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Side by Side Diff: pkg/observe/lib/src/observable_map.dart

Issue 817483003: delete observe from the repo (Closed) Base URL: https://dart.googlecode.com/svn/branches/bleeding_edge/dart
Patch Set: Created 6 years ago
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1 // Copyright (c) 2013, the Dart project authors. Please see the AUTHORS file
2 // for details. All rights reserved. Use of this source code is governed by a
3 // BSD-style license that can be found in the LICENSE file.
4
5 library observe.src.observable_map;
6
7 import 'dart:collection';
8 import 'package:observe/observe.dart';
9
10
11 // TODO(jmesserly): this needs to be faster. We currently require multiple
12 // lookups per key to get the old value.
13 // TODO(jmesserly): this doesn't implement the precise interfaces like
14 // LinkedHashMap, SplayTreeMap or HashMap. However it can use them for the
15 // backing store.
16
17 // TODO(jmesserly): should we summarize map changes like we do for list changes?
18 class MapChangeRecord<K, V> extends ChangeRecord {
19 // TODO(jmesserly): we could store this more compactly if it matters, with
20 // subtypes for inserted and removed.
21
22 /// The map key that changed.
23 final K key;
24
25 /// The previous value associated with this key.
26 final V oldValue;
27
28 /// The new value associated with this key.
29 final V newValue;
30
31 /// True if this key was inserted.
32 final bool isInsert;
33
34 /// True if this key was removed.
35 final bool isRemove;
36
37 MapChangeRecord(this.key, this.oldValue, this.newValue)
38 : isInsert = false, isRemove = false;
39
40 MapChangeRecord.insert(this.key, this.newValue)
41 : isInsert = true, isRemove = false, oldValue = null;
42
43 MapChangeRecord.remove(this.key, this.oldValue)
44 : isInsert = false, isRemove = true, newValue = null;
45
46 String toString() {
47 var kind = isInsert ? 'insert' : isRemove ? 'remove' : 'set';
48 return '#<MapChangeRecord $kind $key from: $oldValue to: $newValue>';
49 }
50 }
51
52 /// Represents an observable map of model values. If any items are added,
53 /// removed, or replaced, then observers that are listening to [changes]
54 /// will be notified.
55 class ObservableMap<K, V> extends ChangeNotifier implements Map<K, V> {
56 final Map<K, V> _map;
57
58 /// Creates an observable map.
59 ObservableMap() : _map = new HashMap<K, V>();
60
61 /// Creates a new observable map using a [LinkedHashMap].
62 ObservableMap.linked() : _map = new LinkedHashMap<K, V>();
63
64 /// Creates a new observable map using a [SplayTreeMap].
65 ObservableMap.sorted() : _map = new SplayTreeMap<K, V>();
66
67 /// Creates an observable map that contains all key value pairs of [other].
68 /// It will attempt to use the same backing map type if the other map is a
69 /// [LinkedHashMap], [SplayTreeMap], or [HashMap]. Otherwise it defaults to
70 /// [HashMap].
71 ///
72 /// Note this will perform a shallow conversion. If you want a deep conversion
73 /// you should use [toObservable].
74 factory ObservableMap.from(Map<K, V> other) {
75 return new ObservableMap<K, V>.createFromType(other)..addAll(other);
76 }
77
78 /// Like [ObservableMap.from], but creates an empty map.
79 factory ObservableMap.createFromType(Map<K, V> other) {
80 ObservableMap result;
81 if (other is SplayTreeMap) {
82 result = new ObservableMap<K, V>.sorted();
83 } else if (other is LinkedHashMap) {
84 result = new ObservableMap<K, V>.linked();
85 } else {
86 result = new ObservableMap<K, V>();
87 }
88 return result;
89 }
90
91 @reflectable Iterable<K> get keys => _map.keys;
92
93 @reflectable Iterable<V> get values => _map.values;
94
95 @reflectable int get length =>_map.length;
96
97 @reflectable bool get isEmpty => length == 0;
98
99 @reflectable bool get isNotEmpty => !isEmpty;
100
101 @reflectable bool containsValue(Object value) => _map.containsValue(value);
102
103 @reflectable bool containsKey(Object key) => _map.containsKey(key);
104
105 @reflectable V operator [](Object key) => _map[key];
106
107 @reflectable void operator []=(K key, V value) {
108 if (!hasObservers) {
109 _map[key] = value;
110 return;
111 }
112
113 int len = _map.length;
114 V oldValue = _map[key];
115
116 _map[key] = value;
117
118 if (len != _map.length) {
119 notifyPropertyChange(#length, len, _map.length);
120 notifyChange(new MapChangeRecord.insert(key, value));
121 _notifyKeysValuesChanged();
122 } else if (oldValue != value) {
123 notifyChange(new MapChangeRecord(key, oldValue, value));
124 _notifyValuesChanged();
125 }
126 }
127
128 void addAll(Map<K, V> other) {
129 other.forEach((K key, V value) { this[key] = value; });
130 }
131
132 V putIfAbsent(K key, V ifAbsent()) {
133 int len = _map.length;
134 V result = _map.putIfAbsent(key, ifAbsent);
135 if (hasObservers && len != _map.length) {
136 notifyPropertyChange(#length, len, _map.length);
137 notifyChange(new MapChangeRecord.insert(key, result));
138 _notifyKeysValuesChanged();
139 }
140 return result;
141 }
142
143 V remove(Object key) {
144 int len = _map.length;
145 V result = _map.remove(key);
146 if (hasObservers && len != _map.length) {
147 notifyChange(new MapChangeRecord.remove(key, result));
148 notifyPropertyChange(#length, len, _map.length);
149 _notifyKeysValuesChanged();
150 }
151 return result;
152 }
153
154 void clear() {
155 int len = _map.length;
156 if (hasObservers && len > 0) {
157 _map.forEach((key, value) {
158 notifyChange(new MapChangeRecord.remove(key, value));
159 });
160 notifyPropertyChange(#length, len, 0);
161 _notifyKeysValuesChanged();
162 }
163 _map.clear();
164 }
165
166 void forEach(void f(K key, V value)) => _map.forEach(f);
167
168 String toString() => Maps.mapToString(this);
169
170 // Note: we don't really have a reasonable old/new value to use here.
171 // But this should fix "keys" and "values" in templates with minimal overhead.
172 void _notifyKeysValuesChanged() {
173 notifyChange(new PropertyChangeRecord(this, #keys, null, null));
174 _notifyValuesChanged();
175 }
176
177 void _notifyValuesChanged() {
178 notifyChange(new PropertyChangeRecord(this, #values, null, null));
179 }
180 }
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