1 # This file is part of NIT ( http://www.nitlanguage.org ).
3 # Copyright 2004-2008 Jean Privat <jean@pryen.org>
5 # This file is free software, which comes along with NIT. This software is
6 # distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
7 # without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
8 # PARTICULAR PURPOSE. You can modify it is you want, provided this header
9 # is kept unaltered, and a notification of the changes is added.
10 # You are allowed to redistribute it and sell it, alone or is a part of
13 # This module define several abstract collection classes.
14 module abstract_collection
18 # The root of the collection hierarchy.
20 # Collections modelize finite groups of objects, called elements.
22 # The specific behavior and representation of collections is determined
23 # by the subclasses of the hierarchy.
25 # The main service of Collection is to provide a stable `iterator`
26 # method usable to retrieve all the elements of the collection.
28 # Additional services are provided.
29 # For an implementation point of view, Collection provide a basic
30 # implementation of these services using the `iterator` method.
31 # Subclasses often provide a more efficient implementation.
33 # Because of the `iterator` method, Collections instances can use
34 # the `for` control structure:
36 # var x: Collection[U]
43 # that is equivalent with
45 # var x: Collection[U]
49 # var u = i.item # u is a U
53 interface Collection[E
]
54 # Get a new iterator on the collection.
55 fun iterator
: Iterator[E
] is abstract
57 # Iterate over each element of the collection
68 # Is there no item in the collection?
70 # assert [1,2,3].is_empty == false
71 # assert [1..1[.is_empty == true
72 fun is_empty
: Bool do return length
== 0
74 # Number of items in the collection.
76 # assert [10,20,30].length == 3
77 # assert [20..30[.length == 10
81 for i
in self do nb
+= 1
86 # Is `item` in the collection ?
87 # Comparisons are done with ==
89 # assert [1,2,3].has(2) == true
90 # assert [1,2,3].has(9) == false
91 # assert [1..5[.has(2) == true
92 # assert [1..5[.has(9) == false
93 fun has
(item
: E
): Bool
95 for i
in self do if i
== item
then return true
99 # Is the collection contain only `item`?
100 # Comparisons are done with ==
101 # Return true if the collection is empty.
103 # assert [1,1,1].has_only(1) == true
104 # assert [1,2,3].has_only(1) == false
105 # assert [1..1].has_only(1) == true
106 # assert [1..3].has_only(1) == false
107 # assert [3..3[.has_only(1) == true # empty collection
109 # ENSURE `is_empty implies result == true`
110 fun has_only
(item
: E
): Bool
112 for i
in self do if i
!= item
then return false
116 # How many occurrences of `item` are in the collection?
117 # Comparisons are done with ==
119 # assert [10,20,10].count(10) == 2
120 fun count
(item
: E
): Int
123 for i
in self do if i
== item
then nb
+= 1
127 # Return one the item of the collection
129 # assert [1,2,3].first == 1
136 # Is the collection contains all the elements of `other`?
138 # assert [1,1,1].has_all([1]) == true
139 # assert [1,1,1].has_all([1,2]) == false
140 # assert [1,3,4,2].has_all([1..2]) == true
141 # assert [1,3,4,2].has_all([1..5]) == false
142 fun has_all
(other
: Collection[E
]): Bool
144 for x
in other
do if not has
(x
) then return false
149 # Instances of the Iterator class generates a series of elements, one at a time.
150 # They are mainly used with collections.
151 interface Iterator[E
]
154 fun item
: E
is abstract
156 # Jump to the next item.
160 # Is there a current item ?
161 fun is_ok
: Bool is abstract
164 # A collection that contains only one item.
168 redef fun first
do return _item
170 redef fun is_empty
do return false
172 redef fun length
do return 1
174 redef fun has
(an_item
) do return _item
== an_item
176 redef fun has_only
(an_item
) do return _item
== an_item
178 redef fun count
(an_item
)
180 if _item
== an_item
then
187 redef fun iterator
do return new ContainerIterator[E
](self)
189 # Create a new instance with a given initial value.
190 init(e
: E
) do _item
= e
193 readable writable var _item
: E
196 # This iterator is quite stupid since it is used for only one item.
