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/*
* 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.
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package com.sun.org.apache.xml.internal.security.utils;
import javax.xml.transform.TransformerException;
import com.sun.org.apache.xml.internal.security.transforms.implementations.FuncHereContext;
import com.sun.org.apache.xml.internal.utils.PrefixResolver;
import com.sun.org.apache.xml.internal.utils.PrefixResolverDefault;
import com.sun.org.apache.xpath.internal.XPath;
import com.sun.org.apache.xpath.internal.objects.XObject;
import org.w3c.dom.Attr;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.w3c.dom.ProcessingInstruction;
import org.w3c.dom.Text;
import org.w3c.dom.traversal.NodeIterator;
/**
* This class does the same as {@link com.sun.org.apache.xpath.internal.XPathAPI} except that the XPath strings
* are not supplied as Strings but as {@link Text}, {@link Attr}ibute or
* {ProcessingInstruction} nodes which contain the XPath string. This enables
* us to use the <CODE>here()</CODE> function.
* <BR>
* The methods in this class are convenience methods into the low-level XPath API.
* These functions tend to be a little slow, since a number of objects must be
* created for each evaluation. A faster way is to precompile the
* XPaths using the low-level API, and then just use the XPaths
* over and over.
*
* @author $Author: raul $
* @see <a href="http://www.w3.org/TR/xpath">XPath Specification</a>
*/
public class XPathFuncHereAPI {
/**
* Use an XPath string to select a single node. XPath namespace
* prefixes are resolved from the context node, which may not
* be what you want (see the next method).
*
* @param contextNode The node to start searching from.
* @param xpathnode A Node containing a valid XPath string.
* @return The first node found that matches the XPath, or null.
*
* @throws TransformerException
*/
public static Node selectSingleNode(Node contextNode, Node xpathnode)
throws TransformerException {
return selectSingleNode(contextNode, xpathnode, contextNode);
}
/**
* Use an XPath string to select a single node.
* XPath namespace prefixes are resolved from the namespaceNode.
*
* @param contextNode The node to start searching from.
* @param xpathnode
* @param namespaceNode The node from which prefixes in the XPath will be resolved to namespaces.
* @return The first node found that matches the XPath, or null.
*
* @throws TransformerException
*/
public static Node selectSingleNode(
Node contextNode, Node xpathnode, Node namespaceNode)
throws TransformerException {
// Have the XObject return its result as a NodeSetDTM.
NodeIterator nl = selectNodeIterator(contextNode, xpathnode,
namespaceNode);
// Return the first node, or null
return nl.nextNode();
}
/**
* Use an XPath string to select a nodelist.
* XPath namespace prefixes are resolved from the contextNode.
*
* @param contextNode The node to start searching from.
* @param xpathnode
* @return A NodeIterator, should never be null.
*
* @throws TransformerException
*/
public static NodeIterator selectNodeIterator(
Node contextNode, Node xpathnode) throws TransformerException {
return selectNodeIterator(contextNode, xpathnode, contextNode);
}
/**
* Use an XPath string to select a nodelist.
* XPath namespace prefixes are resolved from the namespaceNode.
*
* @param contextNode The node to start searching from.
* @param xpathnode
* @param namespaceNode The node from which prefixes in the XPath will be resolved to namespaces.
* @return A NodeIterator, should never be null.
*
* @throws TransformerException
*/
public static NodeIterator selectNodeIterator(
Node contextNode, Node xpathnode, Node namespaceNode)
throws TransformerException {
// Execute the XPath, and have it return the result
XObject list = eval(contextNode, xpathnode, namespaceNode);
// Have the XObject return its result as a NodeSetDTM.
return list.nodeset();
}
/**
* Use an XPath string to select a nodelist.
* XPath namespace prefixes are resolved from the contextNode.
*
* @param contextNode The node to start searching from.
* @param xpathnode
* @return A NodeIterator, should never be null.
*
* @throws TransformerException
*/
public static NodeList selectNodeList(Node contextNode, Node xpathnode)
throws TransformerException {
return selectNodeList(contextNode, xpathnode, contextNode);
}
/**
* Use an XPath string to select a nodelist.
* XPath namespace prefixes are resolved from the namespaceNode.
*
* @param contextNode The node to start searching from.
* @param xpathnode
* @param namespaceNode The node from which prefixes in the XPath will be resolved to namespaces.
* @return A NodeIterator, should never be null.
*
* @throws TransformerException
*/
public static NodeList selectNodeList(
Node contextNode, Node xpathnode, Node namespaceNode)
throws TransformerException {
// Execute the XPath, and have it return the result
XObject list = eval(contextNode, xpathnode, namespaceNode);
// Return a NodeList.
return list.nodelist();
}
/**
* Evaluate XPath string to an XObject. Using this method,
* XPath namespace prefixes will be resolved from the namespaceNode.
* @param contextNode The node to start searching from.
* @param xpathnode
* @return An XObject, which can be used to obtain a string, number, nodelist, etc, should never be null.
