java.lang.Object | |
↳ | java.util.AbstractCollection<E> |
Known Direct Subclasses
|
Known Indirect Subclasses
AbstractSequentialList<E>,
ArrayBlockingQueue<E>,
ArrayList<E>,
ConcurrentLinkedQueue<E>,
ConcurrentSkipListSet<E>,
CopyOnWriteArraySet<E>,
DelayQueue<E extends Delayed>,
EnumSet<E extends Enum<E>>,
HashSet<E>,
LinkedBlockingDeque<E>,
LinkedBlockingQueue<E>,
LinkedHashSet<E>,
LinkedList<E>,
PriorityBlockingQueue<E>,
PriorityQueue<E>,
Stack<E>,
SynchronousQueue<E>,
TreeSet<E>,
Vector<E>
|
Class AbstractCollection
is an abstract implementation of the Collection
interface. A subclass must implement the abstract methods iterator()
and size()
to create an immutable collection. To create a
modifiable collection it's necessary to override the add()
method that
currently throws an UnsupportedOperationException
.
Protected Constructors | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Constructs a new instance of this AbstractCollection.
|
Public Methods | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Attempts to add
object to the contents of this
Collection (optional). | |||||||||||
Attempts to add all of the objects contained in
collection
to the contents of this Collection (optional). | |||||||||||
Removes all elements from this
Collection , leaving it empty (optional). | |||||||||||
Tests whether this
Collection contains the specified object. | |||||||||||
Tests whether this
Collection contains all objects contained in the
specified Collection . | |||||||||||
Returns if this
Collection contains no elements. | |||||||||||
Returns an instance of
Iterator that may be used to access the
objects contained by this Collection . | |||||||||||
Removes one instance of the specified object from this
Collection if one
is contained (optional). | |||||||||||
Removes all occurrences in this
Collection of each object in the
specified Collection (optional). | |||||||||||
Removes all objects from this
Collection that are not also found in the
Collection passed (optional). | |||||||||||
Returns a count of how many objects this
Collection contains. | |||||||||||
Returns an array containing all elements contained in this
Collection . | |||||||||||
Returns a new array containing all elements contained in this
Collection . | |||||||||||
Returns the string representation of this
Collection . |
[Expand]
Inherited Methods | |||||||||||
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From class
java.lang.Object
| |||||||||||
From interface
java.lang.Iterable
| |||||||||||
From interface
java.util.Collection
|
Constructs a new instance of this AbstractCollection.
Attempts to add object
to the contents of this
Collection
(optional).
After this method finishes successfully it is guaranteed that the object
is contained in the collection.
If the collection was modified it returns true
, false
if
no changes were made.
An implementation of Collection
may narrow the set of accepted
objects, but it has to specify this in the documentation. If the object
to be added does not meet this restriction, then an
IllegalArgumentException
is thrown.
If a collection does not yet contain an object that is to be added and
adding the object fails, this method must throw an appropriate
unchecked Exception. Returning false is not permitted in this case
because it would violate the postcondition that the element will be part
of the collection after this method finishes.
object | the object to add. |
---|
true
if this Collection
is
modified, false
otherwise.Attempts to add all of the objects contained in collection
to the contents of this Collection
(optional). This implementation
iterates over the given Collection
and calls add
for each
element. If any of these calls return true
, then true
is
returned as result of this method call, false
otherwise. If this
Collection
does not support adding elements, an UnsupportedOperationException
is thrown.
If the passed Collection
is changed during the process of adding elements
to this Collection
, the behavior depends on the behavior of the passed
Collection
.
collection | the collection of objects. |
---|
true
if this Collection
is modified, false
otherwise.UnsupportedOperationException | if adding to this Collection is not supported. |
---|---|
ClassCastException | if the class of an object is inappropriate for this
Collection . |
IllegalArgumentException | if an object cannot be added to this Collection . |
NullPointerException | if collection is null , or if it contains
null elements and this Collection does not support
such elements.
|
Removes all elements from this Collection
, leaving it empty (optional).
This implementation iterates over this Collection
and calls the remove
method on each element. If the iterator does not support removal
of elements, an UnsupportedOperationException
is thrown.
Concrete implementations usually can clear a Collection
more efficiently
and should therefore overwrite this method.
