| /* ListIterator.java -- Extended Iterator for iterating over ordered lists |
| Copyright (C) 1998, 1999, 2001, 2005 Free Software Foundation, Inc. |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| GNU Classpath is distributed in the hope that it will be useful, but |
| WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
| 02110-1301 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| |
| package java.util; |
| |
| /** |
| * An extended version of Iterator to support the extra features of Lists. The |
| * elements may be accessed in forward or reverse order, elements may be |
| * replaced as well as removed, and new elements may be inserted, during the |
| * traversal of the list. |
| * <p> |
| * |
| * A list with n elements provides n+1 iterator positions (the front, the end, |
| * or between two elements). Note that <code>remove</code> and <code>set</code> |
| * operate on the last element returned, whether it was by <code>next</code> |
| * or <code>previous</code>. |
| * |
| * @author Original author unknown |
| * @author Eric Blake (ebb9@email.byu.edu) |
| * @see Collection |
| * @see List |
| * @see Iterator |
| * @see Enumeration |
| * @since 1.2 |
| * @status updated to 1.4 |
| */ |
| public interface ListIterator extends Iterator |
| { |
| /** |
| * Tests whether there are elements remaining in the list in the forward |
| * direction. In other words, next() will not fail with a |
| * NoSuchElementException. |
| * |
| * @return true if the list continues in the forward direction |
| */ |
| boolean hasNext(); |
| |
| /** |
| * Tests whether there are elements remaining in the list in the reverse |
| * direction. In other words, previous() will not fail with a |
| * NoSuchElementException. |
| * |
| * @return true if the list continues in the reverse direction |
| */ |
| boolean hasPrevious(); |
| |
| /** |
| * Obtain the next element in the list in the forward direction. Repeated |
| * calls to next may be used to iterate over the entire list, or calls to |
| * next and previous may be used together to go forwards and backwards. |
| * Alternating calls to next and previous will return the same element. |
| * |
| * @return the next element in the list in the forward direction |
| * @throws NoSuchElementException if there are no more elements |
| */ |
| Object next(); |
| |
| /** |
| * Obtain the next element in the list in the reverse direction. Repeated |
| * calls to previous may be used to iterate backwards over the entire list, |
| * or calls to next and previous may be used together to go forwards and |
| * backwards. Alternating calls to next and previous will return the same |
| * element. |
| * |
| * @return the next element in the list in the reverse direction |
| * @throws NoSuchElementException if there are no more elements |
| */ |
| Object previous(); |
| |
| /** |
| * Find the index of the element that would be returned by a call to next. |
| * If hasNext() returns false, this returns the list size. |
| * |
| * @return the index of the element that would be returned by next() |
| */ |
| int nextIndex(); |
| |
| /** |
| * Find the index of the element that would be returned by a call to |
| * previous. If hasPrevious() returns false, this returns -1. |
| * |
| * @return the index of the element that would be returned by previous() |
| */ |
| int previousIndex(); |
| |
| /** |
| * Insert an element into the list at the current position of the iterator |
| * (optional operation). The element is inserted in between the element that |
| * would be returned by previous and the element that would be returned by |
| * next. After the insertion, a subsequent call to next is unaffected, but |
| * a call to previous returns the item that was added. The values returned |
| * by nextIndex() and previousIndex() are incremented. |
| * |
| * @param o the object to insert into the list |
| * @throws ClassCastException if the object is of a type which cannot be added |
| * to this list. |
| * @throws IllegalArgumentException if some other aspect of the object stops |
| * it being added to this list. |
| * @throws UnsupportedOperationException if this ListIterator does not |
| * support the add operation. |
| */ |
| void add(Object o); |
| |
| /** |
| * Remove from the list the element last returned by a call to next or |
| * previous (optional operation). This method may only be called if neither |
| * add nor remove have been called since the last call to next or previous. |
| * |
| * @throws IllegalStateException if neither next or previous have been |
| * called, or if add or remove has been called since the last call |
| * to next or previous |
| * @throws UnsupportedOperationException if this ListIterator does not |
| * support the remove operation |
| */ |
| void remove(); |
| |
| /** |
| * Replace the element last returned by a call to next or previous with a |
| * given object (optional operation). This method may only be called if |
| * neither add nor remove have been called since the last call to next or |
| * previous. |
| * |
| * @param o the object to replace the element with |
| * @throws ClassCastException the object is of a type which cannot be added |
| * to this list |
| * @throws IllegalArgumentException some other aspect of the object stops |
| * it being added to this list |
| * @throws IllegalStateException if neither next or previous have been |
| * called, or if add or remove has been called since the last call |
| * to next or previous |
| * @throws UnsupportedOperationException if this ListIterator does not |
| * support the set operation |
| */ |
| void set(Object o); |
| } |