Class AbstractSequentialList<E>
- java.lang.Object
-
- java.util.AbstractCollection<E>
-
- java.util.AbstractList<E>
-
- java.util.AbstractSequentialList<E>
- All Implemented Interfaces:
-
Iterable<E>
,Collection<E>
,List<E>
- Direct Known Subclasses:
LinkedList
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.
- Since:
- 1.2
- See Also:
-
Collection
,List
,AbstractList
,AbstractCollection
Field Summary
Fields declared in class java.util.AbstractList
modCount
Constructor Summary
Modifier | Constructor | Description |
---|---|---|
protected | AbstractSequentialList() | Sole constructor. |
Method Summary
Modifier and Type | Method | Description |
---|---|---|
void | add(int index,
E element) | Inserts the specified element at the specified position in this list (optional operation). |
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). |
E | get(int index) | Returns the element at the specified position in this list. |
Iterator<E> | iterator() | Returns an iterator over the elements in this list (in proper sequence). |
abstract ListIterator<E> | listIterator(int index) | Returns a list iterator over the elements in this list (in proper sequence). |
E | remove(int index) | Removes the element at the specified position in this list (optional operation). |
E | set(int index,
E element) | Replaces the element at the specified position in this list with the specified element (optional operation). |
Methods declared in class java.util.AbstractList
add, clear, equals, hashCode, indexOf, lastIndexOf, listIterator, removeRange, subList
Methods declared in class java.util.AbstractCollection
addAll, contains, containsAll, isEmpty, remove, removeAll, retainAll, toArray, toArray, toString
Methods declared in class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
Methods declared in interface java.util.Collection
parallelStream, removeIf, stream, toArray
Methods declared in interface java.lang.Iterable
forEach
Methods declared in interface java.util.List
addAll, contains, containsAll, isEmpty, remove, removeAll, replaceAll, retainAll, size, sort, spliterator, toArray, toArray
Constructor Detail
AbstractSequentialList
protected AbstractSequentialList()
Sole constructor. (For invocation by subclass constructors, typically implicit.)
Method Detail
get
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.
- Specified by:
-
get
in interfaceList<E>
- Specified by:
-
get
in classAbstractList<E>
- Parameters:
-
index
- index of the element to return - Returns:
- the element at the specified position in this list
- Throws:
-
IndexOutOfBoundsException
- if the index is out of range (index < 0 || index >= size()
)
set
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.
- Specified by:
-
set
in interfaceList<E>
- Overrides:
-
set
in classAbstractList<E>
- 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:
-
UnsupportedOperationException
- if theset
operation is not supported by this list -
ClassCastException
- if the class of the specified element prevents it from being added to this list -
NullPointerException
- if the specified element is null and this list does not permit null elements -
IllegalArgumentException
- if some property of the specified element prevents it from being added to this list -
IndexOutOfBoundsException
- if the index is out of range (index < 0 || index >= size()
)
add
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.
- Specified by:
-
add
in interfaceList<E>
- Overrides:
-
add
in classAbstractList<E>
- Parameters:
-
index
- index at which the specified element is to be inserted -
element
- element to be inserted - Throws:
-
UnsupportedOperationException
- if theadd
operation is not supported by this list -
ClassCastException
- if the class of the specified element prevents it from being added to this list -
NullPointerException
- if the specified element is null and this list does not permit null elements -
IllegalArgumentException
- if some property of the specified element prevents it from being added to this list -
IndexOutOfBoundsException
- if the index is out of range (index < 0 || index > size()
)
remove
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.
- Specified by:
-
remove
in interfaceList<E>
- Overrides:
-
remove
in classAbstractList<E>
- Parameters:
-
index
- the index of the element to be removed - Returns:
- the element previously at the specified position
- Throws:
-
UnsupportedOperationException
- if theremove
operation is not supported by this list -
IndexOutOfBoundsException
- if the index is out of range (index < 0 || index >= size()
)
addAll
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.
- Specified by:
-
addAll
in interfaceList<E>
- Overrides:
-
addAll
in classAbstractList<E>
- 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 theaddAll
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 -
IndexOutOfBoundsException
- if the index is out of range (index < 0 || index > size()
)
iterator
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.
- Specified by:
-
iterator
in interfaceCollection<E>
- Specified by:
-
iterator
in interfaceIterable<E>
- Specified by:
-
iterator
in interfaceList<E>
- Overrides:
-
iterator
in classAbstractList<E>
- Returns:
- an iterator over the elements in this list (in proper sequence)
listIterator
public abstract ListIterator<E> listIterator(int index)
Returns a list iterator over the elements in this list (in proper sequence).
- Specified by:
-
listIterator
in interfaceList<E>
- Overrides:
-
listIterator
in classAbstractList<E>
- Parameters:
-
index
- index of first element to be returned from the list iterator (by a call to thenext
method) - Returns:
- a list iterator over the elements in this list (in proper sequence)
- Throws:
-
IndexOutOfBoundsException
- if the index is out of range (index < 0 || index > size()
)