+++ /dev/null
-define("dojo/store/Observable", ["../_base/kernel", "../_base/lang", "../_base/Deferred", "../_base/array"
-], function(kernel, lang, Deferred, array) {
- // module:
- // dojo/store/Observable
- // summary:
- // TODOC
-
-var ds = lang.getObject("dojo.store", true);
-
-return ds.Observable = function(store){
- // summary:
- // The Observable store wrapper takes a store and sets an observe method on query()
- // results that can be used to monitor results for changes.
- //
- // description:
- // Observable wraps an existing store so that notifications can be made when a query
- // is performed.
- //
- // example:
- // Create a Memory store that returns an observable query, and then log some
- // information about that query.
- //
- // | var store = dojo.store.Observable(new dojo.store.Memory({
- // | data: [
- // | {id: 1, name: "one", prime: false},
- // | {id: 2, name: "two", even: true, prime: true},
- // | {id: 3, name: "three", prime: true},
- // | {id: 4, name: "four", even: true, prime: false},
- // | {id: 5, name: "five", prime: true}
- // | ]
- // | }));
- // | var changes = [], results = store.query({ prime: true });
- // | var observer = results.observe(function(object, previousIndex, newIndex){
- // | changes.push({previousIndex:previousIndex, newIndex:newIndex, object:object});
- // | });
- //
- // See the Observable tests for more information.
-
- var undef, queryUpdaters = [], revision = 0;
- // a Comet driven store could directly call notify to notify observers when data has
- // changed on the backend
- store.notify = function(object, existingId){
- revision++;
- var updaters = queryUpdaters.slice();
- for(var i = 0, l = updaters.length; i < l; i++){
- updaters[i](object, existingId);
- }
- };
- var originalQuery = store.query;
- store.query = function(query, options){
- options = options || {};
- var results = originalQuery.apply(this, arguments);
- if(results && results.forEach){
- var nonPagedOptions = lang.mixin({}, options);
- delete nonPagedOptions.start;
- delete nonPagedOptions.count;
-
- var queryExecutor = store.queryEngine && store.queryEngine(query, nonPagedOptions);
- var queryRevision = revision;
- var listeners = [], queryUpdater;
- results.observe = function(listener, includeObjectUpdates){
- if(listeners.push(listener) == 1){
- // first listener was added, create the query checker and updater
- queryUpdaters.push(queryUpdater = function(changed, existingId){
- Deferred.when(results, function(resultsArray){
- var atEnd = resultsArray.length != options.count;
- var i, l, listener;
- if(++queryRevision != revision){
- throw new Error("Query is out of date, you must observe() the query prior to any data modifications");
- }
- var removedObject, removedFrom = -1, insertedInto = -1;
- if(existingId !== undef){
- // remove the old one
- for(i = 0, l = resultsArray.length; i < l; i++){
- var object = resultsArray[i];
- if(store.getIdentity(object) == existingId){
- removedObject = object;
- removedFrom = i;
- if(queryExecutor || !changed){// if it was changed and we don't have a queryExecutor, we shouldn't remove it because updated objects would be eliminated
- resultsArray.splice(i, 1);
- }
- break;
- }
- }
- }
- if(queryExecutor){
- // add the new one
- if(changed &&
- // if a matches function exists, use that (probably more efficient)
- (queryExecutor.matches ? queryExecutor.matches(changed) : queryExecutor([changed]).length)){
-
- var firstInsertedInto = removedFrom > -1 ?
- removedFrom : // put back in the original slot so it doesn't move unless it needs to (relying on a stable sort below)
- resultsArray.length;
- resultsArray.splice(firstInsertedInto, 0, changed); // add the new item
- insertedInto = array.indexOf(queryExecutor(resultsArray), changed); // sort it
- // we now need to push the chagne back into the original results array
- resultsArray.splice(firstInsertedInto, 1); // remove the inserted item from the previous index
-
- if((options.start && insertedInto == 0) ||
- (!atEnd && insertedInto == resultsArray.length)){
- // if it is at the end of the page, assume it goes into the prev or next page
- insertedInto = -1;
- }else{
- resultsArray.splice(insertedInto, 0, changed); // and insert into the results array with the correct index
- }
- }
- }else if(changed && !options.start){
- // we don't have a queryEngine, so we can't provide any information
- // about where it was inserted, but we can at least indicate a new object
- insertedInto = removedFrom >= 0 ? removedFrom : (store.defaultIndex || 0);
- }
- if((removedFrom > -1 || insertedInto > -1) &&
- (includeObjectUpdates || !queryExecutor || (removedFrom != insertedInto))){
- var copyListeners = listeners.slice();
- for(i = 0;listener = copyListeners[i]; i++){
- listener(changed || removedObject, removedFrom, insertedInto);
- }
- }
- });
- });
- }
- return {
- cancel: function(){
- // remove this listener
- var index = array.indexOf(listeners, listener);
- if(index > -1){ // check to make sure we haven't already called cancel
- listeners.splice(index, 1);
- if(!listeners.length){
- // no more listeners, remove the query updater too
- queryUpdaters.splice(array.indexOf(queryUpdaters, queryUpdater), 1);
- }
- }
- }
- };
- };
- }
- return results;
- };
- var inMethod;
- function whenFinished(method, action){
- var original = store[method];
- if(original){
- store[method] = function(value){
- if(inMethod){
- // if one method calls another (like add() calling put()) we don't want two events
- return original.apply(this, arguments);
- }
- inMethod = true;
- try{
- var results = original.apply(this, arguments);
- Deferred.when(results, function(results){
- action((typeof results == "object" && results) || value);
- });
- return results;
- }finally{
- inMethod = false;
- }
- };
- }
- }
- // monitor for updates by listening to these methods
- whenFinished("put", function(object){
- store.notify(object, store.getIdentity(object));
- });
- whenFinished("add", function(object){
- store.notify(object);
- });
- whenFinished("remove", function(id){
- store.notify(undefined, id);
- });
-
- return store;
-};
-});
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