jaroslav@597: /*
jaroslav@597:  * Copyright (c) 1997, 2006, Oracle and/or its affiliates. All rights reserved.
jaroslav@597:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
jaroslav@597:  *
jaroslav@597:  * This code is free software; you can redistribute it and/or modify it
jaroslav@597:  * under the terms of the GNU General Public License version 2 only, as
jaroslav@597:  * published by the Free Software Foundation.  Oracle designates this
jaroslav@597:  * particular file as subject to the "Classpath" exception as provided
jaroslav@597:  * by Oracle in the LICENSE file that accompanied this code.
jaroslav@597:  *
jaroslav@597:  * This code is distributed in the hope that it will be useful, but WITHOUT
jaroslav@597:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
jaroslav@597:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
jaroslav@597:  * version 2 for more details (a copy is included in the LICENSE file that
jaroslav@597:  * accompanied this code).
jaroslav@597:  *
jaroslav@597:  * You should have received a copy of the GNU General Public License version
jaroslav@597:  * 2 along with this work; if not, write to the Free Software Foundation,
jaroslav@597:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
jaroslav@597:  *
jaroslav@597:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
jaroslav@597:  * or visit www.oracle.com if you need additional information or have any
jaroslav@597:  * questions.
jaroslav@597:  */
jaroslav@597: 
jaroslav@597: package java.util;
jaroslav@597: 
jaroslav@597: /**
jaroslav@597:  * This class provides a skeletal implementation of the <tt>List</tt>
jaroslav@597:  * interface to minimize the effort required to implement this interface
jaroslav@597:  * backed by a "sequential access" data store (such as a linked list).  For
jaroslav@597:  * random access data (such as an array), <tt>AbstractList</tt> should be used
jaroslav@597:  * in preference to this class.<p>
jaroslav@597:  *
jaroslav@597:  * This class is the opposite of the <tt>AbstractList</tt> class in the sense
jaroslav@597:  * that it implements the "random access" methods (<tt>get(int index)</tt>,
jaroslav@597:  * <tt>set(int index, E element)</tt>, <tt>add(int index, E element)</tt> and
jaroslav@597:  * <tt>remove(int index)</tt>) on top of the list's list iterator, instead of
jaroslav@597:  * the other way around.<p>
jaroslav@597:  *
jaroslav@597:  * To implement a list the programmer needs only to extend this class and
jaroslav@597:  * provide implementations for the <tt>listIterator</tt> and <tt>size</tt>
jaroslav@597:  * methods.  For an unmodifiable list, the programmer need only implement the
jaroslav@597:  * list iterator's <tt>hasNext</tt>, <tt>next</tt>, <tt>hasPrevious</tt>,
jaroslav@597:  * <tt>previous</tt> and <tt>index</tt> methods.<p>
jaroslav@597:  *
jaroslav@597:  * For a modifiable list the programmer should additionally implement the list
jaroslav@597:  * iterator's <tt>set</tt> method.  For a variable-size list the programmer
jaroslav@597:  * should additionally implement the list iterator's <tt>remove</tt> and
jaroslav@597:  * <tt>add</tt> methods.<p>
jaroslav@597:  *
jaroslav@597:  * The programmer should generally provide a void (no argument) and collection
jaroslav@597:  * constructor, as per the recommendation in the <tt>Collection</tt> interface
jaroslav@597:  * specification.<p>
jaroslav@597:  *
jaroslav@597:  * This class is a member of the
jaroslav@597:  * <a href="{@docRoot}/../technotes/guides/collections/index.html">
jaroslav@597:  * Java Collections Framework</a>.
jaroslav@597:  *
jaroslav@597:  * @author  Josh Bloch
jaroslav@597:  * @author  Neal Gafter
jaroslav@597:  * @see Collection
jaroslav@597:  * @see List
jaroslav@597:  * @see AbstractList
jaroslav@597:  * @see AbstractCollection
jaroslav@597:  * @since 1.2
jaroslav@597:  */
jaroslav@597: 
jaroslav@597: public abstract class AbstractSequentialList<E> extends AbstractList<E> {
jaroslav@597:     /**
jaroslav@597:      * Sole constructor.  (For invocation by subclass constructors, typically
jaroslav@597:      * implicit.)
jaroslav@597:      */
jaroslav@597:     protected AbstractSequentialList() {
jaroslav@597:     }
jaroslav@597: 
jaroslav@597:     /**
jaroslav@597:      * Returns the element at the specified position in this list.
jaroslav@597:      *
jaroslav@597:      * <p>This implementation first gets a list iterator pointing to the
jaroslav@597:      * indexed element (with <tt>listIterator(index)</tt>).  Then, it gets
jaroslav@597:      * the element using <tt>ListIterator.next</tt> and returns it.
