FileDocCategorySizeDatePackage
AbstractSequentialList.javaAPI DocJava SE 5 API10948Fri Aug 26 14:57:22 BST 2005java.util

AbstractSequentialList

public abstract class AbstractSequentialList extends AbstractList
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, Object element), set(int index, Object element), add(int index, Object 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.

author
Josh Bloch
author
Neal Gafter
version
1.33, 02/19/04
see
Collection
see
List
see
AbstractList
see
AbstractCollection
since
1.2

Fields Summary
Constructors Summary
protected AbstractSequentialList()
Sole constructor. (For invocation by subclass constructors, typically implicit.)
Methods Summary
public voidadd(int index, E element)
Inserts the specified element at the specified position in this list. 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 list iterator does not implement the add operation.

param
index index at which the specified element is to be inserted.
param
element element to be inserted.
throws
UnsupportedOperationException if the add operation is not supported by this list.
throws
NullPointerException this list does not permit null elements and one of the elements of c is null.
throws
ClassCastException if the class of the specified element prevents it from being added to this list.
throws
IllegalArgumentException if some aspect of the specified element prevents it from being added to this list.
throws
IndexOutOfBoundsException if the specified index is out of range (index < 0 || index > size()).

	ListIterator<E> e = listIterator(index);
	e.add(element);
public booleanaddAll(int index, java.util.Collection c)
Inserts all of the elements in the specified collection into this list at the specified position. 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 the list in the order that they are returned by the specified collection's iterator. The behavior of this operation is unspecified 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.) Optional operation.

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.

return
true if this list changed as a result of the call.
param
index index at which to insert first element from the specified collection.
param
c elements to be inserted into this list.
throws
UnsupportedOperationException if the addAll operation is not supported by this list.
throws
NullPointerException this list does not permit null elements and one of the elements of the specified collection is null.
throws
ClassCastException if the class of the specified element prevents it from being added to this list.
throws
IllegalArgumentException if some aspect of the specified element prevents it from being added to this list.
throws
IndexOutOfBoundsException if the specified index is out of range (index < 0 || index > size()).
throws
NullPointerException if the specified collection is null.

	boolean modified = false;
	ListIterator<E> e1 = listIterator(index);
	Iterator<? extends E> e2 = c.iterator();
	while (e2.hasNext()) {
	    e1.add(e2.next());
	    modified = true;
	}
	return modified;
public Eget(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.

param
index index of element to return.
return
the element at the specified position in this list.
throws
IndexOutOfBoundsException if the specified index is out of range (index < 0 || index >= size()).

	ListIterator<E> e = listIterator(index);
	try {
	    return(e.next());
	} catch(NoSuchElementException exc) {
	    throw(new IndexOutOfBoundsException("Index: "+index));
	}
public java.util.Iteratoriterator()
Returns an iterator over the elements in this list (in proper sequence).

This implementation merely returns a list iterator over the list.

return
an iterator over the elements in this list (in proper sequence).

        return listIterator();
public abstract java.util.ListIteratorlistIterator(int index)
Returns a list iterator over the elements in this list (in proper sequence).

param
index index of first element to be returned from the list iterator (by a call to the next method)
return
a list iterator over the elements in this list (in proper sequence).

public Eremove(int index)
Removes the element at the specified position in this list. Shifts any
subsequent elements to the left (subtracts one from their indices).


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 list iterator does not
implement the remove operation.
param
index index of the element to be removed from the List.
return
the element that was removed from the list.
throws
UnsupportedOperationException if the remove operation
is not supported by this list.
throws
IndexOutOfBoundsException if the specified index is out of
range (index < 0 || index >= size()).
	ListIterator<E> e = listIterator(index);
	E outCast;
	try {
	    outCast = e.next();
	} catch(NoSuchElementException exc) {
	    throw(new IndexOutOfBoundsException("Index: "+index));
	}
	e.remove();
	return(outCast);
    
public Eset(int index, E element)
Replaces the element at the specified position in this list with the
specified element. 


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 list iterator does not implement
the set operation.
param
index index of element to replace.
param
element element to be stored at the specified position.
return
the element previously at the specified position.
throws
UnsupportedOperationException set is not supported
by this list.
throws
NullPointerException this list does not permit null
elements and one of the elements of c is null.
throws
ClassCastException class of the specified element
prevents it from being added to this list.
throws
IllegalArgumentException some aspect of the specified
element prevents it from being added to this list.
throws
IndexOutOfBoundsException index out of range
(index < 0 || index >= size()).
throws
IllegalArgumentException fromIndex > toIndex.
	ListIterator<E> e = listIterator(index);
	try {
	    E oldVal = e.next();
	    e.set(element);
	    return oldVal;
	} catch(NoSuchElementException exc) {
	    throw(new IndexOutOfBoundsException("Index: "+index));
	}