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
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
|
/* __ *\
** ________ ___ / / ___ Scala API **
** / __/ __// _ | / / / _ | (c) 2003-2010, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ **
** /____/\___/_/ |_/____/_/ | | **
** |/ **
\* */
// $Id$
package scala.collection
package mutable
import generic._
import annotation.migration
/** A template trait for mutable maps of type `mutable.Map[A, B]` which
* associate keys of type `A` with values of type `B`.
*
* @tparam A the type of the keys.
* @tparam B the type of associated values.
* @tparam This the type of the `Map` itself.
*
* $mapnote
*
* @author Martin Odersky
* @version 2.8
* @since 2.8
* @define mapnote
* To implement a concrete mutable map, you need to provide implementations
* of the following methods:
* {{{
* def get(key: A): Option[B]
* def iterator: Iterator[(A, B)]
* def += (kv: (A, B)): this.type
* def -= (key: A): this.type
* }}}
* If you wish that methods like `take`,
* `drop`, `filter` return the same kind of map, you
* should also override:
* {{{
* def> empty: This
* }}}
* If you wish to avoid the unnecessary construction of an `Option`
* object, you could also override `apply`, `update`,
* and `delete`.
* It is also good idea to override methods `foreach` and
* `size` for efficiency.
* @define coll mutable map
* @define Coll mutable.Map
*/
trait MapLike[A, B, +This <: MapLike[A, B, This] with Map[A, B]]
extends scala.collection.MapLike[A, B, This]
with Builder[(A, B), This]
with Growable[(A, B)]
with Shrinkable[A]
with Cloneable[This]
{ self =>
import scala.collection.Traversable
/** A common implementation of `newBuilder` for all mutable maps
* in terms of `empty`.
*
* Overrides `MapLike` implementation for better efficiency.
*/
override protected[this] def newBuilder: Builder[(A, B), This] = empty
/** Adds a new key/value pair to this map and optionally returns previously bound value.
* If the map already contains a
* mapping for the key, it will be overridden by the new value.
*
* @param key the key to update
* @param value the new value
* @return an option value containing the value associated with the key
* before the `put` operation was executed, or `None` if `key`
* was not defined in the map before.
*/
def put(key: A, value: B): Option[B] = {
val r = get(key)
update(key, value)
r
}
/** Adds a new key/value pair to this map.
* If the map already contains a
* mapping for the key, it will be overridden by the new value.
*
* @param key The key to update
* @param value The new value
*/
def update(key: A, value: B) { this += ((key, value)) }
/** Adds a new key/value pair to this map.
* If the map already contains a
* mapping for the key, it will be overridden by the new value.
* @param kv the key/value pair.
* @return the map itself
*/
def += (kv: (A, B)): this.type
/** Creates a new map consisting of all key/value pairs of the current map
* plus a new pair of a given key and value.
*
* @param key The key to add
* @param value The new value
* @return A fresh immutable map with the binding from `key` to
* `value` added to this map.
*/
override def updated[B1 >: B](key: A, value: B1): Map[A, B1] = this + ((key, value))
/** Add a new key/value mapping and return the map itself.
*
* @param kv the key/value mapping to be added
*/
@migration(2, 8,
"As of 2.8, this operation creates a new map. To add an element as a\n"+
"side effect to an existing map and return that map itself, use +=."
)
def + [B1 >: B] (kv: (A, B1)): Map[A, B1] = clone().asInstanceOf[Map[A, B1]] += kv
/** Adds two or more key/value mappings and return the map itself.
* with the added elements.
*
* @param elem1 the first element to add.
* @param elem2 the second element to add.
* @param elems the remaining elements to add.
*/
@migration(2, 8,
"As of 2.8, this operation creates a new map. To add an element as a\n"+
"side effect to an existing map and return that map itself, use +=."
)
override def + [B1 >: B] (elem1: (A, B1), elem2: (A, B1), elems: (A, B1) *): Map[A, B1] =
clone().asInstanceOf[Map[A, B1]] += elem1 += elem2 ++= elems
/** Adds a number of elements provided by a traversable object
* via its `iterator` method and returns
* either the collection itself (if it is mutable), or a new collection
* with the added elements.
*
* @param iter the traversable object.
*/
@migration(2, 8,
"As of 2.8, this operation creates a new map. To add the elements as a\n"+
"side effect to an existing map and return that map itself, use ++=."
)
override def ++[B1 >: B](xs: TraversableOnce[(A, B1)]): Map[A, B1] =
clone().asInstanceOf[Map[A, B1]] ++= xs
/** Removes a key from this map, returning the value associated previously
* with that key as an option.
* @param key the key to be removed
* @return an option value containing the value associated previously with `key`,
* or `None` if `key` was not defined in the map before.
*/
def remove(key: A): Option[B] = {
val r = get(key)
this -= key
r
}
/** Removes a key from this map.
* @param key the key to be removed
* @return the map itself.
*/
def -= (key: A): this.type
/** Delete a key from this map if it is present and return the map itself.
* @param key the key to be removed
*/
@migration(2, 8,
"As of 2.8, this operation creates a new map. To remove an element as a\n"+
"side effect to an existing map and return that map itself, use -=."
)
override def -(key: A): This = clone() -= key
/** If given key is defined in this map, remove it and return associated value as an Option.
* If key is not present return None.
* @param key the key to be removed
*/
@deprecated("Use `remove' instead") def removeKey(key: A): Option[B] = remove(key)
/** Removes all bindings from the map. After this operation has completed,
* the map will be empty.
*/
def clear() { keysIterator foreach -= }
/** If given key is already in this map, returns associated value
* Otherwise, computes value from given expression `op`, stores with key
* in map and returns that value.
* @param key the key to test
* @param op the computation yielding the value to associate with `key`, if
* `key` is previously unbound.
* @return the value associated with key (either previously or as a result
* of executing the method).
*/
def getOrElseUpdate(key: A, op: => B): B =
get(key) match {
case Some(v) => v
case None => val d = op; this(key) = d; d
}
/** Applies a transformation function to all values contained in this map.
* The transformation function produces new values from existing keys
* associated values.
*
* @param f the transformation to apply
* @return the map itself.
*/
def transform(f: (A, B) => B): this.type = {
this.iterator foreach {
case (key, value) => update(key, f(key, value))
}
this
}
/** Retains only those mappings for which the predicate
* `p` returns `true`.
*
* @param p The test predicate
*/
@deprecated("cannot be type inferred because of retain in Iterable.")
def retain(p: (A, B) => Boolean): this.type = {
for ((k, v) <- this) if (!p(k, v)) -=(k)
this
}
override def clone(): This = empty ++= repr
/** The result when this map is used as a builder
* @return the map representation itself.
*/
def result: This = repr
/** Removes two or more elements from this collection and returns
* the collection itself.
*
* @param elem1 the first element to remove.
* @param elem2 the second element to remove.
* @param elems the remaining elements to remove.
*/
@migration(2, 8,
"As of 2.8, this operation creates a new map. To remove an element as a\n"+
"side effect to an existing map and return that map itself, use -=."
)
override def -(elem1: A, elem2: A, elems: A*): This =
clone() -= elem1 -= elem2 --= elems
/** Removes a number of elements provided by a Traversable object and returns
* the collection itself.
*
* @param iter the Traversable object.
*/
@migration(2, 8,
"As of 2.8, this operation creates a new map. To remove the elements as a\n"+
"side effect to an existing map and return that map itself, use --=."
)
override def --(xs: TraversableOnce[A]): This = clone() --= xs
}
|
