java.lang.Object | ||
java.util.Collections |
Collections contains static methods which operate on Collection classes.
Value | ||||
---|---|---|---|---|
List | EMPTY_LIST | |||
Map | EMPTY_MAP | |||
Set | EMPTY_SET |
static | <T> | boolean | addAll(Collection<? super T> c, T[] a) | |||
Adds all the specified elements to the specified collection | ||||||
static | <T> | int | binarySearch(List<? extends Comparable<? super T>> list, T object) | |||
Performs a binary search for the specified element in the specified sorted List. | ||||||
static | <T> | int | binarySearch(List<? extends T> list, T object, Comparator<? super T> comparator) | |||
Performs a binary search for the specified element in the specified sorted List using the specified Comparator. | ||||||
static | <E> | Collection<E> | checkedCollection(Collection<E> c, Class<E> type) | |||
Returns a dynamically typesafe view of the specified collection. | ||||||
static | <E> | List<E> | checkedList(List<E> list, Class<E> type) | |||
Returns a dynamically typesafe view of the specified list. | ||||||
static | <K, V> | Map<K, V> | checkedMap(Map<K, V> m, Class<K> keyType, Class<V> valueType) | |||
Returns a dynamically typesafe view of the specified map. | ||||||
static | <E> | Set<E> | checkedSet(Set<E> s, Class<E> type) | |||
Returns a dynamically typesafe view of the specified set. | ||||||
static | <K, V> | SortedMap<K, V> | checkedSortedMap(SortedMap<K, V> m, Class<K> keyType, Class<V> valueType) | |||
Returns a dynamically typesafe view of the specified sorted map. | ||||||
static | <E> | SortedSet<E> | checkedSortedSet(SortedSet<E> s, Class<E> type) | |||
Returns a dynamically typesafe view of the specified sorted set. | ||||||
static | <T> | void | copy(List<? super T> destination, List<? extends T> source) | |||
Copies the elements from the source list to the destination list. | ||||||
static | boolean | disjoint(Collection<?> c1, Collection<?> c2) | ||||
Returns true if the collections have no elements in common | ||||||
final | static | <T> | List<T> | emptyList() | ||
Returns a type-safe empty, immutable List. | ||||||
final | static | <K, V> | Map<K, V> | emptyMap() | ||
Returns a type-safe empty, immutable Map. | ||||||
final | static | <T> | Set<T> | emptySet() | ||
Returns a type-safe empty, immutable Set. | ||||||
static | <T> | Enumeration<T> | enumeration(Collection<T> collection) | |||
Returns an Enumeration on the specified Collection. | ||||||
static | <T> | void | fill(List<? super T> list, T object) | |||
Fills the specified List with the specified element. | ||||||
static | int | frequency(Collection<?> c, Object o) | ||||
Returns the number of elements in the |
||||||
static | int | indexOfSubList(List<?> list, List<?> sublist) | ||||
Searches the list for sublist and returns
the beginning index of the first occurrence. |
||||||
static | int | lastIndexOfSubList(List<?> list, List<?> sublist) | ||||
Searches the list for sublist and returns
the beginning index of the last occurrence. |
||||||
static | <T> | ArrayList<T> | list(Enumeration<T> enumeration) | |||
Returns an ArrayList with all the elements in the
enumeration . |
||||||
static | <T extends Object & Comparable<? super T>> | T | max(Collection<? extends T> collection) | |||
Searches the specified Collection for the maximum element. | ||||||
static | <T> | T | max(Collection<? extends T> collection, Comparator<? super T> comparator) | |||
Searches the specified Collection for the maximum element using the specified Comparator. | ||||||
static | <T extends Object & Comparable<? super T>> | T | min(Collection<? extends T> collection) | |||
Searches the specified Collection for the minimum element. | ||||||
static | <T> | T | min(Collection<? extends T> collection, Comparator<? super T> comparator) | |||
Searches the specified Collection for the minimum element using the specified Comparator. | ||||||
static | <T> | List<T> | nCopies(int length, T object) | |||
Returns a List containing the specified number of the specified element. | ||||||
static | <T> | boolean | replaceAll(List<T> list, T obj, T obj2) | |||
Replaces all occurrences of Object obj in
list with newObj . |
||||||
static | void | reverse(List<?> list) | ||||
Returns the supplied List with the order of its contained
elements reversed. |
||||||
static | <T> | Comparator<T> | reverseOrder(Comparator<T> c) | |||
Returns a Comparator that reverses the order of the
|
||||||
static | <T> | Comparator<T> | reverseOrder() | |||
A Comparator which reverses the natural order of the elements. |
||||||
static | void | rotate(List<?> lst, int dist) | ||||
Rotates the elements in List list by the distance
dist
e.g. |
||||||
static | void | shuffle(List<?> list) | ||||
Moves every element of the List to a random new position in the list. | ||||||
static | void | shuffle(List<?> list, Random random) | ||||
Moves every element of the List to a random new position in the list using the specified random number generator. | ||||||
static | <E> | Set<E> | singleton(E object) | |||
Returns a Set containing the specified element. | ||||||
static | <E> | List<E> | singletonList(E object) | |||
Returns a List containing the specified element. | ||||||
