- Author:
- David Nickerson <nickerso@users.sourceforge.net>
- Date:
- 2009-07-16 02:00:03+12:00
- Desc:
- the starting point for the HH tutorial example
- Permanent Source URI:
- https://models.fieldml.org/workspace/a1/rawfile/f6a8f90307388eb4b040ee3566b84d88b59247f7/dojo-presentation/js/dojo/dojox/data/KeyValueStore.js
dojo.provide("dojox.data.KeyValueStore");
dojo.require("dojo.data.util.filter");
dojo.require("dojo.data.util.simpleFetch");
dojo.declare("dojox.data.KeyValueStore", null, {
// summary:
// This is a dojo.data store implementation. It can take in either a Javascript
// array, JSON string, or URL as the data source. Data is expected to be in the
// following format:
// [
// { "key1": "value1" },
// { "key2": "value2" }
// ]
// This is to mimic the Java Properties file format. Each 'item' from this store
// is a JS object representing a key-value pair. If an item in the above array has
// more than one key/value pair, only the first will be used/accessed.
constructor: function(/* Object */ keywordParameters){
// summary: constructor
// keywordParameters: {url: String}
// keywordParameters: {data: string}
// keywordParameters: {dataVar: jsonObject}
if(keywordParameters.url){
this.url = keywordParameters.url;
}
this._keyValueString = keywordParameters.data;
this._keyValueVar = keywordParameters.dataVar;
this._keyAttribute = "key";
this._valueAttribute = "value";
this._storeProp = "_keyValueStore";
this._features = {
'dojo.data.api.Read': true,
'dojo.data.api.Identity': true
};
this._loadInProgress = false; //Got to track the initial load to prevent duelling loads of the dataset.
this._queuedFetches = [];
},
url: "",
data: "",
_assertIsItem: function(/* item */ item){
// summary:
// This function tests whether the item passed in is indeed an item in the store.
// item:
// The item to test for being contained by the store.
if(!this.isItem(item)){
throw new Error("dojox.data.KeyValueStore: a function was passed an item argument that was not an item");
}
},
_assertIsAttribute: function(/* item */ item, /* String */ attribute){
// summary:
// This function tests whether the item passed in is indeed a valid 'attribute' like type for the store.
// attribute:
// The attribute to test for being contained by the store.
if(!dojo.isString(attribute)){
throw new Error("dojox.data.KeyValueStore: a function was passed an attribute argument that was not an attribute object nor an attribute name string");
}
},
/***************************************
dojo.data.api.Read API
***************************************/
getValue: function( /* item */ item,
/* attribute-name-string */ attribute,
/* value? */ defaultValue){
// summary:
// See dojo.data.api.Read.getValue()
this._assertIsItem(item);
this._assertIsAttribute(item, attribute);
var value;
if(attribute == this._keyAttribute){ // Looking for key
value = item[this._keyAttribute];
}else{
value = item[this._valueAttribute]; // Otherwise, attribute == ('value' || the actual key )
}
if(value === undefined){
value = defaultValue;
}
return value;
},
getValues: function(/* item */ item,
/* attribute-name-string */ attribute){
// summary:
// See dojo.data.api.Read.getValues()
// Key/Value syntax does not support multi-valued attributes, so this is just a
// wrapper function for getValue().
var value = this.getValue(item, attribute);
return (value ? [value] : []); //Array
},
getAttributes: function(/* item */ item){
// summary:
// See dojo.data.api.Read.getAttributes()
return [this._keyAttribute, this._valueAttribute, item[this._keyAttribute]];
},
hasAttribute: function( /* item */ item,
/* attribute-name-string */ attribute){
// summary:
// See dojo.data.api.Read.hasAttribute()
this._assertIsItem(item);
this._assertIsAttribute(item, attribute);
return (attribute == this._keyAttribute || attribute == this._valueAttribute || attribute == item[this._keyAttribute]);
},
containsValue: function(/* item */ item,
/* attribute-name-string */ attribute,
/* anything */ value){
// summary:
// See dojo.data.api.Read.containsValue()
var regexp = undefined;
if(typeof value === "string"){
regexp = dojo.data.util.filter.patternToRegExp(value, false);
}
return this._containsValue(item, attribute, value, regexp); //boolean.