197 class ContainerIterator[E
]
199 redef fun item
do return _container
.item
201 redef fun next
do _is_ok
= false
203 init(c
: Container[E
]) do _container
= c
205 redef readable var _is_ok
: Bool = true
207 var _container
: Container[E
]
210 # Items can be removed from this collection
211 interface RemovableCollection[E
]
214 fun clear
is abstract
216 # Remove an occucence of `item`
217 fun remove
(item
: E
) is abstract
219 # Remove all occurences of `item`
220 fun remove_all
(item
: E
) do while has
(item
) do remove
(item
)
223 # Items can be added to these collections.
224 interface SimpleCollection[E
]
225 super RemovableCollection[E
]
226 # Add an item in a collection.
227 # Ensure col.has(item)
228 fun add
(item
: E
) is abstract
230 # Add each item of `coll`.
231 fun add_all
(coll
: Collection[E
]) do for i
in coll
do add
(i
)
236 # Set contains contains only one element with the same value (according to ==).
237 # var s: Set[String] = new ArraySet[String]
239 # var b = "Hel" + "lo"
242 # assert s.has(b) == true
243 interface Set[E
: Object]
244 super SimpleCollection[E
]
246 redef fun has_only
(item
)
259 redef fun count
(item
)
268 # Synonym of remove since there is only one item
269 redef fun remove_all
(item
) do remove
(item
)
271 # Equality is defined on set and means that each set contains the same elements
274 if not other
isa Set[Object] then return false
275 if other
.length
!= length
then return false
276 return has_all
(other
)
280 # MapRead are abstract associative collections: `key` -> `item`.
281 interface MapRead[K
: Object, E
]
282 # Get the item at `key`.
283 fun [](key
: K
): E
is abstract
285 # Get the item at `key` or return `default` if not in map
286 fun get_or_default
(key
: K
, default
: E
): E
288 if has_key
(key
) then return self[key
]
292 # Depreciated alias for `keys.has`
293 fun has_key
(key
: K
): Bool do return self.keys
.has
(key
)
295 # Get a new iterator on the map.
296 fun iterator
: MapIterator[K
, E
] is abstract
298 # Iterate over each element of the collection
309 # Return the point of view of self on the values only.
310 # Note that `self` and `values` are views on the same data;
311 # therefore any modification of one is visible on the other.
312 fun values
: Collection[E
] is abstract
314 # Return the point of view of self on the keys only.
315 # Note that `self` and `keys` are views on the same data;
316 # therefore any modification of one is visible on the other.
317 fun keys
: Collection[K
] is abstract
319 # Is there no item in the collection?
320 fun is_empty
: Bool is abstract
322 # Number of items in the collection.
323 fun length
: Int is abstract
326 # Maps are associative collections: `key` -> `item`.
328 # The main operator over maps is [].
330 # var map: Map[String, Int] = new ArrayMap[String, Int]
332 # map["one"] = 1 # Associate 'one' to '1'
333 # map["two"] = 2 # Associate 'two' to '2'
334 # assert map["one"] == 1
335 # assert map["two"] == 2
337 # Instances of maps can be used with the for structure
339 # for key, value in map do
340 # assert (key == "one" and value == 1) or (key == "two" and value == 2)
343 # The keys and values in the map can also be manipulated directly with the `keys` and `values` methods.
345 # assert map.keys.has("one") == true
346 # assert map.keys.has("tree") == false
347 # assert map.values.has(1) == true
348 # assert map.values.has(3) == false
350 interface Map[K
: Object, E
]
352 # Set the`item` at `key`.
353 fun []=(key
: K
, item
: E
) is abstract
355 # Add each (key,value) of `map` into `self`.
356 # If a same key exists in `map` and `self`, then the value in self is discarded.
357 fun recover_with
(map
: Map[K
, E
])
367 fun clear
is abstract
369 redef fun values
: RemovableCollection[E
] is abstract
371 redef fun keys
: RemovableCollection[K
] is abstract
375 interface MapIterator[K
: Object, E
]
378 fun item
: E
is abstract
380 # The key of the current item.