static | <K, V> | Map<K, V> | singletonMap(K key, V value) | |||
Returns a Map containing the specified key and value. | ||||||
static | <T> | void | sort(List<T> list, Comparator<? super T> comparator) | |||
Sorts the specified List using the specified Comparator. | ||||||
static | <T extends Comparable<? super T>> | void | sort(List<T> list) | |||
Sorts the specified List in ascending order. | ||||||
static | void | swap(List<?> list, int index1, int index2) | ||||
Swaps the elements of List list at indices
index1 and index2 |
||||||
static | <T> | Collection<T> | synchronizedCollection(Collection<T> collection) | |||
Returns a wrapper on the specified Collection which synchronizes all access to the Collection. | ||||||
static | <T> | List<T> | synchronizedList(List<T> list) | |||
Returns a wrapper on the specified List which synchronizes all access to the List. | ||||||
static | <K, V> | Map<K, V> | synchronizedMap(Map<K, V> map) | |||
Returns a wrapper on the specified Map which synchronizes all access to the Map. | ||||||
static | <E> | Set<E> | synchronizedSet(Set<E> set) | |||
Returns a wrapper on the specified Set which synchronizes all access to the Set. | ||||||
static | <K, V> | SortedMap<K, V> | synchronizedSortedMap(SortedMap<K, V> map) | |||
Returns a wrapper on the specified SortedMap which synchronizes all access to the SortedMap. | ||||||
static | <E> | SortedSet<E> | synchronizedSortedSet(SortedSet<E> set) | |||
Returns a wrapper on the specified SortedSet which synchronizes all access to the SortedSet. | ||||||
static | <E> | Collection<E> | unmodifiableCollection(Collection<? extends E> collection) | |||
Returns a wrapper on the specified Collection which throws an
UnsupportedOperationException whenever an attempt is made
to modify the Collection. |
||||||
static | <E> | List<E> | unmodifiableList(List<? extends E> list) | |||
Returns a wrapper on the specified List which throws an
UnsupportedOperationException whenever an attempt is made
to modify the List. |
||||||
static | <K, V> | Map<K, V> | unmodifiableMap(Map<? extends K, ? extends V> map) | |||
Returns a wrapper on the specified Map which throws an
UnsupportedOperationException whenever an attempt is made
to modify the Map. |
||||||
static | <E> | Set<E> | unmodifiableSet(Set<? extends E> set) | |||
Returns a wrapper on the specified Set which throws an
UnsupportedOperationException whenever an attempt is made
to modify the Set. |
||||||
static | <K, V> | SortedMap<K, V> | unmodifiableSortedMap(SortedMap<K, ? extends V> map) | |||
Returns a wrapper on the specified SortedMap which throws an
UnsupportedOperationException whenever an attempt is made
to modify the SortedMap. |
||||||
static | <E> | SortedSet<E> | unmodifiableSortedSet(SortedSet<E> set) | |||
Returns a wrapper on the specified SortedSet which throws an
UnsupportedOperationException whenever an attempt is made
to modify the SortedSet. |
c | the collection the elements are to be inserted into |
---|---|
a | the elements to insert |
UnsupportedOperationException | when the method is not supported |
---|---|
NullPointerException | when c or elements is null, or elements contains one or more null elements and c doesn't support null elements |
list | the sorted List to search |
---|---|
object | the element to find |
ClassCastException | when an element in the List or the search element does not implement Comparable, or cannot be compared to each other |
---|
list | the sorted List to search |
---|---|
object | the element to find |
comparator | the Comparator. If the comparator is null then
the search uses the objects' natural ordering. |
ClassCastException | when an element in the list and the searched element cannot be compared to each other using the Comparator |
---|
c | the collection |
---|---|
type | the type of the elements permitted to insert |
list | the list |
---|---|
type | the type of the elements permitted to insert |
m | the map |
---|---|
keyType | the type of the keys permitted to insert |
valueType | the type of the values permitted to insert |
s | the set |
---|---|
type | the type of the elements permitted to insert |
m | the sorted map |
---|---|
keyType | the type of the keys permitted to insert |
valueType | the type of the values permitted to insert |
s | the sorted set |
---|---|
type | the type of the elements permitted to insert |
IndexOutOfBoundsException | when the destination List is smaller than the source List |
---|---|
UnsupportedOperationException | when replacing an element in the destination list is not supported |
c1 | the first collection |
---|---|
c2 | the second collection |
NullPointerException | if one of the collections is null |
---|
collection | the Collection to enumerate |
---|
list | the List to fill |
---|---|
object | the fill element |
UnsupportedOperationException | when replacing an element in the List is not supported |
---|
Returns the number of elements in the Collection
that
match the Object
passed. If the Object
is
null
, then the number of null
elements is
returned.
c | The Collection to search. |
---|---|
o | The Object to search for. |
NullPointerException | if the Collection parameter is
null . |
---|
list
for sublist
and returns
the beginning index of the first occurrence.
