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AbstractSequentialList.javaAPI DocJava SE 6 API9098Tue Jun 10 00:25:52 BST 2008java.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, 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.

author
Josh Bloch
author
Neal Gafter
version
1.36, 04/21/06
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 (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.

throws
UnsupportedOperationException {@inheritDoc}
throws
ClassCastException {@inheritDoc}
throws
NullPointerException {@inheritDoc}
throws
IllegalArgumentException {@inheritDoc}
throws
IndexOutOfBoundsException {@inheritDoc}

	try {
	    listIterator(index).add(element);
	} catch (NoSuchElementException exc) {
	    throw new IndexOutOfBoundsException("Index: "+index);
	}
public booleanaddAll(int index, java.util.Collection 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.

throws
UnsupportedOperationException {@inheritDoc}
throws
ClassCastException {@inheritDoc}
throws
NullPointerException {@inheritDoc}
throws
IllegalArgumentException {@inheritDoc}
throws
IndexOutOfBoundsException {@inheritDoc}

	try {
	    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;
	} catch (NoSuchElementException exc) {
	    throw new IndexOutOfBoundsException("Index: "+index);
	}
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.

throws
IndexOutOfBoundsException {@inheritDoc}

        try {
            return listIterator(index).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)
throws
IndexOutOfBoundsException {@inheritDoc}

public Eremove(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.
throws
UnsupportedOperationException {@inheritDoc}
throws
IndexOutOfBoundsException {@inheritDoc}
	try {
	    ListIterator<E> e = listIterator(index);
	    E outCast = e.next();
	    e.remove();
	    return outCast;
	} catch (NoSuchElementException exc) {
	    throw new IndexOutOfBoundsException("Index: "+index);
	}
    
public Eset(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.
throws
UnsupportedOperationException {@inheritDoc}
throws
ClassCastException {@inheritDoc}
throws
NullPointerException {@inheritDoc}
throws
IllegalArgumentException {@inheritDoc}
throws
IndexOutOfBoundsException {@inheritDoc}
	try {
	    ListIterator<E> e = listIterator(index);
	    E oldVal = e.next();
	    e.set(element);
	    return oldVal;
	} catch (NoSuchElementException exc) {
	    throw new IndexOutOfBoundsException("Index: "+index);
	}