + '-' +
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format(date.getMonth() + 1) + '-' +
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format(date.getDate()) + 'T' +
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format(date.getHours()) + ':' +
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format(date.getMinutes()) + ':' +
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format(date.getSeconds()) + '"';
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}
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},
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CLASS_NAME: "OpenLayers.Format.JSON"
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});
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