|
FlexDoc/Javadoc 2.0 Demo Java Doc |
Class AbstractList<E>
java.util.AbstractList<E>
All Implemented Interfaces:
Direct Known Subclasses:
public abstract class AbstractList<E>
This class provides a skeletal implementation of the
List
interface to minimize the effort required to implement this interface
backed by a "random access" data store (such as an array). For sequential
access data (such as a linked list),
AbstractSequentialList should
be used in preference to this class.
To implement an unmodifiable list, the programmer needs only to extend
this class and provide implementations for the get(int) and
size() methods.
To implement a modifiable list, the programmer must additionally
override the set(int, E) method (which otherwise
throws an UnsupportedOperationException). If the list is
variable-size the programmer must additionally override the
add(int, E) and remove(int) methods.
The programmer should generally provide a void (no argument) and collection
constructor, as per the recommendation in the Collection interface
specification.
Unlike the other abstract collection implementations, the programmer does
not have to provide an iterator implementation; the iterator and
list iterator are implemented by this class, on top of the "random access"
methods:
get(int),
set(int, E),
add(int, E) and
remove(int).
The documentation for each non-abstract method in this class describes its
implementation in detail. Each of these methods may be overridden if the
collection being implemented admits a more efficient implementation.
This class is a member of the
Java Collections Framework.
Since:
1.2
Author:
Josh Bloch, Neal Gafter
Field Summary |
protected int |
The number of times this list has been structurally modified.
|
Constructor Summary |
protected |
Sole constructor.
|
Method Summary |
boolean |
Appends the specified element to the end of this list (optional
operation).
|
void |
add(int index, E element)
Inserts the specified element at the specified position in this list
(optional operation).
|
boolean |
Inserts all of the elements in the specified collection into this
list at the specified position (optional operation).
|
void |
Removes all of the elements from this list (optional operation).
|
boolean |
Compares the specified object with this list for equality.
|
|
Returns the element at the specified position in this list.
|
int |
Returns the hash code value for this list.
|
int |
Returns the index of the first occurrence of the specified element
in this list, or -1 if this list does not contain the element.
|
|
Returns an iterator over the elements in this list in proper sequence.
|
int |
Returns the index of the last occurrence of the specified element
in this list, or -1 if this list does not contain the element.
|
|
Returns a list iterator over the elements in this list (in proper
sequence).
|
|
Returns a list iterator over the elements in this list (in proper
sequence), starting at the specified position in the list.
|
|
Removes the element at the specified position in this list (optional
operation).
|
protected void |
Removes from this list all of the elements whose index is between
fromIndex, inclusive, and toIndex, exclusive.
|
|
set(int index, E element)
Replaces the element at the specified position in this list with the
specified element (optional operation).
|
|
subList(int fromIndex, int toIndex)
Returns a view of the portion of this list between the specified
fromIndex, inclusive, and toIndex, exclusive.
|
|
addAll, contains, containsAll, isEmpty, remove, removeAll, retainAll, size, toArray, toArray, toString |
Methods inherited from class java.lang. Object |
|
Methods inherited from interface java.util. Collection |
|
Methods inherited from interface java.lang. Iterable |
|
Methods inherited from interface java.util. List |
copyOf, of, of, of, of, of, of, of, of, of, of, of, of, replaceAll, sort |
protected transient int modCount
The number of times this list has been
structurally modified.
Structural modifications are those that change the size of the
list, or otherwise perturb it in such a fashion that iterations in
progress may yield incorrect results.
This field is used by the iterator and list iterator implementation
returned by the iterator and listIterator methods.
If the value of this field changes unexpectedly, the iterator (or list
iterator) will throw a ConcurrentModificationException in
response to the next, remove, previous,
set or add operations. This provides
fail-fast behavior, rather than non-deterministic behavior in
the face of concurrent modification during iteration.
Use of this field by subclasses is optional. If a subclass
wishes to provide fail-fast iterators (and list iterators), then it
merely has to increment this field in its add(int, E) and
remove(int) methods (and any other methods that it overrides
that result in structural modifications to the list). A single call to
add(int, E) or remove(int) must add no more than
one to this field, or the iterators (and list iterators) will throw
bogus ConcurrentModificationExceptions. If an implementation
does not wish to provide fail-fast iterators, this field may be
ignored.
protected AbstractList |
() |
Sole constructor. (For invocation by subclass constructors, typically
implicit.)
Appends the specified element to the end of this list (optional
operation).
Lists that support this operation may place limitations on what
elements may be added to this list. In particular, some
lists will refuse to add null elements, and others will impose
restrictions on the type of elements that may be added. List
classes should clearly specify in their documentation any restrictions
on what elements may be added.
Implementation Requirements:
This implementation calls
add(size(), e).
Note that this implementation throws an
UnsupportedOperationException unless
add(int, E) is overridden.
Specified by:
Overrides:
Parameters:
e - element to be appended to this list
Returns:
Throws:
Returns the element at the specified position in this list.
