| /* ListIterator.java -- Extended Iterator for iterating over ordered lists |
| Copyright (C) 1998, 1999 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., 59 Temple Place, Suite 330, Boston, MA |
| 02111-1307 USA. |
| |
| As a special exception, if you link this library with other files to |
| produce an executable, this library does not by itself cause the |
| resulting executable to be covered by the GNU General Public License. |
| This exception does not however invalidate any other reasons why the |
| executable file might be covered by the GNU General Public License. */ |
| |
| |
| 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. |
| */ |
| public interface ListIterator extends Iterator |
| { |
| /** |
| * Tests whether there are elements remaining in the list in the forward |
| * direction. |
| * |
| * @return true if there is at least one more element in the list in the |
| * forward direction, that is, if the next call to next will not throw |
| * NoSuchElementException. |
| */ |
| boolean hasNext(); |
| |
| /** |
| * Tests whether there are elements remaining in the list in the reverse |
| * direction. |
| * |
| * @return true if there is at least one more element in the list in the |
| * reverse direction, that is, if the next call to previous will not throw |
| * NoSuchElementException. |
| */ |
| 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 |
| * @exception 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 |
| * @exception NoSuchElementException if there are no more elements |
| */ |
| Object previous(); |
| |
| /** |
| * Find the index of the element that would be returned by a call to next. |
| * |
| * @return the index of the element that would be returned by a call to next, |
| * or list.size() if the iterator is at the end of the list. |
| */ |
| int nextIndex(); |
| |
| /** |
| * Find the index of the element that would be returned by a call to previous. |
| * |
| * @return the index of the element that would be returned by a call to |
| * previous, or -1 if the iterator is at the beginning of the list. |
| */ |
| int previousIndex(); |
| |
| /** |
| * Insert an element into the list at the current position of the iterator. |
| * 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. This operation is optional, it |
| * may throw an UnsupportedOperationException. |
| * |
| * @param o the object to insert into the list |
| * @exception ClassCastException the object is of a type which cannot be added |
| * to this list |
| * @exception IllegalArgumentException some other aspect of the object stops |
| * it being added to this list |
| * @exception 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. This method may only be called if neither add nor remove have |
| * been called since the last call to next or previous. This operation is |
| * optional, it may throw an UnsupportedOperationException. |
| * |
| * @exception 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. |
| * @exception 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. This method may only be called if neither add nor remove have |
| * been called since the last call to next or previous. This operation is |
| * optional, it may throw an UnsupportedOperationException. |
| * |
| * @param o the object to replace the element with |
| * @exception ClassCastException the object is of a type which cannot be added |
| * to this list |
| * @exception IllegalArgumentException some other aspect of the object stops |
| * it being added to this list |
| * @exception 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. |
| * @exception UnsupportedOperationException if this ListIterator does not |
| * support the set operation. |
| */ |
| void set(Object o); |
| } |