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
262
263
264
265
|
/* __ *\
** ________ ___ / / ___ Scala API **
** / __/ __// _ | / / / _ | (c) 2003-2013, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ **
** /____/\___/_/ |_/____/_/ | | **
** |/ **
\* */
package scala
package collection
package mutable
import generic._
import script._
import scala.annotation.migration
/** A template trait for buffers of type `Buffer[A]`.
*
* Buffers are used to create sequences of elements incrementally by
* appending, prepending, or inserting new elements. It is also
* possible to access and modify elements in a random access fashion
* via the index of the element in the current sequence.
*
* @tparam A the type of the elements of the buffer
* @tparam This the type of the buffer itself.
*
* $buffernote
*
* @author Martin Odersky
* @author Matthias Zenger
* @version 2.8
* @since 2.8
* @define buffernote @note
* This trait provides most of the operations of a `Buffer` independently of its representation.
* It is typically inherited by concrete implementations of buffers.
*
* To implement a concrete buffer, you need to provide implementations of the
* following methods:
* {{{
* def apply(idx: Int): A
* def update(idx: Int, elem: A)
* def length: Int
* def clear()
* def +=(elem: A): this.type
* def +=:(elem: A): this.type
* def insertAll(n: Int, iter: Traversable[A])
* def remove(n: Int): A
* }}}
* @define coll buffer
* @define Coll Buffer
* @define add append
* @define Add Append
* @define willNotTerminateInf
* @define mayNotTerminateInf
* @define compatMutate
* Note that for backward compatibility reasons, this method
* mutates the collection in place, unlike similar but
* undeprecated methods throughout the collections hierarchy.
*/
trait BufferLike[A, +This <: BufferLike[A, This] with Buffer[A]]
extends Growable[A]
with Shrinkable[A]
with Scriptable[A]
with Subtractable[A, This]
with SeqLike[A, This]
with scala.Cloneable
{ self : This =>
// Abstract methods from Seq:
def apply(n: Int): A
def update(n: Int, newelem: A)
def length: Int
// Abstract methods from Growable:
def +=(elem: A): this.type
def clear()
// Abstract methods new in this class:
/** Prepends a single element to this buffer.
* @param elem the element to prepend.
* @return the buffer itself.
*/
def +=:(elem: A): this.type
/** Inserts new elements at a given index into this buffer.
*
* @param n the index where new elements are inserted.
* @param elems the traversable collection containing the elements to insert.
* @throws IndexOutOfBoundsException if the index `n` is not in the valid range
* `0 <= n <= length`.
*/
def insertAll(n: Int, elems: scala.collection.Traversable[A])
/** Removes the element at a given index from this buffer.
*
* @param n the index which refers to the element to delete.
* @return the previous element at index `n`
* @throws IndexOutOfBoundsException if the if the index `n` is not in the valid range
* `0 <= n < length`.
*/
def remove(n: Int): A
/** Removes a number of elements from a given index position. Subclasses of `BufferLike`
* will typically override this method to provide better performance than `count`
* successive calls to single-element `remove`.
*
* @param n the index which refers to the first element to remove.
* @param count the number of elements to remove.
* @throws IndexOutOfBoundsException if the index `n` is not in the valid range
* `0 <= n <= length - count` (with `count > 0`).
* @throws IllegalArgumentException if `count < 0`.
*/
def remove(n: Int, count: Int) {
if (count < 0) throw new IllegalArgumentException("removing negative number of elements: " + count.toString)
for (i <- 0 until count) remove(n)
}
/** Removes a single element from this buffer, at its first occurrence.
* If the buffer does not contain that element, it is unchanged.
*
* @param x the element to remove.
* @return the buffer itself
*/
def -= (x: A): this.type = {
val i = indexOf(x)
if (i != -1) remove(i)
this
}
/** Prepends elements to this buffer.
*
* @param xs the TraversableOnce containing the elements to prepend.
* @return the buffer itself.
*/
def ++=:(xs: TraversableOnce[A]): this.type = { insertAll(0, xs.toTraversable); this }
/** Appends the given elements to this buffer.
*
* @param elems the elements to append.
*/
def append(elems: A*) { appendAll(elems) }
/** Appends the elements contained in a traversable object to this buffer.
