XalanXPathExpression.java
/*--
Copyright (C) 2011-2014 Jason Hunter & Brett McLaughlin.
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
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provided with the distribution.
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derived from this software without prior written permission. For
written permission, please contact <request_AT_jdom_DOT_org>.
4. Products derived from this software may not be called "JDOM", nor
may "JDOM" appear in their name, without prior written permission
from the JDOM Project Management <request_AT_jdom_DOT_org>.
In addition, we request (but do not require) that you include in the
end-user documentation provided with the redistribution and/or in the
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"This product includes software developed by the
JDOM Project (http://www.jdom.org/)."
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THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
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OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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This software consists of voluntary contributions made by many
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created by Jason Hunter <jhunter_AT_jdom_DOT_org> and
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on the JDOM Project, please see <http://www.jdom.org/>.
*/
package org.jdom2.contrib.xpath.xalan;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import javax.xml.transform.TransformerException;
import org.apache.xml.utils.PrefixResolver;
import org.apache.xml.utils.QName;
import org.apache.xpath.VariableStack;
import org.apache.xpath.XPath;
import org.apache.xpath.XPathContext;
import org.apache.xpath.axes.NodeSequence;
import org.apache.xpath.objects.XObject;
import org.w3c.dom.Attr;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.jdom2.Attribute;
import org.jdom2.CDATA;
import org.jdom2.Comment;
import org.jdom2.Content;
import org.jdom2.DocType;
import org.jdom2.Document;
import org.jdom2.Element;
import org.jdom2.EntityRef;
import org.jdom2.Namespace;
import org.jdom2.NamespaceAware;
import org.jdom2.ProcessingInstruction;
import org.jdom2.Text;
import org.jdom2.contrib.dom.DOM;
import org.jdom2.contrib.dom.Wrapper;
import org.jdom2.filter.Filter;
import org.jdom2.xpath.util.AbstractXPathCompiled;
/**
* An XPathExpression that wraps the JDOM content in DOM wrappers
* and then uses the Direct Xalan API to implement XPath.
*
* @author Rolf Lear
*
* @param <T> the type of the coerced results.
*/
class XalanXPathExpression<T> extends AbstractXPathCompiled <T> implements PrefixResolver {
private final XPath xpath;
private final VariableStack variables = new VariableStack() {
@Override
public XObject getVariableOrParam(XPathContext xctxt, QName qname)
throws TransformerException {
if (qname == null) {
throw new IllegalArgumentException("Null qname");
}
final Object varValue = getVariable(qname.getLocalName(),
Namespace.getNamespace(qname.getNamespaceURI()));
if ( varValue == null ) {
throw new TransformerException(
"No such variable " + qname.toNamespacedString());
}
return XObject.create(varValue, xctxt);
}
};
/**
* Construct the XPathExpression.
* @param query The XPath query to create.
* @param filter The coercion filter.
* @param variables The variable map
* @param namespaces The scope namespaces.
*/
public XalanXPathExpression(final String query, final Filter<T> filter,
final Map<String, Object> variables, final Namespace[] namespaces) {
super(query, filter, variables, namespaces);
// Create an object to resolve namespace prefixes.
// XPath namespaces are resolved from the input context node's document element
// if it is a root node, or else the current context node (for lack of a better
// resolution space, given the simplicity of this sample code).
// Create the XPath object.
try {
xpath = new XPath(query, null, this, XPath.SELECT, null);
} catch (TransformerException e) {
throw new IllegalArgumentException("Unable to parse: " + query, e);
}
}
private final Node wrap(Object context) {
if (context == null) {
return DOM.wrap(new Document(), false);
}
if (context instanceof Document) {
return DOM.wrap((Document)context);
}
if (context instanceof Content) {
switch (((Content)context).getCType()) {
case CDATA:
return DOM.wrap((CDATA)context);
case Comment:
return DOM.wrap((Comment)context);
case DocType:
return DOM.wrap((DocType)context);
case Element:
return DOM.wrap((Element)context);
case EntityRef:
return DOM.wrap((EntityRef)context);
case ProcessingInstruction:
return DOM.wrap((ProcessingInstruction)context);
case Text:
return DOM.wrap((Text)context);
}
}
if (context instanceof Attribute) {
return DOM.wrap((Attribute)context);
}
throw new IllegalArgumentException("Unable to wrap context: " + context);
}
@Override
protected List<?> evaluateRawAll(Object context) {
// Execute the XPath, and have it return the result
// return xpath.execute(xpathSupport, contextNode, prefixResolver);
final XPathContext xpathSupport = new XPathContext(false);
xpathSupport.setVarStack(variables);
final Node contextNode = wrap(context);
final int ctxtNode = xpathSupport.getDTMHandleFromNode(contextNode);
try {
final XObject xo = xpath.execute(xpathSupport, ctxtNode, this);
ArrayList<Object> ret = new ArrayList<Object>();
if (xo instanceof NodeSequence) {
final NodeList nl = ((NodeSequence)xo).nodelist();
final int len = nl.getLength();
for (int i = 0; i < len; i++) {
Node n = nl.item(i);
if (n instanceof Wrapper) {
ret.add(((Wrapper)n).getWrapped());
} else if (n instanceof Attr) {
// probably a Namespace in the form of an Attr.
final Attr nsa = (Attr)n;
if ("xmlns".equals(nsa.getLocalName())) {
ret.add(Namespace.getNamespace(nsa.getValue()));
} else if (nsa.getName().startsWith("xmlns")) {
ret.add(Namespace.getNamespace(
nsa.getLocalName(), nsa.getValue()));
} else {
throw new IllegalStateException(
"Unexpected Attribute " + nsa.getName() +
"=\"" + nsa.getValue() + "\"");
}
} else {
throw new IllegalStateException(
"Unexpected Node " + n.getNodeName());
}
}
} else {
ret.add(xo.object());
}
return ret;
} catch (TransformerException te) {
throw new IllegalArgumentException("Unable to process xpath.", te);
}
}
@Override
protected Object evaluateRawFirst(Object context) {
List<?> raw = evaluateRawAll(context);
if (raw.isEmpty()) {
return null;
}
return raw.get(0);
}
@Override
public String getNamespaceForPrefix(String prefix) {
return getNamespace(prefix).getURI();
}
@Override
public String getNamespaceForPrefix(String prefix, Node context) {
if (context == null) {
return getNamespace(prefix).getPrefix();
}
if (prefix == null) {
prefix = "";
}
if (context instanceof Wrapper) {
Object o = ((Wrapper)context).getWrapped();
if ((o instanceof NamespaceAware)) {
for (Namespace ns : ((NamespaceAware)o).getNamespacesInScope()) {
if (ns.getPrefix().equals(prefix)) {
return ns.getURI();
}
}
}
}
return null;
}
@Override
public String getBaseIdentifier() {
return null;
}
@Override
public boolean handlesNullPrefixes() {
return false;
}
}