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Copyright 2012 Yahoo! Inc. All rights reserved.
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Licensed under the BSD License.
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http://yuilibrary.com/license/
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YUI.add('dataschema-xml', function(Y) {
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Provides a DataSchema implementation which can be used to work with XML data.
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@submodule dataschema-xml
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Provides a DataSchema implementation which can be used to work with XML data.
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See the `apply` method for usage.
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@extends DataSchema.Base
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////////////////////////////////////////////////////////////////////////////
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// DataSchema.XML static methods
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////////////////////////////////////////////////////////////////////////////
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Applies a schema to an XML data tree, returning a normalized object with
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results in the `results` property. Additional information can be parsed out
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of the XML for inclusion in the `meta` property of the response object. If
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an error is encountered during processing, an `error` property will be
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Field data in the nodes captured by the XPath in _schema.resultListLocator_
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is extracted with the field identifiers described in _schema.resultFields_.
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Field identifiers are objects with the following properties:
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* `key` : <strong>(required)</strong> The desired property name to use
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store the retrieved value in the result object. If `locator` is
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not specified, `key` is also used as the XPath locator (String)
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* `locator`: The XPath locator to the node or attribute within each
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result node found by _schema.resultListLocator_ containing the
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desired field data (String)
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* `parser` : A function or the name of a function on `Y.Parsers` used
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to convert the input value into a normalized type. Parser
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functions are passed the value as input and are expected to
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* `schema` : Used to retrieve nested field data into an array for
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assignment as the result field value. This object follows the same
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conventions as _schema_.
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If no value parsing or nested parsing is needed, you can use XPath locators
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(strings) instead of field identifiers (objects) -- see example below.
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`response.results` will contain an array of objects with key:value pairs.
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The keys are the field identifier `key`s, and the values are the data
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values extracted from the nodes or attributes found by the field `locator`
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To extract additional information from the XML, include an array of
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XPath locators in _schema.metaFields_. The collected values will be
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stored in `response.meta` with the XPath locator as keys.
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resultListLocator: '//produce/item',
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parser: function (val) { return val.toUpperCase(); }
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// <item><name>Banana</name><color>yellow</color></item>
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// <item><name>Orange</name><color>orange</color></item>
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// <item><name>Eggplant</name><color>purple</color></item>
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var response = Y.DataSchema.JSON.apply(schema, data);
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// response.results[0] is { name: "Banana", color: "YELLOW" }
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@param {Object} schema Schema to apply. Supported configuration
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@param {String} [schema.resultListLocator] XPath locator for the
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XML nodes that contain the data to flatten into `response.results`
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@param {Array} [schema.resultFields] Field identifiers to
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locate/assign values in the response records. See above for
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@param {Array} [schema.metaFields] XPath locators to extract extra
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non-record related information from the XML data
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@param {XMLDoc} data XML data to parse
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@return {Object} An Object with properties `results` and `meta`
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apply: function(schema, data) {
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var xmldoc = data, // unnecessary variables
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data_out = { results: [], meta: {} };
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if (xmldoc && okNodeType[xmldoc.nodeType] && schema) {
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// Parse results data
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data_out = SchemaXML._parseResults(schema, xmldoc, data_out);
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data_out = SchemaXML._parseMeta(schema.metaFields, xmldoc, data_out);
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data_out.error = new Error("XML schema parse failure");
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* Get an XPath-specified value for a given field from an XML node or document.
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* @method _getLocationValue
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* @param field {String | Object} Field definition.
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* @param context {Object} XML node or document to search within.
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* @return {Object} Data value or null.
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_getLocationValue: function(field, context) {
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var locator = field.locator || field.key || field,
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xmldoc = context.ownerDocument || context,
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result, res, value = null;
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result = SchemaXML._getXPathResult(locator, context, xmldoc);
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while ((res = result.iterateNext())) {
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value = res.textContent || res.value || res.text || res.innerHTML || null;
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// FIXME: Why defer to a method that is mixed into this object?
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// DSchema.Base is mixed into DSchema.XML (et al), so
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// DSchema.XML.parse(...) will work. This supports the use case
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// where DSchema.Base.parse is changed, and that change is then
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// seen by all DSchema.* implementations, but does not support the
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// case where redefining DSchema.XML.parse changes behavior. In
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// fact, DSchema.XML.parse is never even called.
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return Y.DataSchema.Base.parse.call(this, value, field);
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* Fetches the XPath-specified result for a given location in an XML node
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* @method _getXPathResult
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* @param locator {String} The XPath location.
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* @param context {Object} XML node or document to search within.
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* @param xmldoc {Object} XML document to resolve namespace.
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* @return {Object} Data collection or null.