UnsupportedOperationException | it the iterator does not support removing elements from
this Collection |
---|
Tests whether this Collection
contains the specified object. This
implementation iterates over this Collection
and tests, whether any
element is equal to the given object. If object != null
then
object.equals(e)
is called for each element e
returned by
the iterator until the element is found. If object == null
then
each element e
returned by the iterator is compared with the test
e == null
.
object | the object to search for. |
---|
true
if object is an element of this Collection
, false
otherwise.ClassCastException | if the object to look for isn't of the correct type. |
---|---|
NullPointerException | if the object to look for is null and this
Collection doesn't support null elements.
|
Tests whether this Collection
contains all objects contained in the
specified Collection
. This implementation iterates over the specified
Collection
. If one element returned by the iterator is not contained in
this Collection
, then false
is returned; true
otherwise.
collection | the collection of objects. |
---|
true
if all objects in the specified Collection
are
elements of this Collection
, false
otherwise.ClassCastException | if one or more elements of collection isn't of the
correct type. |
---|---|
NullPointerException | if collection contains at least one null
element and this Collection doesn't support null
elements. |
NullPointerException | if collection is null .
|
Returns if this Collection
contains no elements. This implementation
tests, whether size
returns 0.
true
if this Collection
has no elements, false
otherwise.Returns an instance of Iterator
that may be used to access the
objects contained by this Collection
. The order in which the elements are
returned by the Iterator
is not defined unless the instance of the
Collection
has a defined order. In that case, the elements are returned in that order.
In this class this method is declared abstract and has to be implemented
by concrete Collection
implementations.
Collection
contents.
Removes one instance of the specified object from this Collection
if one
is contained (optional). This implementation iterates over this
Collection
and tests for each element e
returned by the iterator,
whether e
is equal to the given object. If object != null
then this test is performed using object.equals(e)
, otherwise
using object == null
. If an element equal to the given object is
found, then the remove
method is called on the iterator and
true
is returned, false
otherwise. If the iterator does
not support removing elements, an UnsupportedOperationException
is thrown.
object | the object to remove. |
---|
true
if this Collection
is modified, false
otherwise.UnsupportedOperationException | if removing from this Collection is not supported. |
---|---|
ClassCastException | if the object passed is not of the correct type. |
NullPointerException | if object is null and this Collection
doesn't support null elements.
|
Removes all occurrences in this Collection
of each object in the
specified Collection
(optional). After this method returns none of the
elements in the passed Collection
can be found in this Collection
anymore.
This implementation iterates over this Collection
and tests for each
element e
returned by the iterator, whether it is contained in
the specified Collection
. If this test is positive, then the remove
method is called on the iterator. If the iterator does not
support removing elements, an UnsupportedOperationException
is
thrown.
collection | the collection of objects to remove. |
---|
true
if this Collection
is modified, false
otherwise.UnsupportedOperationException | if removing from this Collection is not supported. |
---|---|
ClassCastException | if one or more elements of collection isn't of the
correct type. |
NullPointerException | if collection contains at least one null
element and this Collection doesn't support null
elements. |
NullPointerException | if collection is null .
|
Removes all objects from this Collection
that are not also found in the
Collection
passed (optional). After this method returns this Collection
will only contain elements that also can be found in the Collection
passed to this method.
This implementation iterates over this Collection
and tests for each
element e
returned by the iterator, whether it is contained in
the specified Collection
. If this test is negative, then the remove
method is called on the iterator. If the iterator does not
support removing elements, an UnsupportedOperationException
is
thrown.
collection | the collection of objects to retain. |
---|
true
if this Collection
is modified, false
otherwise.UnsupportedOperationException | if removing from this Collection is not supported. |
---|---|
ClassCastException | if one or more elements of collection
isn't of the correct type. |
NullPointerException | if collection contains at least one
null element and this Collection doesn't support
null elements. |
NullPointerException | if collection is null .
|
Returns a count of how many objects this Collection
contains.
In this class this method is declared abstract and has to be implemented
by concrete Collection
implementations.
Collection
contains, or Integer.MAX_VALUE
if there are more than Integer.MAX_VALUE
elements in this
Collection
.
Returns an array containing all elements contained in this Collection
. If
the specified array is large enough to hold the elements, the specified
array is used, otherwise an array of the same type is created. If the
specified array is used and is larger than this Collection
, the array
element following the Collection
elements is set to null.
If the implementation has ordered elements it will return the element
array in the same order as an iterator would return them.
toArray(new Object[0])
behaves exactly the same way as
toArray()
does.
contents | the array. |
---|
Collection
.Returns a new array containing all elements contained in this Collection
.
If the implementation has ordered elements it will return the element
array in the same order as an iterator would return them.
The array returned does not reflect any changes of the Collection
. A new
array is created even if the underlying data structure is already an
array.
Collection
.
Returns the string representation of this Collection
. The presentation
has a specific format. It is enclosed by square brackets ("[]"). Elements
are separated by ', ' (comma and space).
Collection
.