/*
* The Apache Software License, Version 1.1
*
*
* Copyright (c) 1999 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution,
* if any, must include the following acknowledgment:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowledgment may appear in the software itself,
* if and wherever such third-party acknowledgments normally appear.
*
* 4. The names "Xalan" and "Apache Software Foundation" must
* not be used to endorse or promote products derived from this
* software without prior written permission. For written
* permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache",
* nor may "Apache" appear in their name, without prior written
* permission of the Apache Software Foundation.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation and was
* originally based on software copyright (c) 1999, Lotus
* Development Corporation., http://www.lotus.com. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*/
package org.apache.xpath.axes;
import javax.xml.transform.TransformerException;
import org.apache.xpath.compiler.Compiler;
import org.apache.xpath.patterns.NodeTest;
import org.apache.xpath.objects.XObject;
import org.apache.xpath.compiler.OpCodes;
import org.apache.xpath.XPathContext;
import org.apache.xml.dtm.DTM;
import org.apache.xml.dtm.DTMIterator;
import org.apache.xml.dtm.DTMFilter;
import org.apache.xml.dtm.DTMAxisTraverser;
import org.apache.xml.dtm.Axis;
/**
* <meta name="usage" content="advanced"/>
* This class implements an optimized iterator for
* descendant, descendant-or-self, or "//foo" patterns.
* @see org.apache.xpath.axes.WalkerFactory#newLocPathIterator
*/
public class DescendantIterator extends LocPathIterator
{
/**
* Create a DescendantIterator object.
*
* @param compiler A reference to the Compiler that contains the op map.
* @param opPos The position within the op map, which contains the
* location path expression for this itterator.
*
* @throws javax.xml.transform.TransformerException
*/
DescendantIterator(Compiler compiler, int opPos, int analysis)
throws javax.xml.transform.TransformerException
{
super(compiler, opPos, analysis, false);
int ops[] = compiler.getOpMap();
int firstStepPos = compiler.getFirstChildPos(opPos);
int stepType = ops[firstStepPos];
boolean orSelf = (OpCodes.FROM_DESCENDANTS_OR_SELF == stepType);
boolean fromRoot = false;
if (OpCodes.FROM_SELF == stepType)
{
orSelf = true;
firstStepPos += 8;
}
else if(OpCodes.FROM_ROOT == stepType)
{
// %TBD% orSelf and fromRoot should be considered seperately.
fromRoot = true;
// orSelf = true;
firstStepPos += 8;
}
if(fromRoot)
{
if(orSelf)
m_axis = Axis.DESCENDANTSORSELFFROMROOT;
else
m_axis = Axis.DESCENDANTSFROMROOT;
}
else if(orSelf)
m_axis = Axis.DESCENDANTORSELF;
else
m_axis = Axis.DESCENDANT;
int whatToShow = compiler.getWhatToShow(firstStepPos);
if ((0 == (whatToShow
& (DTMFilter.SHOW_ATTRIBUTE | DTMFilter.SHOW_ELEMENT
| DTMFilter.SHOW_PROCESSING_INSTRUCTION))) ||
(whatToShow == DTMFilter.SHOW_ALL))
initNodeTest(whatToShow);
else
{
initNodeTest(whatToShow, compiler.getStepNS(firstStepPos),
compiler.getStepLocalName(firstStepPos));
}
initPredicateInfo(compiler, firstStepPos);
}
/**
* Create a DescendantIterator object.
*
* @param compiler A reference to the Compiler that contains the op map.
* @param opPos The position within the op map, which contains the
* location path expression for this itterator.
*
* @throws javax.xml.transform.TransformerException
*/
public DescendantIterator()
{
super(null);
m_axis = Axis.DESCENDANTSORSELFFROMROOT;
int whatToShow = DTMFilter.SHOW_ALL;
initNodeTest(whatToShow);
}
/**
* Get a cloned Iterator that is reset to the beginning
* of the query.
*
* @return A cloned NodeIterator set of the start of the query.
*
* @throws CloneNotSupportedException
*/
public DTMIterator cloneWithReset() throws CloneNotSupportedException
{
DescendantIterator clone = (DescendantIterator) super.cloneWithReset();
clone.resetProximityPositions();
return clone;
}
/**
* Returns the next node in the set and advances the position of the
* iterator in the set. After a NodeIterator is created, the first call
* to nextNode() returns the first node in the set.
*
* @return The next <code>Node</code> in the set being iterated over, or
* <code>null</code> if there are no more members in that set.
*
* @throws DOMException
* INVALID_STATE_ERR: Raised if this method is called after the
* <code>detach</code> method was invoked.
