blob: 54619287354fb942cb3d985d45f628385822a369 (
plain) (
blame)
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
|
/* __ *\
** ________ ___ / / ___ Scala API **
** / __/ __// _ | / / / _ | (c) 2006-2007, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ | **
** /____/\___/_/ |_/____/_/ | | **
** |/ **
\* */
// $Id$
package scala.collection.jcl;
/** An iterator for a sequence that can move both forwards and backwards.
* over a set of ordered keys.
*
* @author Sean McDirmid
*/
trait SeqIterator[K,A] extends MutableIterator[A] {
/** @returns The index at the iterator's cursor. */
def nextIndex: K;
/** @returns The index of the element before the iterator's cursor. */
def previousIndex: K;
/** @return The previous element, will move the iterator's cursor backwards. */
def previous: A;
/** @return True if and only if the iterator's cursor is not at the beging of the iteration. */
def hasPrevious : Boolean;
/** Winds the iteration forward until index "idx" is found */
def seek(idx: K) = {
while (nextIndex != idx) next;
next;
}
/** finds the index of the next "a" in this iteration.
*
* @param a ..
* @return <code>None</code> if "a" is not found in the iteration.
*/
def indexOf(a: A): Option[K] = {
while (hasNext) {
val ret = next;
if (ret == a) return Some(previousIndex);
}
return None;
}
override def map[B](f: A => B) : SeqIterator[K,B] = new Map[B](f);
class Map[B](f: A => B) extends super.Map[B](f) with SeqIterator[K,B] {
override def hasPrevious = SeqIterator.this.hasPrevious;
override def previous = f(SeqIterator.this.previous);
override def previousIndex = SeqIterator.this.previousIndex;
override def nextIndex = SeqIterator.this.nextIndex;
override def map[C](g : B => C) : SeqIterator[K,C] =
SeqIterator.this.map(a => g(f(a)));
}
}
|
