| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| /* |
| * $Id: DTMAxisTraverser.java 468653 2006-10-28 07:07:05Z minchau $ |
| */ |
| package org.apache.xml.dtm; |
| |
| /** |
| * A class that implements traverses DTMAxisTraverser interface can traverse |
| * a set of nodes, usually as defined by an XPath axis. It is different from |
| * an iterator, because it does not need to hold state, and, in fact, must not |
| * hold any iteration-based state. It is meant to be implemented as an inner |
| * class of a DTM, and returned by the getAxisTraverser(final int axis) |
| * function. |
| * |
| * <p>A DTMAxisTraverser can probably not traverse a reverse axis in |
| * document order.</p> |
| * |
| * <p>Typical usage:</p> |
| * <pre><code> |
| * for(int nodeHandle=myTraverser.first(myContext); |
| * nodeHandle!=DTM.NULL; |
| * nodeHandle=myTraverser.next(myContext,nodeHandle)) |
| * { ... processing for node indicated by nodeHandle goes here ... } |
| * </code></pre> |
| * |
| * @author Scott Boag |
| */ |
| public abstract class DTMAxisTraverser |
| { |
| |
| /** |
| * By the nature of the stateless traversal, the context node can not be |
| * returned or the iteration will go into an infinate loop. So to traverse |
| * an axis, the first function must be used to get the first node. |
| * |
| * <p>This method needs to be overloaded only by those axis that process |
| * the self node. <\p> |
| * |
| * @param context The context node of this traversal. This is the point |
| * that the traversal starts from. |
| * @return the first node in the traversal. |
| */ |
| public int first(int context) |
| { |
| return next(context, context); |
| } |
| |
| /** |
| * By the nature of the stateless traversal, the context node can not be |
| * returned or the iteration will go into an infinate loop. So to traverse |
| * an axis, the first function must be used to get the first node. |
| * |
| * <p>This method needs to be overloaded only by those axis that process |
| * the self node. <\p> |
| * |
| * @param context The context node of this traversal. This is the point |
| * of origin for the traversal -- its "root node" or starting point. |
| * @param extendedTypeID The extended type ID that must match. |
| * |
| * @return the first node in the traversal. |
| */ |
| public int first(int context, int extendedTypeID) |
| { |
| return next(context, context, extendedTypeID); |
| } |
| |
| /** |
| * Traverse to the next node after the current node. |
| * |
| * @param context The context node of this traversal. This is the point |
| * of origin for the traversal -- its "root node" or starting point. |
| * @param current The current node of the traversal. This is the last known |
| * location in the traversal, typically the node-handle returned by the |
| * previous traversal step. For the first traversal step, context |
| * should be set equal to current. Note that in order to test whether |
| * context is in the set, you must use the first() method instead. |
| * |
| * @return the next node in the iteration, or DTM.NULL. |
| * @see #first(int) |
| */ |
| public abstract int next(int context, int current); |
| |
| /** |
| * Traverse to the next node after the current node that is matched |
| * by the extended type ID. |
| * |
| * @param context The context node of this traversal. This is the point |
| * of origin for the traversal -- its "root node" or starting point. |
| * @param current The current node of the traversal. This is the last known |
| * location in the traversal, typically the node-handle returned by the |
| * previous traversal step. For the first traversal step, context |
| * should be set equal to current. Note that in order to test whether |
| * context is in the set, you must use the first() method instead. |
| * @param extendedTypeID The extended type ID that must match. |
| * |
| * @return the next node in the iteration, or DTM.NULL. |
| * @see #first(int,int) |
| */ |
| public abstract int next(int context, int current, int extendedTypeID); |
| } |