public abstract class AbstractSequentialList<E> extends AbstractList<E>
This class provides a skeletal implementation of the List
interface to minimize the effort required to implement this interface backed by a "sequential access" data store (such as a linked list). For random access data (such as an array), AbstractList
should be used in preference to this class.
This class is the opposite of the AbstractList
class in the sense that it implements the "random access" methods (get(int index)
, set(int index, E element)
, add(int index, E element)
and remove(int index)
) on top of the list's list iterator, instead of the other way around.
To implement a list the programmer needs only to extend this class and provide implementations for the listIterator
and size
methods. For an unmodifiable list, the programmer need only implement the list iterator's hasNext
, next
, hasPrevious
, previous
and index
methods.
For a modifiable list the programmer should additionally implement the list iterator's set
method. For a variable-size list the programmer should additionally implement the list iterator's remove
and add
methods.
The programmer should generally provide a void (no argument) and collection constructor, as per the recommendation in the Collection
interface specification.
This class is a member of the Java Collections Framework.
Collection
, List
, AbstractList
, AbstractCollection
modCount
protected AbstractSequentialList()
Sole constructor. (For invocation by subclass constructors, typically implicit.)
public E get(int index)
Returns the element at the specified position in this list.
This implementation first gets a list iterator pointing to the indexed element (with listIterator(index)
). Then, it gets the element using ListIterator.next
and returns it.
get
in interface List<E>
get
in class AbstractList<E>
index
- index of the element to returnIndexOutOfBoundsException
- if the index is out of range (index < 0 || index >= size()
)public E set(int index, E element)
Replaces the element at the specified position in this list with the specified element (optional operation).
This implementation first gets a list iterator pointing to the indexed element (with listIterator(index)
). Then, it gets the current element using ListIterator.next
and replaces it with ListIterator.set
.
Note that this implementation will throw an UnsupportedOperationException
if the list iterator does not implement the set
operation.
set
in interface List<E>
set
in class AbstractList<E>
index
- index of the element to replaceelement
- element to be stored at the specified positionUnsupportedOperationException
- if the set
operation is not supported by this listClassCastException
- if the class of the specified element prevents it from being added to this listNullPointerException
- if the specified element is null and this list does not permit null elementsIllegalArgumentException
- if some property of the specified element prevents it from being added to this listIndexOutOfBoundsException
- if the index is out of range (index < 0 || index >= size()
)public void add(int index, E element)
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).
This implementation first gets a list iterator pointing to the indexed element (with listIterator(index)
). Then, it inserts the specified element with ListIterator.add
.
Note that this implementation will throw an UnsupportedOperationException
if the list iterator does not implement the add
operation.
add
in interface List<E>
add
in class AbstractList<E>
index
- index at which the specified element is to be insertedelement
- element to be insertedUnsupportedOperationException
- if the add
operation is not supported by this listClassCastException
- if the class of the specified element prevents it from being added to this listNullPointerException
- if the specified element is null and this list does not permit null elementsIllegalArgumentException
- if some property of the specified element prevents it from being added to this listIndexOutOfBoundsException
- if the index is out of range (index < 0 || index > size()
)public E remove(int index)
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.
This implementation first gets a list iterator pointing to the indexed element (with listIterator(index)
). Then, it removes the element with ListIterator.remove
.
Note that this implementation will throw an UnsupportedOperationException
if the list iterator does not implement the remove
operation.
remove
in interface List<E>
remove
in class AbstractList<E>
index
- the index of the element to be removedUnsupportedOperationException
- if the remove
operation is not supported by this listIndexOutOfBoundsException
- if the index is out of range (index < 0 || index >= size()
)public boolean addAll(int index, Collection<? extends E> c)
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.)
This implementation gets an iterator over the specified collection and a list iterator over this list pointing to the indexed element (with listIterator(index)
). Then, it iterates over the specified collection, inserting the elements obtained from the iterator into this list, one at a time, using ListIterator.add
followed by ListIterator.next
(to skip over the added element).
Note that this implementation will throw an UnsupportedOperationException
if the list iterator returned by the listIterator
method does not implement the add
operation.
addAll
in interface List<E>
addAll
in class AbstractList<E>
index
- index at which to insert the first element from the specified collectionc
- collection containing elements to be added to this listtrue
if this list changed as a result of the callUnsupportedOperationException
- if the addAll
operation is not supported by this listClassCastException
- if the class of an element of the specified collection prevents it from being added to this listNullPointerException
- if the specified collection contains one or more null elements and this list does not permit null elements, or if the specified collection is nullIllegalArgumentException
- if some property of an element of the specified collection prevents it from being added to this listIndexOutOfBoundsException
- if the index is out of range (index < 0 || index > size()
)public Iterator<E> iterator()
Returns an iterator over the elements in this list (in proper sequence).
This implementation merely returns a list iterator over the list.
iterator
in interface Iterable<E>
iterator
in interface Collection<E>
iterator
in interface List<E>
iterator
in class AbstractList<E>
public abstract ListIterator<E> listIterator(int index)
Returns a list iterator over the elements in this list (in proper sequence).
listIterator
in interface List<E>
listIterator
in class AbstractList<E>
index
- index of first element to be returned from the list iterator (by a call to the next
method)IndexOutOfBoundsException
- if the index is out of range (index < 0 || index > size()
)
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