| /* ElementIterator.java -- |
| Copyright (C) 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 javax.swing.text; |
| |
| /** |
| * This class can be used to iterate over the {@link Element} tree of |
| * a {@link Document} or an {@link Element}. This iterator performs |
| * an "in-order" traversal -- first it visits a node, then each of the |
| * node's children in order. No locking is performed during the |
| * iteration; that is up to the caller. |
| */ |
| public class ElementIterator implements Cloneable |
| { |
| // The root element. |
| private Element root; |
| // The current element. |
| private Element currentElement; |
| // The depth to which we have descended in the tree. |
| private int currentDepth; |
| |
| // This is at least as big as the current depth, and at index N |
| // contains the index of the child element we're currently |
| // examining. |
| private int[] state; |
| |
| // The previous item. |
| private Element previousItem; |
| |
| /** |
| * Create a new ElementIterator to iterate over the given document. |
| * @param document the Document over which we iterate |
| */ |
| public ElementIterator(Document document) |
| { |
| this.root = document.getDefaultRootElement(); |
| this.currentElement = root; |
| this.state = new int[5]; |
| } |
| |
| /** |
| * Create a new ElementIterator to iterate over the given document. |
| * @param root the Document over which we iterate |
| */ |
| public ElementIterator(Element root) |
| { |
| this.root = root; |
| this.currentElement = root; |
| this.state = new int[5]; |
| } |
| |
| /** |
| * Returns a new ElementIterator which is a clone of this |
| * ElementIterator. |
| */ |
| public Object clone() |
| { |
| try |
| { |
| return super.clone(); |
| } |
| catch (CloneNotSupportedException _) |
| { |
| // Can't happen. |
| return null; |
| } |
| } |
| |
| /** |
| * Returns the current element. |
| */ |
| public Element current() |
| { |
| return currentElement; |
| } |
| |
| /** |
| * Returns the depth to which we have descended in the tree. |
| */ |
| public int depth() |
| { |
| return currentDepth; |
| } |
| |
| /** |
| * Returns the first element in the tree. |
| */ |
| public Element first() |
| { |
| // Reset the iterator. |
| currentElement = root; |
| currentDepth = 0; |
| previousItem = null; |
| return root; |
| } |
| |
| /** |
| * Advance the iterator and return the next element of the tree, |
| * performing an "in-order" traversal. |
| */ |
| public Element next() |
| { |
| previousItem = currentElement; |
| if (currentElement == null) |
| return null; |
| if (! currentElement.isLeaf()) |
| { |
| ++currentDepth; |
| if (currentDepth > state.length) |
| { |
| int[] newState = new int[state.length * 2]; |
| System.arraycopy(state, 0, newState, 0, state.length); |
| state = newState; |
| } |
| state[currentDepth] = 0; |
| currentElement = currentElement.getElement(0); |
| return currentElement; |
| } |
| |
| while (currentDepth > 0) |
| { |
| // At a leaf, or done with a non-leaf's children, so go up a |
| // level. |
| --currentDepth; |
| currentElement = currentElement.getParentElement(); |
| ++state[currentDepth]; |
| if (state[currentDepth] < currentElement.getElementCount()) |
| { |
| currentElement = currentElement.getElement(state[currentDepth]); |
| return currentElement; |
| } |
| } |
| |
| currentElement = null; |
| return currentElement; |
| } |
| |
| /** |
| * Returns the previous item. Does not modify the iterator state. |
| */ |
| public Element previous() |
| { |
| if (currentElement == null || currentElement == root) |
| return null; |
| return previousItem; |
| } |
| } |