| /* 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; |
| |
| import java.util.Stack; |
| |
| /** |
| * 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 |
| { |
| /** |
| * Uses to track the iteration on the stack. |
| */ |
| private class ElementRef |
| { |
| /** |
| * The element. |
| */ |
| Element element; |
| |
| /** |
| * The child index. -1 means the element itself. >= 0 values mean the |
| * n-th child of the element. |
| */ |
| int index; |
| |
| /** |
| * Creates a new ElementRef. |
| * |
| * @param el the element |
| */ |
| ElementRef(Element el) |
| { |
| element = el; |
| index = -1; |
| } |
| } |
| |
| // The root element. |
| private Element root; |
| |
| /** |
| * Holds ElementRefs. |
| */ |
| private Stack stack; |
| |
| /** |
| * Create a new ElementIterator to iterate over the given document. |
| * @param document the Document over which we iterate |
| */ |
| public ElementIterator(Document document) |
| { |
| root = document.getDefaultRootElement(); |
| } |
| |
| /** |
| * 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; |
| } |
| |
| /** |
| * 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() |
| { |
| Element current; |
| if (stack == null) |
| current = first(); |
| else |
| { |
| current = null; |
| if (! stack.isEmpty()) |
| { |
| ElementRef ref = (ElementRef) stack.peek(); |
| Element el = ref.element; |
| int index = ref.index; |
| if (index == -1) |
| current = el; |
| else |
| current = el.getElement(index); |
| } |
| } |
| return current; |
| } |
| |
| /** |
| * Returns the depth to which we have descended in the tree. |
| */ |
| public int depth() |
| { |
| int depth = 0; |
| if (stack != null) |
| depth = stack.size(); |
| return depth; |
| } |
| |
| /** |
| * Returns the first element in the tree. |
| */ |
| public Element first() |
| { |
| Element first = null; |
| if (root != null) |
| { |
| stack = new Stack(); |
| if (root.getElementCount() > 0) |
| stack.push(new ElementRef(root)); |
| first = root; |
| } |
| return first; |
| } |
| |
| /** |
| * Advance the iterator and return the next element of the tree, |
| * performing an "in-order" traversal. |
| */ |
| public Element next() |
| { |
| Element next; |
| if (stack == null) |
| next = first(); |
| else |
| { |
| next = null; |
| if (! stack.isEmpty()) |
| { |
| ElementRef ref = (ElementRef) stack.peek(); |
| Element el = ref.element; |
| int index = ref.index; |
| if (el.getElementCount() > index + 1) |
| { |
| Element child = el.getElement(index + 1); |
| if (child.isLeaf()) |
| ref.index++; |
| else |
| stack.push(new ElementRef(child)); |
| next = child; |
| next = child; |
| } |
| else |
| { |
| stack.pop(); |
| if (! stack.isEmpty()) |
| { |
| ElementRef top = (ElementRef) stack.peek(); |
| top.index++; |
| next = next(); |
| } |
| } |
| } |
| // else return null. |
| } |
| return next; |
| } |
| |
| /** |
| * Returns the previous item. Does not modify the iterator state. |
| */ |
| public Element previous() |
| { |
| Element previous = null; |
| int stackSize; |
| if (stack != null && (stackSize = stack.size()) > 0) |
| { |
| ElementRef ref = (ElementRef) stack.peek(); |
| Element el = ref.element; |
| int index = ref.index; |
| if (index > 0) |
| { |
| previous = deepestLeaf(el.getElement(--index)); |
| } |
| else if (index == 0) |
| { |
| previous = el; |
| } |
| else if (index == -1) |
| { |
| ElementRef top = (ElementRef) stack.pop(); |
| ElementRef item = (ElementRef) stack.peek(); |
| stack.push(top); |
| index = item.index; |
| el = item.element; |
| previous = index == -1 ? el : deepestLeaf(el.getElement(index)); |
| } |
| } |
| return previous; |
| } |
| |
| /** |
| * Determines and returns the deepest leaf of the element <code>el</code>. |
| * |
| * @param el the base element |
| * |
| * @returnthe deepest leaf of the element <code>el</code> |
| */ |
| private Element deepestLeaf(Element el) |
| { |
| Element leaf; |
| if (el.isLeaf()) |
| leaf = el; |
| else |
| { |
| int count = el.getElementCount(); |
| if (count == 0) |
| leaf = el; |
| else |
| leaf = deepestLeaf(el.getElement(count - 1)); |
| } |
| return leaf; |
| } |
| } |