-1 is returned if the sublist
does not exist in
list
list | the List to search sublist in |
---|---|
sublist | the List to search in list |
sublist
in list
, or -1
list
for sublist
and returns
the beginning index of the last occurrence.
-1 is returned if the sublist
does not exist in
list
list | the List to search sublist in |
---|---|
sublist | the List to search in list |
sublist
in list
, or -1
enumeration
. The elements in the returned ArrayList are
in the same order as in the enumeration
.
enumeration | Enumeration |
---|
collection | the Collection to search |
---|
ClassCastException | when an element in the Collection does not implement Comparable or elements cannot be compared to each other |
---|
collection | the Collection to search |
---|---|
comparator | the Comparator |
ClassCastException | when elements in the Collection cannot be compared to each other using the Comparator |
---|
collection | the Collection to search |
---|
ClassCastException | when an element in the Collection does not implement Comparable or elements cannot be compared to each other |
---|
collection | the Collection to search |
---|---|
comparator | the Comparator |
ClassCastException | when elements in the Collection cannot be compared to each other using the Comparator |
---|
length | the size of the returned List |
---|---|
object | the element |
length
copies of the elementIllegalArgumentException | when length < 0
|
---|
obj
in
list
with newObj
. If the obj
is null
, then all occurrences of null
is
replaced with newObj
.
list | the List to modify |
---|---|
obj | the Object to find and replace occurrences of. |
obj2 | the Object to replace all occurrences of obj in
list |
obj
has been
found in list
UnsupportedOperationException | if the list does not support setting elements |
---|
List
with the order of its contained
elements reversed.
list | the List to reverse |
---|
UnsupportedOperationException | when replacing an element in the List is not supported |
---|
Returns a Comparator that reverses the order of the
Comparator
passed. If the Comparator
passed
is null
, then this method is equivalent to
reverseOrder().
The Comparator
that's returned is Serializable if
the Comparator
passed is serializable or null
.
c | The Comparator to reverse or null . |
---|
Comparator
instance.
A Comparator which reverses the natural order of the elements. The
Comparator
that's returned is Serializable.
Comparator
instance.list
by the distance
dist
e.g. for a given list with elements [1, 2, 3, 4, 5, 6, 7, 8, 9, 0], calling rotate(list, 3) or rotate(list, -7) would modify the list to look like this: [8, 9, 0, 1, 2, 3, 4, 5, 6, 7]
dist | It can be any integer: 0, positive, negative, larger than the list size |
---|
list | the List to shuffle |
---|
UnsupportedOperationException | when replacing an element in the List is not supported |
---|
list | the List to shuffle |
---|---|
random | the random number generator |
UnsupportedOperationException | when replacing an element in the List is not supported |
---|
object | the element |
---|
object | the element |
---|
key | the key |
---|---|
value | the value |
list | the List to be sorted |
---|---|
comparator | the Comparator |
ClassCastException | when elements in the List cannot be compared to each other using the Comparator |
---|
list | the List to be sorted |
---|
ClassCastException | when an element in the List does not implement Comparable or elements cannot be compared to each other |
---|
list
at indices
index1
and index2
list | the List to manipulate on |
---|---|
index1 | int position of the first element to swap with the element in index2 |
index2 | int position of the other element |
IndexOutOfBoundsException | if index1 or index2 is out of range of this list |
---|
collection | the Collection |
---|
list | the List |
---|
map | the Map |
---|
set | the Set |
---|
map | the SortedMap |
---|
set | the SortedSet |
---|
UnsupportedOperationException
whenever an attempt is made
to modify the Collection.
collection | the Collection |
---|
UnsupportedOperationException
whenever an attempt is made
to modify the List.
list | the List |
---|
UnsupportedOperationException
whenever an attempt is made
to modify the Map.
map | the Map |
---|
UnsupportedOperationException
whenever an attempt is made
to modify the Set.
set | the Set |
---|
UnsupportedOperationException
whenever an attempt is made
to modify the SortedMap.
map | the SortedMap |
---|
Copyright 2007 Google Inc. | Build 0.9_r1-98467 - 14 Aug 2008 18:56 |