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_getXPathResult: function(locator, context, xmldoc) {
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if (! Lang.isUndefined(xmldoc.evaluate)) {
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return xmldoc.evaluate(locator, context, xmldoc.createNSResolver(context.ownerDocument ? context.ownerDocument.documentElement : context.documentElement), 0, null);
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var values=[], locatorArray = locator.split(/\b\/\b/), i=0, l=locatorArray.length, location, subloc, m, isNth;
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// XPath is supported
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// this fixes the IE 5.5+ issue where childnode selectors begin at 0 instead of 1
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xmldoc.setProperty("SelectionLanguage", "XPath");
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values = context.selectNodes(locator);
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// Fallback for DOM nodes and fragments
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// Iterate over each locator piece
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for (; i<l && context; i++) {
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location = locatorArray[i];
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if ((location.indexOf("[") > -1) && (location.indexOf("]") > -1)) {
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subloc = location.slice(location.indexOf("[")+1, location.indexOf("]"));
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//XPath is 1-based while DOM is 0-based
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context = context.children[subloc];
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// grab attribute value @
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else if (location.indexOf("@") > -1) {
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subloc = location.substr(location.indexOf("@"));
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context = subloc ? context.getAttribute(subloc.replace('@', '')) : context;
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// grab that last instance of tagName
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else if (-1 < location.indexOf("//")) {
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subloc = context.getElementsByTagName(location.substr(2));
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context = subloc.length ? subloc[subloc.length - 1] : null;
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// find the last matching location in children
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else if (l != i + 1) {
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for (m=context.childNodes.length-1; 0 <= m; m-=1) {
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if (location === context.childNodes[m].tagName) {
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context = context.childNodes[m];
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if (Lang.isString(context)) {
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values[0] = {value: context};
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values[0] = {value: context.innerHTML};
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values = Y.Array(context.childNodes, 0, true);
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// returning a mock-standard object for IE
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iterateNext: function() {
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if (this.index >= this.values.length) {return undefined;}
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var result = this.values[this.index];
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* Schema-parsed result field.
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* @method _parseField
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* @param field {String | Object} Required. Field definition.
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* @param result {Object} Required. Schema parsed data object.
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* @param context {Object} Required. XML node or document to search within.
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_parseField: function(field, result, context) {
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var key = field.key || field,
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parsed = { results: [], meta: {} };
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parsed = SchemaXML._parseResults(field.schema, context, parsed);
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result[key] = parsed.results;
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result[key] = SchemaXML._getLocationValue(field, context);
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* Parses results data according to schema
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* @param xmldoc_in {Object} XML document parse.
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* @param data_out {Object} In-progress schema-parsed data to update.
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* @return {Object} Schema-parsed data.
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_parseMeta: function(metaFields, xmldoc_in, data_out) {
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if(Lang.isObject(metaFields)) {
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xmldoc = xmldoc_in.ownerDocument || xmldoc_in;
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for(key in metaFields) {
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if (metaFields.hasOwnProperty(key)) {
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data_out.meta[key] = SchemaXML._getLocationValue(metaFields[key], xmldoc);
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* Schema-parsed result to add to results list.
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* @method _parseResult
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* @param fields {Array} Required. A collection of field definition.
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* @param context {Object} Required. XML node or document to search within.
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* @return {Object} Schema-parsed data.
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_parseResult: function(fields, context) {
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// Find each field value
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for (j=fields.length-1; 0 <= j; j--) {
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SchemaXML._parseField(fields[j], result, context);
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* Schema-parsed list of results from full data
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* @method _parseResults
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* @param schema {Object} Schema to parse against.
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* @param context {Object} XML node or document to parse.
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* @param data_out {Object} In-progress schema-parsed data to update.
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* @return {Object} Schema-parsed data.
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_parseResults: function(schema, context, data_out) {
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if (schema.resultListLocator && Lang.isArray(schema.resultFields)) {
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var xmldoc = context.ownerDocument || context,
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fields = schema.resultFields,
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if (schema.resultListLocator.match(/^[:\-\w]+$/)) {
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nodeList = context.getElementsByTagName(schema.resultListLocator);
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// loop through each result node
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for (i = nodeList.length - 1; i >= 0; --i) {
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results[i] = SchemaXML._parseResult(fields, nodeList[i]);
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nodeList = SchemaXML._getXPathResult(schema.resultListLocator, context, xmldoc);
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// loop through the nodelist
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while ((node = nodeList.iterateNext())) {
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results[i] = SchemaXML._parseResult(fields, node);
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if (results.length) {
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data_out.results = results;
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data_out.error = new Error("XML schema result nodes retrieval failure");
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Y.DataSchema.XML = Y.mix(SchemaXML, Y.DataSchema.Base);
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}, '3.5.1' ,{requires:['dataschema-base']});