/*
* Copyright 1999-2004 The Apache Software Foundation.
*
* Licensed 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: KeyTable.java,v 1.19 2005/01/23 00:37:17 mcnamara Exp $
*/
package org.apache.xalan.transformer;
import java.util.Hashtable;
import java.util.Vector;
import javax.xml.transform.TransformerException;
import org.apache.xalan.templates.KeyDeclaration;
import org.apache.xml.dtm.DTM;
import org.apache.xml.dtm.DTMIterator;
import org.apache.xml.utils.PrefixResolver;
import org.apache.xml.utils.QName;
import org.apache.xml.utils.WrappedRuntimeException;
import org.apache.xml.utils.XMLString;
import org.apache.xpath.XPathContext;
import org.apache.xpath.objects.XNodeSet;
import org.apache.xpath.objects.XObject;
/**
* Table of element keys, keyed by document node. An instance of this
* class is keyed by a Document node that should be matched with the
* root of the current context.
* @xsl.usage advanced
*/
public class KeyTable
{
/**
* The document key. This table should only be used with contexts
* whose Document roots match this key.
*/
private int m_docKey;
/**
* Vector of KeyDeclaration instances holding the key declarations.
*/
private Vector m_keyDeclarations;
/**
* Hold a cache of key() function result for each ref.
* Key is XMLString, the ref value
* Value is XNodeSet, the key() function result for the given ref value.
*/
private Hashtable m_refsTable = null;
/**
* Get the document root matching this key.
*
* @return the document root matching this key
*/
public int getDocKey()
{
return m_docKey;
}
/**
* The main iterator that will walk through the source
* tree for this key.
*/
private XNodeSet m_keyNodes;
KeyIterator getKeyIterator()
{
return (KeyIterator)(m_keyNodes.getContainedIter());
}
/**
* Build a keys table.
* @param doc The owner document key.
* @param nscontext The stylesheet's namespace context.
* @param name The key name
* @param keyDeclarations The stylesheet's xsl:key declarations.
*
* @throws javax.xml.transform.TransformerException
*/
public KeyTable(
int doc, PrefixResolver nscontext, QName name, Vector keyDeclarations, XPathContext xctxt)
throws javax.xml.transform.TransformerException
{
m_docKey = doc;
m_keyDeclarations = keyDeclarations;
KeyIterator ki = new KeyIterator(name, keyDeclarations);
m_keyNodes = new XNodeSet(ki);
m_keyNodes.allowDetachToRelease(false);
m_keyNodes.setRoot(doc, xctxt);
}
/**
* Given a valid element key, return the corresponding node list.
*
* @param name The name of the key, which must match the 'name' attribute on xsl:key.
* @param ref The value that must match the value found by the 'match' attribute on xsl:key.
* @return a set of nodes referenced by the key named <CODE>name</CODE> and the reference <CODE>ref</CODE>. If no node is referenced by this key, an empty node set is returned.
*/
public XNodeSet getNodeSetDTMByKey(QName name, XMLString ref)
{
XNodeSet refNodes = (XNodeSet) getRefsTable().get(ref);
// clone wiht reset the node set
try
{
if (refNodes != null)
{
refNodes = (XNodeSet) refNodes.cloneWithReset();
}
}
catch (CloneNotSupportedException e)
{
refNodes = null;
}
if (refNodes == null) {
// create an empty XNodeSet
KeyIterator ki = (KeyIterator) (m_keyNodes).getContainedIter();
XPathContext xctxt = ki.getXPathContext();
refNodes = new XNodeSet(xctxt.getDTMManager()) {
public void setRoot(int nodeHandle, Object environment) {
// Root cannot be set on non-iterated node sets. Ignore it.
}
};
refNodes.reset();
}
return refNodes;
}
/**
* Get Key Name for this KeyTable
*
* @return Key name
*/
public QName getKeyTableName()
{
return getKeyIterator().getName();
}
/**
* @return key declarations for the key associated to this KeyTable
*/
private Vector getKeyDeclarations() {
int nDeclarations = m_keyDeclarations.size();
Vector keyDecls = new Vector(nDeclarations);
// Walk through each of the declarations made with xsl:key
for (int i = 0; i < nDeclarations; i++)
{
KeyDeclaration kd = (KeyDeclaration) m_keyDeclarations.elementAt(i);
// Add the declaration if the name on this key declaration
// matches the name on the iterator for this walker.
if (kd.getName().equals(getKeyTableName())) {
keyDecls.add(kd);
}
}
return keyDecls;
}
/**
* @return lazy initialized refs table associating evaluation of key function
* with a XNodeSet
*/
private Hashtable getRefsTable()
{
if (m_refsTable == null) {
// initial capacity set to a prime number to improve hash performance
m_refsTable = new Hashtable(89);
KeyIterator ki = (KeyIterator) (m_keyNodes).getContainedIter();
XPathContext xctxt = ki.getXPathContext();
Vector keyDecls = getKeyDeclarations();
int nKeyDecls = keyDecls.size();
int currentNode;
m_keyNodes.reset();
while (DTM.NULL != (currentNode = m_keyNodes.nextNode()))
{
try
{
for (int keyDeclIdx = 0; keyDeclIdx < nKeyDecls; keyDeclIdx++) {
KeyDeclaration keyDeclaration =
(KeyDeclaration) keyDecls.elementAt(keyDeclIdx);
XObject xuse =
keyDeclaration.getUse().execute(xctxt,
currentNode,
ki.getPrefixResolver());
if (xuse.getType() != xuse.CLASS_NODESET) {
XMLString exprResult = xuse.xstr();
addValueInRefsTable(xctxt, exprResult, currentNode);
} else {
DTMIterator i = ((XNodeSet)xuse).iterRaw();
int currentNodeInUseClause;
while (DTM.NULL != (currentNodeInUseClause = i.nextNode())) {
DTM dtm = xctxt.getDTM(currentNodeInUseClause);
XMLString exprResult =
dtm.getStringValue(currentNodeInUseClause);
addValueInRefsTable(xctxt, exprResult, currentNode);
}
}
}
} catch (TransformerException te) {
throw new WrappedRuntimeException(te);
}
}
}
return m_refsTable;
}
/**
* Add an association between a ref and a node in the m_refsTable.
* Requires that m_refsTable != null
* @param xctxt XPath context
* @param ref the value of the use clause of the current key for the given node
* @param node the node to reference
*/
private void addValueInRefsTable(XPathContext xctxt, XMLString ref, int node) {
XNodeSet nodes = (XNodeSet) m_refsTable.get(ref);
if (nodes == null)
{
nodes = new XNodeSet(node, xctxt.getDTMManager());
nodes.nextNode();
m_refsTable.put(ref, nodes);
}
else
{
// Nodes are passed to this method in document order. Since we need to
// suppress duplicates, we only need to check against the last entry
// in each nodeset. We use nodes.nextNode after each entry so we can
// easily compare node against the current node.
if (nodes.getCurrentNode() != node) {
nodes.mutableNodeset().addNode(node);
nodes.nextNode();
}
}
}
}