org.apache.xml.dtm.DTMAxisTraverser Maven / Gradle / Ivy
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* 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.
*
* A DTMAxisTraverser can probably not traverse a reverse axis in
* document order.
*
* Typical usage:
*
* for(int nodeHandle=myTraverser.first(myContext);
* nodeHandle!=DTM.NULL;
* nodeHandle=myTraverser.next(myContext,nodeHandle))
* { ... processing for node indicated by nodeHandle goes here ... }
*
*
* @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.
*
* 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.
*
*
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);
}