382 fun key
: K
is abstract
384 # Jump to the next item.
388 # Is there a current item ?
389 fun is_ok
: Bool is abstract
391 # Set a new `item` at `key`.
392 #fun item=(item: E) is abstract
395 # Iterator on a 'keys' point of view of a map
396 class MapKeysIterator[K
: Object, V
]
398 # The original iterator
399 var iterator
: MapIterator[K
, V
]
401 redef fun is_ok
do return self.iterator
.is_ok
402 redef fun next
do self.iterator
.next
403 redef fun item
do return self.iterator
.key
406 # Iterator on a 'values' point of view of a map
407 class MapValuesIterator[K
: Object, V
]
409 # The original iterator
410 var iterator
: MapIterator[K
, V
]
412 redef fun is_ok
do return self.iterator
.is_ok
413 redef fun next
do self.iterator
.next
414 redef fun item
do return self.iterator
.item
417 # Sequences are indexed collections.
418 # The first item is 0. The last is `length-1`.
419 interface SequenceRead[E
]
421 # Get the first item.
422 # Is equivalent with `self[0]`.
425 assert not_empty
: not is_empty
429 # Return the index=th element of the sequence.
430 # The first element is 0 and the last if `length-1`
431 # If index is invalid, the program aborts
432 fun [](index
: Int): E
is abstract
435 # Is equivalent with `self[length-1]`.
438 assert not_empty
: not is_empty
439 return self[length-1
]
442 # Return the index of the first occurrence of `item`.
443 # Return -1 if `item` is not found
444 # Comparison is done with ==
445 fun index_of
(item
: E
): Int
449 if i
.item
== item
then return i
.index
455 redef fun iterator
: IndexedIterator[E
] is abstract
458 # Sequence are indexed collection.
459 # The first item is 0. The last is `length-1`.
460 interface Sequence[E
]
461 super SequenceRead[E
]
462 super SimpleCollection[E
]
464 # Set the first item.
465 # Is equivalent with `self[0] = item`.
467 do self[0] = item
end
470 # Is equivalent with `self[length-1] = item`.
481 # A synonym of `push`
482 redef fun add
(e
) do push
(e
)
484 # Add an item after the last.
485 fun push
(e
: E
) is abstract
487 # Add each item of `coll` after the last.
488 fun append
(coll
: Collection[E
]) do for i
in coll
do push
(i
)
490 # Remove the last item.
491 fun pop
: E
is abstract
493 # Add an item before the last.
494 fun unshift
(e
: E
) is abstract
496 # Remove the first item.
497 # The second item become the first.
498 fun shift
: E
is abstract
500 # Set the `item` at `index`.
501 fun []=(index
: Int, item
: E
) is abstract
503 # Remove the item at `index` and shift all following elements
504 fun remove_at
(index
: Int) is abstract
507 # Iterators on indexed collections.
508 interface IndexedIterator[E
]
510 # The index of the current item.
511 fun index
: Int is abstract
514 # Associative arrays that internally uses couples to represent each (key, value) pairs.
515 interface CoupleMap[K
: Object, E
]
517 # Return the couple of the corresponding key
518 # Return null if the key is no associated element
519 protected fun couple_at
(key
: K
): nullable Couple[K
, E
] is abstract
523 var c
= couple_at
(key
)
532 # Iterator on CoupleMap
534 # Actually is is a wrapper around an iterator of the internal array of the map.
535 class CoupleMapIterator[K
: Object, E
]
536 super MapIterator[K
, E
]
537 redef fun item
do return _iter
.item
.second
539 #redef fun item=(e) do _iter.item.second = e
541 redef fun key
do return _iter
.item
.first
543 redef fun is_ok
do return _iter
.is_ok
550 var _iter
: Iterator[Couple[K
,E
]]
552 init(i
: Iterator[Couple[K
,E
]]) do _iter
= i
555 # Some tools ###################################################################
557 # Two objects in a simple structure.
560 # The first element of the couple.
561 readable writable var _first
: F
563 # The second element of the couple.
564 readable writable var _second
: S
566 # Create a new instance with a first and a second object.