* @param xs the traversable object containing the elements to append.
*/
def appendAll(xs: TraversableOnce[A]) { this ++= xs }
/** Prepends given elements to this buffer.
* @param elems the elements to prepend.
*/
def prepend(elems: A*) { prependAll(elems) }
/** Prepends the elements contained in a traversable object to this buffer.
* @param xs the collection containing the elements to prepend.
*/
def prependAll(xs: TraversableOnce[A]) { xs ++=: this }
/** Inserts new elements at a given index into this buffer.
*
* @param n the index where new elements are inserted.
* @param elems the traversable collection containing the elements to insert.
* @throws IndexOutOfBoundsException if the index `n` is not in the valid range
* `0 <= n <= length`.
*/
def insert(n: Int, elems: A*) { insertAll(n, elems) }
/** Removes the first ''n'' elements of this buffer.
*
* @param n the number of elements to remove from the beginning
* of this buffer.
*/
def trimStart(n: Int) { remove(0, n) }
/** Removes the last ''n'' elements of this buffer.
*
* @param n the number of elements to remove from the end
* of this buffer.
*/
def trimEnd(n: Int) { remove(length - n max 0, n) }
/** Send a message to this scriptable object.
*
* @param cmd the message to send.
*/
@deprecated("scripting is deprecated", "2.11.0")
def <<(cmd: Message[A]): Unit = cmd match {
case Include(Start, x) => prepend(x)
case Include(End, x) => append(x)
case Include(Index(n), x) => insert(n, x)
case Include(NoLo, x) => this += x
case Update(Start, x) => update(0, x)
case Update(End, x) => update(length - 1, x)
case Update(Index(n), x) => update(n, x)
case Remove(Start, x) => if (this(0) == x) remove(0)
case Remove(End, x) => if (this(length - 1) == x) remove(length - 1)
case Remove(Index(n), x) => if (this(n) == x) remove(n)
case Remove(NoLo, x) => this -= x
case Reset() => clear()
case s: Script[_] => s.iterator foreach <<
case _ => throw new UnsupportedOperationException("message " + cmd + " not understood")
}
/** Defines the prefix of this object's `toString` representation.
* @return a string representation which starts the result of `toString` applied to this set.
* Unless overridden this is simply `"Buffer"`.
*/
override def stringPrefix: String = "Buffer"
/** Creates a new collection containing both the elements of this collection and the provided
* traversable object.
*
* @param xs the traversable object.
* @return a new collection consisting of all the elements of this collection and `xs`.
*/
@migration("`++` creates a new buffer. Use `++=` to add an element from this buffer and return that buffer itself.", "2.8.0")
def ++(xs: GenTraversableOnce[A]): This = clone() ++= xs.seq
/** Creates a new collection with all the elements of this collection except `elem`.
*
* @param elem the element to remove.
* @return a new collection consisting of all the elements of this collection except `elem`.
*/
@migration("`-` creates a new buffer. Use `-=` to remove an element from this buffer and return that buffer itself.", "2.8.0")
override def -(elem: A): This = clone() -= elem
/** Creates a new collection with all the elements of this collection except the two
* or more specified elements.
*
* @param elem1 the first element to remove.
* @param elem2 the second element to remove.
* @param elems the remaining elements to remove.
* @return a new collection consisting of all the elements of this collection except
* `elem1`, `elem2` and those in `elems`.
*/
@migration("`-` creates a new buffer. Use `-=` to remove an element from this buffer and return that buffer itself.", "2.8.0")
override def -(elem1: A, elem2: A, elems: A*): This = clone() -= elem1 -= elem2 --= elems
/** Creates a new collection with all the elements of this collection except those
* provided by the specified traversable object.
*
* @param xs the traversable object.
* @return a new collection with all the elements of this collection except
* those in `xs`
*/
@migration("`--` creates a new buffer. Use `--=` to remove an element from this buffer and return that buffer itself.", "2.8.0")
override def --(xs: GenTraversableOnce[A]): This = clone() --= xs.seq
/** Return a clone of this buffer.
*
* @return a `Buffer` with the same elements.
*/
override def clone(): This = {
val bf = newBuilder
bf ++= this
bf.result().asInstanceOf[This]
}
}
|