* @see com.sun.org.apache.xpath.internal.objects.XObject
* @see com.sun.org.apache.xpath.internal.objects.XNull
* @see com.sun.org.apache.xpath.internal.objects.XBoolean
* @see com.sun.org.apache.xpath.internal.objects.XNumber
* @see com.sun.org.apache.xpath.internal.objects.XString
* @see com.sun.org.apache.xpath.internal.objects.XRTreeFrag
*
* @throws TransformerException
*/
public static XObject eval(Node contextNode, Node xpathnode)
throws TransformerException {
return eval(contextNode, xpathnode, contextNode);
}
/**
* Evaluate XPath string to an XObject.
* XPath namespace prefixes are resolved from the namespaceNode.
* The implementation of this is a little slow, since it creates
* a number of objects each time it is called. This could be optimized
* to keep the same objects around, but then thread-safety issues would arise.
*
* @param contextNode The node to start searching from.
* @param xpathnode
* @param namespaceNode The node from which prefixes in the XPath will be resolved to namespaces.
* @return An XObject, which can be used to obtain a string, number, nodelist, etc, should never be null.
* @see com.sun.org.apache.xpath.internal.objects.XObject
* @see com.sun.org.apache.xpath.internal.objects.XNull
* @see com.sun.org.apache.xpath.internal.objects.XBoolean
* @see com.sun.org.apache.xpath.internal.objects.XNumber
* @see com.sun.org.apache.xpath.internal.objects.XString
* @see com.sun.org.apache.xpath.internal.objects.XRTreeFrag
*
* @throws TransformerException
*/
public static XObject eval(
Node contextNode, Node xpathnode, Node namespaceNode)
throws TransformerException {
// Since we don't have a XML Parser involved here, install some default support
// for things like namespaces, etc.
// (Changed from: XPathContext xpathSupport = new XPathContext();
// because XPathContext is weak in a number of areas... perhaps
// XPathContext should be done away with.)
FuncHereContext xpathSupport = new FuncHereContext(xpathnode);
// 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).
PrefixResolverDefault prefixResolver =
new PrefixResolverDefault((namespaceNode.getNodeType()
== Node.DOCUMENT_NODE)
? ((Document) namespaceNode)
.getDocumentElement()
: namespaceNode);
String str = getStrFromNode(xpathnode);
// Create the XPath object.
XPath xpath = new XPath(str, null, prefixResolver, XPath.SELECT, null);
// Execute the XPath, and have it return the result
// return xpath.execute(xpathSupport, contextNode, prefixResolver);
int ctxtNode = xpathSupport.getDTMHandleFromNode(contextNode);
return xpath.execute(xpathSupport, ctxtNode, prefixResolver);
}
/**
* Evaluate XPath string to an XObject.
* XPath namespace prefixes are resolved from the namespaceNode.
* The implementation of this is a little slow, since it creates
* a number of objects each time it is called. This could be optimized
* to keep the same objects around, but then thread-safety issues would arise.
*
* @param contextNode The node to start searching from.
* @param xpathnode
* @param prefixResolver Will be called if the parser encounters namespace
* prefixes, to resolve the prefixes to URLs.
* @return An XObject, which can be used to obtain a string, number, nodelist, etc, should never be null.
* @see com.sun.org.apache.xpath.internal.objects.XObject
* @see com.sun.org.apache.xpath.internal.objects.XNull
* @see com.sun.org.apache.xpath.internal.objects.XBoolean
* @see com.sun.org.apache.xpath.internal.objects.XNumber
* @see com.sun.org.apache.xpath.internal.objects.XString
* @see com.sun.org.apache.xpath.internal.objects.XRTreeFrag
*
* @throws TransformerException
*/
public static XObject eval(
Node contextNode, Node xpathnode, PrefixResolver prefixResolver)
throws TransformerException {
String str = getStrFromNode(xpathnode);
// Since we don't have a XML Parser involved here, install some default support
// for things like namespaces, etc.
// (Changed from: XPathContext xpathSupport = new XPathContext();
// because XPathContext is weak in a number of areas... perhaps
// XPathContext should be done away with.)
// Create the XPath object.
XPath xpath = new XPath(str, null, prefixResolver, XPath.SELECT, null);
// Execute the XPath, and have it return the result
FuncHereContext xpathSupport = new FuncHereContext(xpathnode);
int ctxtNode = xpathSupport.getDTMHandleFromNode(contextNode);
return xpath.execute(xpathSupport, ctxtNode, prefixResolver);
}
/**
* Method getStrFromNode
*
* @param xpathnode
* @return the string from the node
*/
private static String getStrFromNode(Node xpathnode) {
if (xpathnode.getNodeType() == Node.TEXT_NODE) {
return ((Text) xpathnode).getData();
} else if (xpathnode.getNodeType() == Node.ATTRIBUTE_NODE) {
return ((Attr) xpathnode).getNodeValue();
} else if (xpathnode.getNodeType() == Node.PROCESSING_INSTRUCTION_NODE) {
return ((ProcessingInstruction) xpathnode).getNodeValue();
}
return "";
}
}