/*
* 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: CountersTable.java 468645 2006-10-28 06:57:24Z minchau $
*/
package org.apache.xalan.transformer;
import java.util.Hashtable;
import java.util.Vector;
import javax.xml.transform.TransformerException;
import org.apache.xalan.templates.ElemNumber;
import org.apache.xml.dtm.DTM;
import org.apache.xpath.NodeSetDTM;
import org.apache.xpath.XPathContext;
/**
* This is a table of counters, keyed by ElemNumber objects, each
* of which has a list of Counter objects. This really isn't a true
* table, it is more like a list of lists (there must be a technical
* term for that...).
* @xsl.usage internal
*/
public class CountersTable extends Hashtable
{
static final long serialVersionUID = 2159100770924179875L;
/**
* Construct a CountersTable.
*/
public CountersTable(){}
/**
* Get the list of counters that corresponds to
* the given ElemNumber object.
*
* @param numberElem the given xsl:number element.
*
* @return the list of counters that corresponds to
* the given ElemNumber object.
*/
Vector getCounters(ElemNumber numberElem)
{
Vector counters = (Vector) this.get(numberElem);
return (null == counters) ? putElemNumber(numberElem) : counters;
}
/**
* Put a counter into the table and create an empty
* vector as it's value.
*
* @param numberElem the given xsl:number element.
*
* @return an empty vector to be used to store counts
* for this number element.
*/
Vector putElemNumber(ElemNumber numberElem)
{
Vector counters = new Vector();
this.put(numberElem, counters);
return counters;
}
/**
* Place to collect new counters.
*/
transient private NodeSetDTM m_newFound;
/**
* Add a list of counted nodes that were built in backwards document
* order, or a list of counted nodes that are in forwards document
* order.
*
* @param flist Vector of nodes built in forwards document order
* @param blist Vector of nodes built in backwards document order
*/
void appendBtoFList(NodeSetDTM flist, NodeSetDTM blist)
{
int n = blist.size();
for (int i = (n - 1); i >= 0; i--)
{
flist.addElement(blist.item(i));
}
}
// For diagnostics
/** Number of counters created so far */
transient int m_countersMade = 0;
/**
* Count forward until the given node is found, or until
* we have looked to the given amount.
*
* @param support The XPath context to use
* @param numberElem The given xsl:number element.
* @param node The node to count.
*
* @return The node count, or 0 if not found.
*
* @throws TransformerException
*/
public int countNode(XPathContext support, ElemNumber numberElem, int node)
throws TransformerException
{
int count = 0;
Vector counters = getCounters(numberElem);
int nCounters = counters.size();
// XPath countMatchPattern = numberElem.getCountMatchPattern(support, node);
// XPath fromMatchPattern = numberElem.m_fromMatchPattern;
int target = numberElem.getTargetNode(support, node);
if (DTM.NULL != target)
{
for (int i = 0; i < nCounters; i++)
{
Counter counter = (Counter) counters.elementAt(i);
count = counter.getPreviouslyCounted(support, target);
if (count > 0)
return count;
}
// In the loop below, we collect the nodes in backwards doc order, so
// we don't have to do inserts, but then we store the nodes in forwards
// document order, so we don't have to insert nodes into that list,
// so that's what the appendBtoFList stuff is all about. In cases
// of forward counting by one, this will mean a single node copy from
// the backwards list (m_newFound) to the forwards list (counter.m_countNodes).
count = 0;
if (m_newFound == null)
m_newFound = new NodeSetDTM(support.getDTMManager());
for (; DTM.NULL != target;
target = numberElem.getPreviousNode(support, target))
{
// First time in, we should not have to check for previous counts,
// since the original target node was already checked in the
// block above.
if (0 != count)
{
for (int i = 0; i < nCounters; i++)
{
Counter counter = (Counter) counters.elementAt(i);
int cacheLen = counter.m_countNodes.size();
if ((cacheLen > 0)
&& (counter.m_countNodes.elementAt(cacheLen
- 1) == target))
{
count += (cacheLen + counter.m_countNodesStartCount);
if (cacheLen > 0)
appendBtoFList(counter.m_countNodes, m_newFound);
m_newFound.removeAllElements();
return count;
}
}
}
m_newFound.addElement(target);
count++;
}
// If we got to this point, then we didn't find a counter, so make
// one and add it to the list.
Counter counter = new Counter(numberElem, new NodeSetDTM(support.getDTMManager()));
m_countersMade++; // for diagnostics
appendBtoFList(counter.m_countNodes, m_newFound);
m_newFound.removeAllElements();
counters.addElement(counter);
}
return count;
}
}