/*
* © Copyright IBM Corp. 2012
*
* 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.
*/
package com.ibm.commons.xml.drivers;
import javax.xml.transform.TransformerException;
import org.apache.xml.utils.PrefixResolver;
import org.apache.xpath.XPathAPI;
import org.apache.xpath.objects.XObject;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import com.ibm.commons.util.StringUtil;
import com.ibm.commons.xml.NamespaceContext;
import com.ibm.commons.xml.XResult;
import com.ibm.commons.xml.XResultUtils;
import com.ibm.commons.xml.xpath.NodeListImpl;
import com.ibm.commons.xml.xpath.XPathException;
/**
* JAXP Driver using Xerces as the XPath engine.
*/
public class JAXPDriverXerces extends AbstractJAXPDriver {
// =========================================================================================
// XPATH
// =========================================================================================
// PHIL: temporary.
// Not optimized method. Should move to a precompiled XPath object
public Object createXPath(String xpath) throws XPathException {
return xpath;
}
public XResult evaluateXPath(Node node, Object xpath, NamespaceContext nsContext) throws XPathException {
try {
PrefixResolver pr = nsContext!=null ? new NSResolver(nsContext) : null;
XObject res = XPathAPI.eval(node,(String)xpath,pr);
return convertResult(res);
} catch(Exception e) {
throw new XPathException(e,"Error while evaluating XPath {0}",xpath.toString()); // $NLS-AbstractXercesDriver.ErrorwhileevaluatingXPath0-1$
}
}
public XResult evaluateXPath(NodeList nodeList, Object xpath, NamespaceContext nsContext) throws XPathException {
try {
if(nodeList.getLength()>0) {
XResult result = null;
NodeListImpl nodes = null;
PrefixResolver pr = nsContext!=null ? new NSResolver(nsContext) : null;
for( int i=0; i<nodeList.getLength(); i++ ) {
XObject res = XPathAPI.eval(nodeList.item(i),(String)xpath,pr);
switch(res.getType()) {
case XObject.CLASS_BOOLEAN: {
if(nodes!=null) {
throw new XPathException(null,"XPath result cannot contain both values and nodes"); // $NLS-AbstractXercesDriver.AnXPathresultcannotcontainbothval-1$
}
if(result!=null) {
throw new XPathException(null,"XPath exception cannot return multiple values"); // $NLS-AbstractXercesDriver.AnXPathExceptioncannotreturnmulti-1$
}
result = new XResultUtils.BooleanValue(res.bool());
} break;
case XObject.CLASS_NUMBER: {
if(nodes!=null) {
throw new XPathException(null,"XPath result cannot contain both values and nodes"); // $NLS-AbstractXercesDriver.AnXPathresultcannotcontainbothval.1-1$
}
if(result!=null) {
throw new XPathException(null,"XPath exception cannot return multiple values"); // $NLS-AbstractXercesDriver.AnXPathExceptioncannotreturnmulti.1-1$
}
result = new XResultUtils.NumberValue(res.num());
} break;
case XObject.CLASS_STRING: {
if(nodes!=null) {
throw new XPathException(null,"XPath result cannot contain both values and nodes"); // $NLS-AbstractXercesDriver.AnXPathresultcannotcontainbothval.2-1$
}
if(result!=null) {
throw new XPathException(null,"XPath exception cannot return multiple values"); // $NLS-AbstractXercesDriver.AnXPathExceptioncannotreturnmulti.2-1$
}
result = new XResultUtils.StringValue(res.str());
} break;
case XObject.CLASS_NODESET: {
if(result!=null) {
throw new XPathException(null,"XPath result cannot contain both values and nodes"); // $NLS-AbstractXercesDriver.AnXPathresultcannotcontainbothval.3-1$
}
NodeList nl = res.nodelist();
int len = nl.getLength();
if(len>0) {
if(nodes==null) {
nodes = new NodeListImpl();
}
for( int j=0; j<nl.getLength(); j++ ) {
nodes.add(nl.item(j));
}
}
}
}
}
if(result!=null) {
return result;
}
if(nodes!=null) {
int len = nodes.getLength();
if(len==0) {
return XResultUtils.emptyResult;
} else if(len==1) {
return new XResultUtils.XMLNode(nodes.item(0));
} else {
return new XResultUtils.XMLNodeList(nodes);
}
}
}
return XResultUtils.emptyResult;
} catch(Exception e) {
throw new XPathException(e,"Error evaluating XPath {0}",xpath.toString()); // $NLS-AbstractXercesDriver.ErrorwhileevaluatingXPath0.1-1$
}
}
private static class NSResolver implements PrefixResolver {
NamespaceContext nsContext;
NSResolver(NamespaceContext nsContext) {
this.nsContext = nsContext;
}
public String getNamespaceForPrefix(String prefix) {
return nsContext.getNamespaceURI(prefix);
}
public String getNamespaceForPrefix(String prefix, org.w3c.dom.Node context) {
return nsContext.getNamespaceURI(prefix);
}
public boolean handlesNullPrefixes() {
String nsUri = nsContext.getNamespaceURI("");
return !StringUtil.isEmpty(nsUri);
}
// PHIL: not sure what to do here...
public String getBaseIdentifier() {
return "";
}
}
private static XResult convertResult(XObject object) throws TransformerException {
switch(object.getType()) {
//case XObject.CLASS_UNKNOWN:
//case XObject.CLASS_NULL:
// break;
case XObject.CLASS_BOOLEAN: {
return new XResultUtils.BooleanValue(object.bool());
}
case XObject.CLASS_NUMBER: {
return new XResultUtils.NumberValue(object.num());
}
case XObject.CLASS_STRING: {
return new XResultUtils.StringValue(object.str());
}
case XObject.CLASS_NODESET: {
final NodeList nl = object.nodelist();
final int len = nl.getLength();
if(len==0) {
return XResultUtils.emptyResult;
} else if(len==1) {
return new XResultUtils.XMLNode(nl.item(0));
} else {
return new XResultUtils.XMLNodeList(nl);
}
}
//case CLASS_RTREEFRAG: {
//CLASS_UNRESOLVEDVARIABLE = 600;
}
return XResultUtils.emptyResult;
}
}