Specified by:
Parameters:
index - index of the element to return
Returns:
the element at the specified position in this list
Throws:
Replaces the element at the specified position in this list with the
specified element (optional operation).
Implementation Requirements:
This implementation always throws an
UnsupportedOperationException.
Specified by:
Parameters:
index - index of the element to replace
element - element to be stored at the specified position
Returns:
the element previously at the specified position
Throws:
Inserts the specified element at the specified position in this list
(optional operation). Shifts the element currently at that position
(if any) and any subsequent elements to the right (adds one to their
indices).
Implementation Requirements:
This implementation always throws an
UnsupportedOperationException.
Specified by:
Parameters:
index - index at which the specified element is to be inserted
element - element to be inserted
Throws:
Removes the element at the specified position in this list (optional
operation). Shifts any subsequent elements to the left (subtracts one
from their indices). Returns the element that was removed from the
list.
Implementation Requirements:
This implementation always throws an
UnsupportedOperationException.
Specified by:
Parameters:
index - the index of the element to be removed
Returns:
the element previously at the specified position
Throws:
Returns the index of the first occurrence of the specified element
in this list, or -1 if this list does not contain the element.
More formally, returns the lowest index
i such that
Objects.equals(o, get(i)),
or -1 if there is no such index.
Implementation Requirements:
This implementation first gets a list iterator (with
listIterator()). Then, it iterates over the list until the
specified element is found or the end of the list is reached.
Specified by:
Parameters:
o - element to search for
Returns:
the index of the first occurrence of the specified element in
this list, or -1 if this list does not contain the element
Throws:
Returns the index of the last occurrence of the specified element
in this list, or -1 if this list does not contain the element.
More formally, returns the highest index
i such that
Objects.equals(o, get(i)),
or -1 if there is no such index.
Implementation Requirements:
This implementation first gets a list iterator that points to the end
of the list (with listIterator(size())). Then, it iterates
backwards over the list until the specified element is found, or the
beginning of the list is reached.
Specified by:
Parameters:
o - element to search for
Returns:
the index of the last occurrence of the specified element in
this list, or -1 if this list does not contain the element
Throws:
Removes all of the elements from this list (optional operation).
The list will be empty after this call returns.
Implementation Requirements:
This implementation calls
removeRange(0, size()).
Note that this implementation throws an
UnsupportedOperationException unless remove(int
index) or removeRange(int fromIndex, int toIndex) is
overridden.
Specified by:
Overrides:
Throws:
Inserts all of the elements in the specified collection into this
list at the specified position (optional operation). Shifts the
element currently at that position (if any) and any subsequent
elements to the right (increases their indices). The new elements
will appear in this list in the order that they are returned by the
specified collection's iterator. The behavior of this operation is
undefined if the specified collection is modified while the
operation is in progress. (Note that this will occur if the specified
collection is this list, and it's nonempty.)
Implementation Requirements:
This implementation gets an iterator over the specified collection
and iterates over it, inserting the elements obtained from the
iterator into this list at the appropriate position, one at a time,
using
add(int, E).
Many implementations will override this method for efficiency.
Note that this implementation throws an
UnsupportedOperationException unless
add(int, E) is overridden.
Specified by:
Parameters:
index - index at which to insert the first element from the
specified collection
c - collection containing elements to be added to this list
Returns:
true if this list changed as a result of the call
Throws:
UnsupportedOperationException - if the
addAll operation
is not supported by this list
ClassCastException - if the class of an element of the specified
collection prevents it from being added to this list
NullPointerException - if the specified collection contains one
or more null elements and this list does not permit null
elements, or if the specified collection is null
IllegalArgumentException - if some property of an element of the
specified collection prevents it from being added to this list
Returns an iterator over the elements in this list in proper sequence.
Implementation Requirements:
This implementation returns a straightforward implementation of the
iterator interface, relying on the backing list's
size(),
get(int), and
remove(int) methods.
Note that the iterator returned by this method will throw an
UnsupportedOperationException in response to its
remove method unless the list's remove(int) method is
overridden.
This implementation can be made to throw runtime exceptions in the
face of concurrent modification, as described in the specification
for the (protected) modCount field.
Specified by:
Overrides:
Returns:
an iterator over the elements in this list in proper sequence
Returns a list iterator over the elements in this list (in proper
sequence).
Implementation Requirements:
This implementation returns listIterator(0).
Specified by:
Returns:
a list iterator over the elements in this list (in proper
sequence)
See Also:
Returns a list iterator over the elements in this list (in proper
sequence), starting at the specified position in the list.
The specified index indicates the first element that would be
returned by an initial call to
next.
An initial call to
previous would
return the element with the specified index minus one.
Implementation Requirements:
This implementation returns a straightforward implementation of the
ListIterator interface that extends the implementation of the
Iterator interface returned by the
iterator() method.
The
ListIterator implementation relies on the backing list's
get(int),
set(int, E),
add(int, E)
and
remove(int) methods.