*/
public int nextNode()
{
// If the cache is on, and the node has already been found, then
// just return from the list.
// If the cache is on, and the node has already been found, then
// just return from the list.
if ((null != m_cachedNodes)
&& (m_next < m_cachedNodes.size()))
{
int next = m_cachedNodes.elementAt(m_next);
incrementNextPosition();
m_currentContextNode = next;
return next;
}
if (m_foundLast)
return DTM.NULL;
if(DTM.NULL == m_lastFetched)
{
resetProximityPositions();
}
int next;
org.apache.xpath.VariableStack vars;
int savedStart;
if (-1 != m_stackFrame)
{
vars = m_execContext.getVarStack();
// These three statements need to be combined into one operation.
savedStart = vars.getStackFrame();
vars.setStackFrame(m_stackFrame);
}
else
{
// Yuck. Just to shut up the compiler!
vars = null;
savedStart = 0;
}
try
{
do
{
if(0 == m_extendedTypeID)
{
next = m_lastFetched = (DTM.NULL == m_lastFetched)
? m_traverser.first(m_context)
: m_traverser.next(m_context, m_lastFetched);
}
else
{
next = m_lastFetched = (DTM.NULL == m_lastFetched)
? m_traverser.first(m_context, m_extendedTypeID)
: m_traverser.next(m_context, m_lastFetched,
m_extendedTypeID);
}
if (DTM.NULL != next)
{
if(DTMIterator.FILTER_ACCEPT == acceptNode(next))
break;
else
continue;
}
else
break;
}
while (next != DTM.NULL);
if (DTM.NULL != next)
{
if (null != m_cachedNodes)
m_cachedNodes.addElement(m_lastFetched);
m_next++;
return next;
}
else
{
m_foundLast = true;
return DTM.NULL;
}
}
finally
{
if (-1 != m_stackFrame)
{
// These two statements need to be combined into one operation.
vars.setStackFrame(savedStart);
}
}
}
/**
* Initialize the context values for this expression
* after it is cloned.
*
* @param execContext The XPath runtime context for this
* transformation.
*/
public void setRoot(int context, Object environment)
{
super.setRoot(context, environment);
m_traverser = m_cdtm.getAxisTraverser(m_axis);
String localName = getLocalName();
String namespace = getNamespace();
int what = m_whatToShow;
// System.out.println("what: ");
// NodeTest.debugWhatToShow(what);
if(DTMFilter.SHOW_ALL == what
|| localName == NodeTest.WILD
|| namespace == NodeTest.WILD)
{
m_extendedTypeID = 0;
}
else
{
int type = getNodeTypeTest(what);
m_extendedTypeID = m_cdtm.getExpandedTypeID(namespace, localName, type);
}
}
/**
* Return the first node out of the nodeset, if this expression is
* a nodeset expression. This is the default implementation for
* nodesets.
* <p>WARNING: Do not mutate this class from this function!</p>
* @param xctxt The XPath runtime context.
* @return the first node out of the nodeset, or DTM.NULL.
*/
public int asNode(XPathContext xctxt)
throws javax.xml.transform.TransformerException
{
if(getPredicateCount() > 0)
return super.asNode(xctxt);
int current = xctxt.getCurrentNode();
DTM dtm = xctxt.getDTM(current);
DTMAxisTraverser traverser = dtm.getAxisTraverser(m_axis);
String localName = getLocalName();
String namespace = getNamespace();
int what = m_whatToShow;
// System.out.println("what: ");
// NodeTest.debugWhatToShow(what);
if(DTMFilter.SHOW_ALL == what
|| localName == NodeTest.WILD
|| namespace == NodeTest.WILD)
{
return traverser.first(current);
}
else
{
int type = getNodeTypeTest(what);
int extendedType = dtm.getExpandedTypeID(namespace, localName, type);
return traverser.first(current, extendedType);
}
}
/**
* Detaches the iterator from the set which it iterated over, releasing
* any computational resources and placing the iterator in the INVALID
* state. After<code>detach</code> has been invoked, calls to
* <code>nextNode</code> or<code>previousNode</code> will raise the
* exception INVALID_STATE_ERR.
*/
public void detach()
{
m_traverser = null;
m_extendedTypeID = 0;
// Always call the superclass detach last!
super.detach();
}
/** The traverser to use to navigate over the descendants. */
transient protected DTMAxisTraverser m_traverser;
/** The axis that we are traversing. */
protected int m_axis;
/** The extended type ID, not set until setRoot. */
protected int m_extendedTypeID;
}