116 lines
3.9 KiB
JavaScript
116 lines
3.9 KiB
JavaScript
/*
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Copyright (c) 2004-2011, The Dojo Foundation All Rights Reserved.
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Available via Academic Free License >= 2.1 OR the modified BSD license.
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see: http://dojotoolkit.org/license for details
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*/
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if(!dojo._hasResource["dojo.store.util.SimpleQueryEngine"]){ //_hasResource checks added by build. Do not use _hasResource directly in your code.
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dojo._hasResource["dojo.store.util.SimpleQueryEngine"] = true;
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dojo.provide("dojo.store.util.SimpleQueryEngine");
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dojo.getObject("store.util", true, dojo);
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dojo.store.util.SimpleQueryEngine = function(query, options){
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// summary:
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// Simple query engine that matches using filter functions, named filter
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// functions or objects by name-value on a query object hash
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//
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// description:
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// The SimpleQueryEngine provides a way of getting a QueryResults through
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// the use of a simple object hash as a filter. The hash will be used to
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// match properties on data objects with the corresponding value given. In
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// other words, only exact matches will be returned.
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//
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// This function can be used as a template for more complex query engines;
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// for example, an engine can be created that accepts an object hash that
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// contains filtering functions, or a string that gets evaluated, etc.
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//
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// When creating a new dojo.store, simply set the store's queryEngine
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// field as a reference to this function.
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//
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// query: Object
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// An object hash with fields that may match fields of items in the store.
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// Values in the hash will be compared by normal == operator, but regular expressions
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// or any object that provides a test() method are also supported and can be
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// used to match strings by more complex expressions
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// (and then the regex's or object's test() method will be used to match values).
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//
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// options: dojo.store.util.SimpleQueryEngine.__queryOptions?
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// An object that contains optional information such as sort, start, and count.
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//
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// returns: Function
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// A function that caches the passed query under the field "matches". See any
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// of the "query" methods on dojo.stores.
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//
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// example:
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// Define a store with a reference to this engine, and set up a query method.
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//
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// | var myStore = function(options){
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// | // ...more properties here
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// | this.queryEngine = dojo.store.util.SimpleQueryEngine;
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// | // define our query method
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// | this.query = function(query, options){
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// | return dojo.store.util.QueryResults(this.queryEngine(query, options)(this.data));
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// | };
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// | };
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// create our matching query function
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switch(typeof query){
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default:
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throw new Error("Can not query with a " + typeof query);
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case "object": case "undefined":
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var queryObject = query;
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query = function(object){
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for(var key in queryObject){
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var required = queryObject[key];
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if(required && required.test){
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if(!required.test(object[key])){
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return false;
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}
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}else if(required != object[key]){
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return false;
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}
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}
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return true;
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};
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break;
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case "string":
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// named query
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if(!this[query]){
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throw new Error("No filter function " + query + " was found in store");
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}
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query = this[query];
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// fall through
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case "function":
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// fall through
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}
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function execute(array){
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// execute the whole query, first we filter
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var results = dojo.filter(array, query);
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// next we sort
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if(options && options.sort){
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results.sort(function(a, b){
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for(var sort, i=0; sort = options.sort[i]; i++){
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var aValue = a[sort.attribute];
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var bValue = b[sort.attribute];
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if (aValue != bValue) {
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return !!sort.descending == aValue > bValue ? -1 : 1;
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}
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}
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return 0;
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});
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}
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// now we paginate
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if(options && (options.start || options.count)){
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var total = results.length;
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results = results.slice(options.start || 0, (options.start || 0) + (options.count || Infinity));
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results.total = total;
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}
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return results;
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}
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execute.matches = query;
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return execute;
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};
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}
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