1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
|
/*
Copyright (c) 2004-2011, The Dojo Foundation All Rights Reserved.
Available via Academic Free License >= 2.1 OR the modified BSD license.
see: http://dojotoolkit.org/license for details
*/
if(!dojo._hasResource["dojo.store.Observable"]){ //_hasResource checks added by build. Do not use _hasResource directly in your code.
dojo._hasResource["dojo.store.Observable"] = true;
dojo.provide("dojo.store.Observable");
dojo.getObject("store", true, dojo);
dojo.store.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 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 = dojo.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){
dojo.when(results, function(resultsArray){
var atEnd = resultsArray.length != options.count;
var i;
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){
// 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)){
if(removedFrom > -1){
// put back in the original slot so it doesn't move unless it needs to (relying on a stable sort below)
resultsArray.splice(removedFrom, 0, changed);
}else{
resultsArray.push(changed);
}
insertedInto = dojo.indexOf(queryExecutor(resultsArray), changed);
if((options.start && insertedInto == 0) ||
(!atEnd && insertedInto == resultsArray.length -1)){
// if it is at the end of the page, assume it goes into the prev or next page
insertedInto = -1;
}
}
}else if(changed){
// 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
listeners.splice(dojo.indexOf(listeners, listener), 1);
if(!listeners.length){
// no more listeners, remove the query updater too
queryUpdaters.splice(dojo.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{
return dojo.when(original.apply(this, arguments), 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;
};
}
|
