/*
GNU GENERAL LICENSE
Copyright (C) 2006 The Lobo Project. Copyright (C) 2014 - 2017 Lobo Evolution
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public
License as published by the Free Software Foundation; either
verion 3 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General License for more details.
You should have received a copy of the GNU General Public
along with this program. If not, see <http://www.gnu.org/licenses/>.
Contact info: lobochief@users.sourceforge.net; ivan.difrancesco@yahoo.it
*/
/*
* $Id: XPathExpressionImpl.java 1225426 2011-12-29 04:13:08Z mrglavas $
*/
package org.lobobrowser.html.xpath;
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.lobobrowser.w3c.xpath.XPathException;
import org.lobobrowser.w3c.xpath.XPathExpression;
import org.lobobrowser.w3c.xpath.XPathNamespace;
import org.w3c.dom.DOMException;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
/**
*
* The class provides an implementation of XPathExpression according to the DOM
* L3 XPath Specification, Working Group Note 26 February 2004.
*
* <p>
* See also the
* <a href='http://www.w3.org/TR/2004/NOTE-DOM-Level-3-XPath-20040226'>Document
* Object Model (DOM) Level 3 XPath Specification</a>. </p>
*
* <p> The <code>XPathExpression</code> interface represents a parsed and
* resolved XPath expression. </p>
*
* @see org.w3c.dom.xpath.XPathExpression
*
* @xsl.usage internal
*/
public 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.
*
* <p>
* See also the <a href=
* 'http://www.w3.org/TR/2004/NOTE-DOM-Level-3-XPath-20040226'>Document
* Object Model (DOM) Level 3 XPath Specification</a>. </p>
*
* <p> Evaluates this XPath expression and returns a result. </p>
*
* @param contextNode
* The <code>context</code> is context node for the evaluation of
* this XPath expression.If the XPathEvaluator was obtained by
* casting the <code>Document</code> then this must be owned by
* the same document and must be a <code>Document</code>,
* <code>Element</code>, <code>Attribute</code>,
* <code>Text</code>, <code>CDATASection</code>,
* <code>Comment</code>, <code>ProcessingInstruction</code>, or
* <code>XPathNamespace</code> node.If the context node is a
* <code>Text</code> or a <code>CDATASection</code>, 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 <code>type</code> 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 <code>XPathResult</code>
* .
* @param result
* The <code>result</code> specifies a specific result object
* which may be reused and returned by this method. If this is
* specified as <code>null</code>or 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 <code>XPathResult</code>.
* @return The result of the evaluation of the XPath expression.For XPath
* 1.0 results, this object will be of type <code>XPathResult</code>
* .
* @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
* <code>XPathExpression</code>. <br>
* 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
*/
@Override
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 != Node.DOCUMENT_NODE) && (nodeType != Node.ELEMENT_NODE) && (nodeType != Node.ATTRIBUTE_NODE)
&& (nodeType != Node.TEXT_NODE) && (nodeType != Node.CDATA_SECTION_NODE)
&& (nodeType != Node.COMMENT_NODE) && (nodeType != Node.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);
}
// 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);
}
}