Note that the list iterator returned by this implementation will
throw an UnsupportedOperationException in response to its
remove, set and add methods unless the
list's remove(int), set(int, E), and
add(int, E) methods are overridden.
This implementation can be made to throw runtime exceptions in the
face of concurrent modification, as described in the specification for
the (protected) modCount field.
Specified by:
Parameters:
index - index of the first element to be returned from the
list iterator (by a call to
next)
Returns:
a list iterator over the elements in this list (in proper
sequence), starting at the specified position in the list
Throws:
|
(int fromIndex, int toIndex) |
Returns a view of the portion of this list between the specified
fromIndex, inclusive, and
toIndex, exclusive. (If
fromIndex and
toIndex are equal, the returned list is
empty.) The returned list is backed by this list, so non-structural
changes in the returned list are reflected in this list, and vice-versa.
The returned list supports all of the optional list operations supported
by this list.
This method eliminates the need for explicit range operations (of
the sort that commonly exist for arrays). Any operation that expects
a list can be used as a range operation by passing a subList view
instead of a whole list. For example, the following idiom
removes a range of elements from a list:
list.subList(from, to).clear();
Similar idioms may be constructed for
indexOf and
lastIndexOf, and all of the algorithms in the
Collections class can be applied to a subList.
The semantics of the list returned by this method become undefined if
the backing list (i.e., this list) is structurally modified in
any way other than via the returned list. (Structural modifications are
those that change the size of this list, or otherwise perturb it in such
a fashion that iterations in progress may yield incorrect results.)
Implementation Requirements:
This implementation returns a list that subclasses
AbstractList. The subclass stores, in private fields, the
size of the subList (which can change over its lifetime), and the
expected
modCount value of the backing list. There are two
variants of the subclass, one of which implements
RandomAccess.
If this list implements
RandomAccess the returned list will
be an instance of the subclass that implements
RandomAccess.
The subclass's set(int, E), get(int),
add(int, E), remove(int), addAll(int,
Collection) and removeRange(int, int) methods all
delegate to the corresponding methods on the backing abstract list,
after bounds-checking the index and adjusting for the offset. The
addAll(Collection c) method merely returns addAll(size,
c).
The listIterator(int) method returns a "wrapper object"
over a list iterator on the backing list, which is created with the
corresponding method on the backing list. The iterator method
merely returns listIterator(), and the size method
merely returns the subclass's size field.
All methods first check to see if the actual modCount of
the backing list is equal to its expected value, and throw a
ConcurrentModificationException if it is not.
Specified by:
Parameters:
fromIndex - low endpoint (inclusive) of the subList
toIndex - high endpoint (exclusive) of the subList
Returns:
a view of the specified range within this list
Throws:
Compares the specified object with this list for equality. Returns
true if and only if the specified object is also a list, both
lists have the same size, and all corresponding pairs of elements in
the two lists are
equal. (Two elements
e1 and
e2 are
equal if
(e1==null ? e2==null :
e1.equals(e2)).) In other words, two lists are defined to be
equal if they contain the same elements in the same order.
Implementation Requirements:
This implementation first checks if the specified object is this
list. If so, it returns true; if not, it checks if the
specified object is a list. If not, it returns false; if so,
it iterates over both lists, comparing corresponding pairs of elements.
If any comparison returns false, this method returns
false. If either iterator runs out of elements before the
other it returns false (as the lists are of unequal length);
otherwise it returns true when the iterations complete.
Specified by:
Overrides:
Parameters:
o - the object to be compared for equality with this list
Returns:
true if the specified object is equal to this list
See Also:
Returns the hash code value for this list.
Implementation Requirements:
This implementation uses exactly the code that is used to define the
list hash function in the documentation for the
List.hashCode()
method.
Specified by:
Overrides:
Returns:
the hash code value for this list
See Also:
protected void removeRange |
(int fromIndex, int toIndex) |
Removes from this list all of the elements whose index is between
fromIndex, inclusive, and
toIndex, exclusive.
Shifts any succeeding elements to the left (reduces their index).
This call shortens the list by
(toIndex - fromIndex) elements.
(If
toIndex==fromIndex, this operation has no effect.)
This method is called by the clear operation on this list
and its subLists. Overriding this method to take advantage of
the internals of the list implementation can substantially
improve the performance of the clear operation on this list
and its subLists.
Implementation Requirements:
This implementation gets a list iterator positioned before
fromIndex, and repeatedly calls ListIterator.next
followed by ListIterator.remove until the entire range has
been removed. Note: if ListIterator.remove requires linear
time, this implementation requires quadratic time.
Parameters:
fromIndex - index of first element to be removed
toIndex - index after last element to be removed
|
FlexDoc/Javadoc 2.0 Demo Java Doc |
FlexDoc/Javadoc is a template-driven programming tool for rapid development of any Javadoc-based Java API documentation generators (i.e. doclets). If you need to customize your Javadoc without writing a full-blown doclet from scratch,
FlexDoc/Javadoc may be the only tool able to help you! Find out more at
www.flexdoc.xyz