},
_containsValue: function( /* item */ item,
/* attribute || attribute-name-string */ attribute,
/* anything */ value,
/* RegExp?*/ regexp){
// summary:
// Internal function for looking at the values contained by the item.
// description:
// Internal function for looking at the values contained by the item. This
// function allows for denoting if the comparison should be case sensitive for
// strings or not (for handling filtering cases where string case should not matter)
//
// item:
// The data item to examine for attribute values.
// attribute:
// The attribute to inspect.
// value:
// The value to match.
// regexp:
// Optional regular expression generated off value if value was of string type to handle wildcarding.
// If present and attribute values are string, then it can be used for comparison instead of 'value'
var values = this.getValues(item, attribute);
for(var i = 0; i < values.length; ++i){
var possibleValue = values[i];
if(typeof possibleValue === "string" && regexp){
return (possibleValue.match(regexp) !== null);
}else{
//Non-string matching.
if(value === possibleValue){
return true; // Boolean
}
}
}
return false; // Boolean
},
isItem: function(/* anything */ something){
// summary:
// See dojo.data.api.Read.isItem()
if (something && something[this._storeProp] === this) {
return true; //Boolean
}
return false; //Boolean
},
isItemLoaded: function(/* anything */ something) {
// summary:
// See dojo.data.api.Read.isItemLoaded()
// The KeyValueStore always loads all items, so if it's an item, then it's loaded.
return this.isItem(something); //Boolean
},
loadItem: function(/* object */ keywordArgs){
// summary:
// See dojo.data.api.Read.loadItem()
// description:
// The KeyValueStore always loads all items, so if it's an item, then it's loaded.
// From the dojo.data.api.Read.loadItem docs:
// If a call to isItemLoaded() returns true before loadItem() is even called,
// then loadItem() need not do any work at all and will not even invoke
// the callback handlers.
},
getFeatures: function(){
// summary:
// See dojo.data.api.Read.getFeatures()
return this._features; //Object
},
close: function(/*dojo.data.api.Request || keywordArgs || null */ request){
// summary:
// See dojo.data.api.Read.close()
},
getLabel: function(/* item */ item){
// summary:
// See dojo.data.api.Read.getLabel()
return item[this._keyAttribute];
},
getLabelAttributes: function(/* item */ item){
// summary:
// See dojo.data.api.Read.getLabelAttributes()
return [this._keyAttribute];
},
// The dojo.data.api.Read.fetch() function is implemented as
// a mixin from dojo.data.util.simpleFetch.
// That mixin requires us to define _fetchItems().
_fetchItems: function( /* Object */ keywordArgs,
/* Function */ findCallback,
/* Function */ errorCallback){
// summary:
// See dojo.data.util.simpleFetch.fetch()
var self = this;
var filter = function(requestArgs, arrayOfAllItems){
var items = null;
if(requestArgs.query){
items = [];
var ignoreCase = requestArgs.queryOptions ? requestArgs.queryOptions.ignoreCase : false;
//See if there are any string values that can be regexp parsed first to avoid multiple regexp gens on the
//same value for each item examined. Much more efficient.
var regexpList = {};
for(var key in requestArgs.query){
var value = requestArgs.query[key];
if(typeof value === "string"){
regexpList[key] = dojo.data.util.filter.patternToRegExp(value, ignoreCase);
}
}
for(var i = 0; i < arrayOfAllItems.length; ++i){
var match = true;
var candidateItem = arrayOfAllItems[i];
for(var key in requestArgs.query){
var value = requestArgs.query[key];
if(!self._containsValue(candidateItem, key, value, regexpList[key])){
match = false;
}
}
if(match){
items.push(candidateItem);
}
}
}else if(requestArgs.identity){
items = [];
var item;
for(var key in arrayOfAllItems){
item = arrayOfAllItems[key];
if(item[self._keyAttribute] == requestArgs.identity){
items.push(item);
break;
}
}
}else{
// We want a copy to pass back in case the parent wishes to sort the array. We shouldn't allow resort
// of the internal list so that multiple callers can get lists and sort without affecting each other.