jaroslav@597:      *
jaroslav@597:      * @throws IndexOutOfBoundsException {@inheritDoc}
jaroslav@597:      */
jaroslav@597:     public E get(int index) {
jaroslav@597:         try {
jaroslav@597:             return listIterator(index).next();
jaroslav@597:         } catch (NoSuchElementException exc) {
jaroslav@597:             throw new IndexOutOfBoundsException("Index: "+index);
jaroslav@597:         }
jaroslav@597:     }
jaroslav@597: 
jaroslav@597:     /**
jaroslav@597:      * Replaces the element at the specified position in this list with the
jaroslav@597:      * specified element (optional operation).
jaroslav@597:      *
jaroslav@597:      * <p>This implementation first gets a list iterator pointing to the
jaroslav@597:      * indexed element (with <tt>listIterator(index)</tt>).  Then, it gets
jaroslav@597:      * the current element using <tt>ListIterator.next</tt> and replaces it
jaroslav@597:      * with <tt>ListIterator.set</tt>.
jaroslav@597:      *
jaroslav@597:      * <p>Note that this implementation will throw an
jaroslav@597:      * <tt>UnsupportedOperationException</tt> if the list iterator does not
jaroslav@597:      * implement the <tt>set</tt> operation.
jaroslav@597:      *
jaroslav@597:      * @throws UnsupportedOperationException {@inheritDoc}
jaroslav@597:      * @throws ClassCastException            {@inheritDoc}
jaroslav@597:      * @throws NullPointerException          {@inheritDoc}
jaroslav@597:      * @throws IllegalArgumentException      {@inheritDoc}
jaroslav@597:      * @throws IndexOutOfBoundsException     {@inheritDoc}
jaroslav@597:      */
jaroslav@597:     public E set(int index, E element) {
jaroslav@597:         try {
jaroslav@597:             ListIterator<E> e = listIterator(index);
jaroslav@597:             E oldVal = e.next();
jaroslav@597:             e.set(element);
jaroslav@597:             return oldVal;
jaroslav@597:         } catch (NoSuchElementException exc) {
jaroslav@597:             throw new IndexOutOfBoundsException("Index: "+index);
jaroslav@597:         }
jaroslav@597:     }
jaroslav@597: 
jaroslav@597:     /**
jaroslav@597:      * Inserts the specified element at the specified position in this list
jaroslav@597:      * (optional operation).  Shifts the element currently at that position
jaroslav@597:      * (if any) and any subsequent elements to the right (adds one to their
jaroslav@597:      * indices).
jaroslav@597:      *
jaroslav@597:      * <p>This implementation first gets a list iterator pointing to the
jaroslav@597:      * indexed element (with <tt>listIterator(index)</tt>).  Then, it
jaroslav@597:      * inserts the specified element with <tt>ListIterator.add</tt>.
jaroslav@597:      *
jaroslav@597:      * <p>Note that this implementation will throw an
jaroslav@597:      * <tt>UnsupportedOperationException</tt> if the list iterator does not
jaroslav@597:      * implement the <tt>add</tt> operation.
jaroslav@597:      *
jaroslav@597:      * @throws UnsupportedOperationException {@inheritDoc}
jaroslav@597:      * @throws ClassCastException            {@inheritDoc}
jaroslav@597:      * @throws NullPointerException          {@inheritDoc}
jaroslav@597:      * @throws IllegalArgumentException      {@inheritDoc}
jaroslav@597:      * @throws IndexOutOfBoundsException     {@inheritDoc}
jaroslav@597:      */
jaroslav@597:     public void add(int index, E element) {
jaroslav@597:         try {
jaroslav@597:             listIterator(index).add(element);
jaroslav@597:         } catch (NoSuchElementException exc) {
jaroslav@597:             throw new IndexOutOfBoundsException("Index: "+index);
jaroslav@597:         }
jaroslav@597:     }
jaroslav@597: 
jaroslav@597:     /**
jaroslav@597:      * Removes the element at the specified position in this list (optional
jaroslav@597:      * operation).  Shifts any subsequent elements to the left (subtracts one
jaroslav@597:      * from their indices).  Returns the element that was removed from the
jaroslav@597:      * list.
jaroslav@597:      *
jaroslav@597:      * <p>This implementation first gets a list iterator pointing to the
jaroslav@597:      * indexed element (with <tt>listIterator(index)</tt>).  Then, it removes
jaroslav@597:      * the element with <tt>ListIterator.remove</tt>.
jaroslav@597:      *
jaroslav@597:      * <p>Note that this implementation will throw an
jaroslav@597:      * <tt>UnsupportedOperationException</tt> if the list iterator does not
jaroslav@597:      * implement the <tt>remove</tt> operation.
