org.apache.xpath.domapi.XPathExpressionImpl Maven / Gradle / Ivy
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* 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: XPathExpressionImpl.java 1225426 2011-12-29 04:13:08Z mrglavas $
*/
package org.apache.xpath.domapi;
import javax.xml.transform.TransformerException;
import org.apache.xpath.XPath;
import org.apache.xpath.XPathContext;
import org.apache.xpath.objects.XObject;
import org.apache.xpath.res.XPATHErrorResources;
import org.apache.xpath.res.XPATHMessages;
import org.w3c.dom.DOMException;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.xpath.XPathException;
import org.w3c.dom.xpath.XPathExpression;
import org.w3c.dom.xpath.XPathNamespace;
/**
*
* The class provides an implementation of XPathExpression according
* to the DOM L3 XPath Specification, Working Group Note 26 February 2004.
*
* See also the Document Object Model (DOM) Level 3 XPath Specification.
*
* The XPathExpression interface represents a parsed and resolved
* XPath expression.
*
* @see org.w3c.dom.xpath.XPathExpression
*
* @xsl.usage internal
*/
class XPathExpressionImpl implements XPathExpression {
/**
* The xpath object that this expression wraps
*/
final private XPath m_xpath;
/**
* The document to be searched to parallel the case where the XPathEvaluator
* is obtained by casting a Document.
*/
final private Document m_doc;
/**
* Constructor for XPathExpressionImpl.
*
* @param xpath The wrapped XPath object.
* @param doc The document to be searched, to parallel the case where''
* the XPathEvaluator is obtained by casting the document.
*/
XPathExpressionImpl(XPath xpath, Document doc) {
m_xpath = xpath;
m_doc = doc;
}
/**
*
* This method provides an implementation XPathResult.evaluate according
* to the DOM L3 XPath Specification, Working Group Note 26 February 2004.
*
* See also the Document Object Model (DOM) Level 3 XPath Specification.
*
* Evaluates this XPath expression and returns a result.
* @param contextNode The context is context node for the
* evaluation of this XPath expression.If the XPathEvaluator was
* obtained by casting the Document then this must be
* owned by the same document and must be a Document,
* Element, Attribute, Text,
* CDATASection, Comment,
* ProcessingInstruction, or XPathNamespace
* node.If the context node is a Text or a
* CDATASection, then the context is interpreted as the
* whole logical text node as seen by XPath, unless the node is empty
* in which case it may not serve as the XPath context.
* @param type If a specific type is specified, then the
* result will be coerced to return the specified type relying on
* XPath conversions and fail if the desired coercion is not possible.
* This must be one of the type codes of XPathResult.
* @param result The result specifies a specific result
* object which may be reused and returned by this method. If this is
* specified as nullor the implementation does not reuse
* the specified result, a new result object will be constructed and
* returned.For XPath 1.0 results, this object will be of type
* XPathResult.
* @return The result of the evaluation of the XPath expression.For XPath
* 1.0 results, this object will be of type XPathResult.
* @exception XPathException
* TYPE_ERR: Raised if the result cannot be converted to return the
* specified type.
* @exception DOMException
* WRONG_DOCUMENT_ERR: The Node is from a document that is not supported
* by the XPathEvaluator that created this
* XPathExpression.
*
NOT_SUPPORTED_ERR: The Node is not a type permitted as an XPath
* context node.
*
* @see org.w3c.dom.xpath.XPathExpression#evaluate(Node, short, XPathResult)
* @xsl.usage internal
*/
public Object evaluate(
Node contextNode,
short type,
Object result)
throws XPathException, DOMException {
// If the XPathEvaluator was determined by "casting" the document
if (m_doc != null) {
// Check that the context node is owned by the same document
if ((contextNode != m_doc) && (!contextNode.getOwnerDocument().equals(m_doc))) {
String fmsg = XPATHMessages.createXPATHMessage(XPATHErrorResources.ER_WRONG_DOCUMENT, null);
throw new DOMException(DOMException.WRONG_DOCUMENT_ERR, fmsg);
}
// Check that the context node is an acceptable node type
short nodeType = contextNode.getNodeType();
if ((nodeType != Document.DOCUMENT_NODE) &&
(nodeType != Document.ELEMENT_NODE) &&
(nodeType != Document.ATTRIBUTE_NODE) &&
(nodeType != Document.TEXT_NODE) &&
(nodeType != Document.CDATA_SECTION_NODE) &&
(nodeType != Document.COMMENT_NODE) &&
(nodeType != Document.PROCESSING_INSTRUCTION_NODE) &&
(nodeType != XPathNamespace.XPATH_NAMESPACE_NODE)) {
String fmsg = XPATHMessages.createXPATHMessage(XPATHErrorResources.ER_WRONG_NODETYPE, null);
throw new DOMException(DOMException.NOT_SUPPORTED_ERR, fmsg);
}
}
//
// If the type is not a supported type, throw an exception and be
// done with it!
if (!XPathResultImpl.isValidType(type)) {
String fmsg = XPATHMessages.createXPATHMessage(XPATHErrorResources.ER_INVALID_XPATH_TYPE, new Object[] {new Integer(type)});
throw new XPathException(XPathException.TYPE_ERR,fmsg); // Invalid XPath type argument: {0}
}
// Create an XPathContext that doesn't support pushing and popping of
// variable resolution scopes. Sufficient for simple XPath 1.0
// expressions.
// Cache xpath context?
XPathContext xpathSupport = new XPathContext(false);
// if m_document is not null, build the DTM from the document
if (null != m_doc) {
xpathSupport.getDTMHandleFromNode(m_doc);
}
XObject xobj = null;
try {
xobj = m_xpath.execute(xpathSupport, contextNode, null);
} catch (TransformerException te) {
// What should we do here?
throw new XPathException(XPathException.INVALID_EXPRESSION_ERR,te.getMessageAndLocation());
}
// Create a new XPathResult object
// Reuse result object passed in?
// The constructor will check the compatibility of type and xobj and
// throw an exception if they are not compatible.
return new XPathResultImpl(type,xobj,contextNode, m_xpath);
}
}