package net.sf.saxon.functions;
import net.sf.saxon.expr.*;
import net.sf.saxon.om.Item;
import net.sf.saxon.om.NamespaceConstant;
import net.sf.saxon.om.NodeInfo;
import net.sf.saxon.sxpath.XPathEvaluator;
import net.sf.saxon.sxpath.XPathExpression;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.type.BuiltInAtomicType;
import net.sf.saxon.type.Type;
import net.sf.saxon.value.*;
/**
* Implement XPath function fn:error()
*/
public class Error extends SystemFunction {
/**
* preEvaluate: this method suppresses compile-time evaluation by doing nothing
* @param visitor an expression visitor
*/
public Expression preEvaluate(ExpressionVisitor visitor) {
return this;
}
/**
* Determine whether this is a vacuous expression as defined in the XQuery update specification
* @return true if this expression is vacuous
*/
public boolean isVacuousExpression() {
return true;
}
/**
* Evaluation of the expression always throws an error
*/
public Item evaluateItem(XPathContext context) throws XPathException {
QualifiedNameValue qname = null;
if (argument.length > 0) {
qname = (QualifiedNameValue)argument[0].evaluateItem(context);
}
if (qname == null) {
qname = new QNameValue("err", NamespaceConstant.ERR,
(argument.length == 1 ? "FOTY0004" : "FOER0000"),
BuiltInAtomicType.QNAME, null);
}
String description;
if (argument.length > 1) {
description = argument[1].evaluateItem(context).getStringValue();
} else {
description = "Error signalled by application call on error()";
}
XPathException e = new XPathException(description);
e.setErrorCodeQName(qname.toStructuredQName());
e.setXPathContext(context);
e.setLocator(this);
if (argument.length > 2) {
Value errorObject = ((Value)SequenceExtent.makeSequenceExtent(argument[2].iterate(context))).reduce();
if (errorObject instanceof SingletonItem) {
Item root = ((SingletonItem)errorObject).getItem();
if ((root instanceof NodeInfo) && ((NodeInfo)root).getNodeKind() == Type.DOCUMENT) {
XPathEvaluator xpath = new XPathEvaluator();
XPathExpression exp = xpath.createExpression("/error/@module");
NodeInfo moduleAtt = (NodeInfo)exp.evaluateSingle((NodeInfo)root);
String module = (moduleAtt == null ? null : moduleAtt.getStringValue());
exp = xpath.createExpression("/error/@line");
NodeInfo lineAtt = (NodeInfo)exp.evaluateSingle((NodeInfo)root);
int line = (lineAtt == null ? -1 : Integer.parseInt(lineAtt.getStringValue()));
exp = xpath.createExpression("/error/@column");
NodeInfo columnAtt = (NodeInfo)exp.evaluateSingle((NodeInfo)root);
int column = (columnAtt == null ? -1 : Integer.parseInt(columnAtt.getStringValue()));
ExpressionLocation locator = new ExpressionLocation();
locator.setSystemId(module);
locator.setLineNumber(line);
locator.setColumnNumber(column);
e.setLocator(locator);
}
}
e.setErrorObject(errorObject);
}
throw e;
}
/**
* Evaluate an updating expression, adding the results to a Pending Update List.
* The default implementation of this method, which is used for non-updating expressions,
* throws an UnsupportedOperationException
*
* @param context the XPath dynamic evaluation context
* @param pul the pending update list to which the results should be written
*/
public void evaluatePendingUpdates(XPathContext context, PendingUpdateList pul) throws XPathException {
evaluateItem(context);
}
}
//
// The contents of this file are subject to the Mozilla Public License Version 1.0 (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.mozilla.org/MPL/
//
// Software distributed under the License is distributed on an "AS IS" basis,
// WITHOUT WARRANTY OF ANY KIND, either express or implied.
// See the License for the specific language governing rights and limitations under the License.
//
// The Original Code is: all this file.
//
// The Initial Developer of the Original Code is Michael H. Kay.
//
// Portions created by (your name) are Copyright (C) (your legal entity). All Rights Reserved.
//
// Contributor(s): none.
//