jaroslav@597:      *
jaroslav@597:      * @throws UnsupportedOperationException {@inheritDoc}
jaroslav@597:      * @throws IndexOutOfBoundsException     {@inheritDoc}
jaroslav@597:      */
jaroslav@597:     public E remove(int index) {
jaroslav@597:         try {
jaroslav@597:             ListIterator<E> e = listIterator(index);
jaroslav@597:             E outCast = e.next();
jaroslav@597:             e.remove();
jaroslav@597:             return outCast;
jaroslav@597:         } catch (NoSuchElementException exc) {
jaroslav@597:             throw new IndexOutOfBoundsException("Index: "+index);
jaroslav@597:         }
jaroslav@597:     }
jaroslav@597: 
jaroslav@597: 
jaroslav@597:     // Bulk Operations
jaroslav@597: 
jaroslav@597:     /**
jaroslav@597:      * Inserts all of the elements in the specified collection into this
jaroslav@597:      * list at the specified position (optional operation).  Shifts the
jaroslav@597:      * element currently at that position (if any) and any subsequent
jaroslav@597:      * elements to the right (increases their indices).  The new elements
jaroslav@597:      * will appear in this list in the order that they are returned by the
jaroslav@597:      * specified collection's iterator.  The behavior of this operation is
jaroslav@597:      * undefined if the specified collection is modified while the
jaroslav@597:      * operation is in progress.  (Note that this will occur if the specified
jaroslav@597:      * collection is this list, and it's nonempty.)
jaroslav@597:      *
jaroslav@597:      * <p>This implementation gets an iterator over the specified collection and
jaroslav@597:      * a list iterator over this list pointing to the indexed element (with
jaroslav@597:      * <tt>listIterator(index)</tt>).  Then, it iterates over the specified
jaroslav@597:      * collection, inserting the elements obtained from the iterator into this
jaroslav@597:      * list, one at a time, using <tt>ListIterator.add</tt> followed by
jaroslav@597:      * <tt>ListIterator.next</tt> (to skip over the added element).
jaroslav@597:      *
jaroslav@597:      * <p>Note that this implementation will throw an
jaroslav@597:      * <tt>UnsupportedOperationException</tt> if the list iterator returned by
jaroslav@597:      * the <tt>listIterator</tt> method does not implement the <tt>add</tt>
jaroslav@597:      * operation.
jaroslav@597:      *
jaroslav@597:      * @throws UnsupportedOperationException {@inheritDoc}
jaroslav@597:      * @throws ClassCastException            {@inheritDoc}
jaroslav@597:      * @throws NullPointerException          {@inheritDoc}
jaroslav@597:      * @throws IllegalArgumentException      {@inheritDoc}
jaroslav@597:      * @throws IndexOutOfBoundsException     {@inheritDoc}
jaroslav@597:      */
jaroslav@597:     public boolean addAll(int index, Collection<? extends E> c) {
jaroslav@597:         try {
jaroslav@597:             boolean modified = false;
jaroslav@597:             ListIterator<E> e1 = listIterator(index);
jaroslav@597:             Iterator<? extends E> e2 = c.iterator();
jaroslav@597:             while (e2.hasNext()) {
jaroslav@597:                 e1.add(e2.next());
jaroslav@597:                 modified = true;
jaroslav@597:             }
jaroslav@597:             return modified;
jaroslav@597:         } catch (NoSuchElementException exc) {
jaroslav@597:             throw new IndexOutOfBoundsException("Index: "+index);
jaroslav@597:         }
jaroslav@597:     }
jaroslav@597: 
jaroslav@597: 
jaroslav@597:     // Iterators
jaroslav@597: 
jaroslav@597:     /**
jaroslav@597:      * Returns an iterator over the elements in this list (in proper
jaroslav@597:      * sequence).<p>
jaroslav@597:      *
jaroslav@597:      * This implementation merely returns a list iterator over the list.
jaroslav@597:      *
jaroslav@597:      * @return an iterator over the elements in this list (in proper sequence)
jaroslav@597:      */
jaroslav@597:     public Iterator<E> iterator() {
jaroslav@597:         return listIterator();
jaroslav@597:     }
jaroslav@597: 
jaroslav@597:     /**
jaroslav@597:      * Returns a list iterator over the elements in this list (in proper
jaroslav@597:      * sequence).
jaroslav@597:      *
jaroslav@597:      * @param  index index of first element to be returned from the list
jaroslav@597:      *         iterator (by a call to the <code>next</code> method)
jaroslav@597:      * @return a list iterator over the elements in this list (in proper
jaroslav@597:      *         sequence)
jaroslav@597:      * @throws IndexOutOfBoundsException {@inheritDoc}
jaroslav@597:      */
jaroslav@597:     public abstract ListIterator<E> listIterator(int index);
jaroslav@597: }