if(arrayOfAllItems.length> 0){
items = arrayOfAllItems.slice(0,arrayOfAllItems.length);
}
}
findCallback(items, requestArgs);
};
if(this._loadFinished){
filter(keywordArgs, this._arrayOfAllItems);
}else{
if(this.url !== ""){
//If fetches come in before the loading has finished, but while
//a load is in progress, we have to defer the fetching to be
//invoked in the callback.
if(this._loadInProgress){
this._queuedFetches.push({args: keywordArgs, filter: filter});
}else{
this._loadInProgress = true;
var getArgs = {
url: self.url,
handleAs: "json-comment-filtered"
};
var getHandler = dojo.xhrGet(getArgs);
getHandler.addCallback(function(data){
self._processData(data);
filter(keywordArgs, self._arrayOfAllItems);
self._handleQueuedFetches();
});
getHandler.addErrback(function(error){
self._loadInProgress = false;
throw error;
});
}
}else if(this._keyValueString){
this._processData(eval(this._keyValueString));
this._keyValueString = null;
filter(keywordArgs, this._arrayOfAllItems);
}else if(this._keyValueVar){
this._processData(this._keyValueVar);
this._keyValueVar = null;
filter(keywordArgs, this._arrayOfAllItems);
}else{
throw new Error("dojox.data.KeyValueStore: No source data was provided as either URL, String, or Javascript variable data input.");
}
}
},
_handleQueuedFetches: function(){
// summary:
// Internal function to execute delayed request in the store.
//Execute any deferred fetches now.
if(this._queuedFetches.length > 0){
for(var i = 0; i < this._queuedFetches.length; i++){
var fData = this._queuedFetches[i];
var delayedFilter = fData.filter;
var delayedQuery = fData.args;
if(delayedFilter){
delayedFilter(delayedQuery, this._arrayOfAllItems);
}else{
this.fetchItemByIdentity(fData.args);
}
}
this._queuedFetches = [];
}
},
_processData: function(/* Array */ data){
this._arrayOfAllItems = [];
for(var i=0; i<data.length; i++){
this._arrayOfAllItems.push(this._createItem(data[i]));
}
this._loadFinished = true;
this._loadInProgress = false;
},
_createItem: function(/* Object */ something){
var item = {};
item[this._storeProp] = this;
for(var i in something){
item[this._keyAttribute] = i;
item[this._valueAttribute] = something[i];
break;
}
return item; //Object
},
/***************************************
dojo.data.api.Identity API
***************************************/
getIdentity: function(/* item */ item){
// summary:
// See dojo.data.api.Identity.getIdentity()
if(this.isItem(item)){
return item[this._keyAttribute]; //String
}
return null; //null
},
getIdentityAttributes: function(/* item */ item){
// summary:
// See dojo.data.api.Identity.getIdentifierAttributes()
return [this._keyAttribute];
},
fetchItemByIdentity: function(/* object */ keywordArgs){
// summary:
// See dojo.data.api.Identity.fetchItemByIdentity()
keywordArgs.oldOnItem = keywordArgs.onItem;
keywordArgs.onItem = null;
keywordArgs.onComplete = this._finishFetchItemByIdentity ;
this.fetch(keywordArgs);
},
_finishFetchItemByIdentity: function(/* Array */ items, /* object */ request) {
var scope = request.scope || dojo.global;
if(items.length){
request.oldOnItem.call(scope, items[0]);
}else{
request.oldOnItem.call(scope, null);
}
}
});
//Mix in the simple fetch implementation to this class.
dojo.extend(dojox.data.KeyValueStore,dojo.data.util.simpleFetch);
