Ok,my new code is as follows.I dont get any error now but the result string is an empty string what is impossible because "//situation" could never fail.
I'm certainly loading saxon now.

Any ideas?

String result = null;
        //String xpathExpressionStr = "max(//situation/situationRecord/situationRecordVersionTime/xs:dateTime(.) )";
        String xpathExpressionStr = "//situation";

        try
        {

            XPath xpath = new net.sf.saxon.xpath.XPathEvaluator();

            XPathExpression xpathExpression = xpath.compile(xpathExpressionStr);

            result = xpathExpression.evaluate(new InputSource(new StringReader(xml)));

            System.out.println("RESULT: "+ result);

        }
        catch(Exception e)
        {
            System.out.println("Error Eval(): "+ e.getMessage());
        }
        return result;

If //situation selects a set of nodes, then the way you are calling evaluate() that node-set will be converted to a string, which under the XPath 1.0 rules will give you the string value of the first element in the set. In the XML you showed us earlier, the string value of the situation element is an empty string.

Michael Kay
http://www.saxonica.com/
Author, XSLT Programmer's Reference and XPath 2.0 Programmer's Reference

My xml file is as follows:

<?xml version="1.0" encoding="UTF-8"?>

<d2LogicalModel xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:d2lm="D2LogicalModel" xmlns="http://datex2.eu/schema/1_0/1_0" modelBaseVersion="1.0" xsi:schemaLocation="http://datex2.eu/schema/1_0/1_0>
    <exchange>
        <supplierIdentification>
            <country>oiss</country>
            <nationalIdentifier>oiss001</nationalIdentifier>
        </supplierIdentification>
    </exchange>
    <payloadPublication xsi:type="SituationPublication" lang="es">
        <publicationTime>2007-03-12T15:20:00+01:00</publicationTime>
        <publicationCreator>
            <country>es</country>
            <nationalIdentifier>es001</nationalIdentifier>
        </publicationCreator>
        <situation id="GUID247153">
            <headerInformation>
                <confidentiality>noRestriction</confidentiality>
                <informationStatus>real</informationStatus>
            </headerInformation>
            <situationRecord xsi:type="MaintenanceWorks" id="GUID247153_3O">
                <situationRecordCreationTime>2006-02-06T11:22:00+01:00</situationRecordCreationTime>
                <situationRecordVersion>2</situationRecordVersion>
                <situationRecordVersionTime>2006-03-06T11:22:00+01:00</situationRecordVersionTime>
                <situationRecordFirstSupplierVersionTime>2006-02-06T11:22:00+01:00</situationRecordFirstSupplierVersionTime>
                <probabilityOfOccurrence>certain</probabilityOfOccurrence>
                <validity>
                    <validityStatus>active</validityStatus>
                    <validityTimeSpecification>
                        <overallStartTime>2006-10-17T14:00:00+02:00</overallStartTime>
                        <overallEndTime>2006-10-17T16:00:00+02:00</overallEndTime>
                    </validityTimeSpecification>
                </validity>
                <groupOfLocations>
                    <locationContainedInGroup xsi:type="Linear">
                        <alertCLinear xsi:type="aaa">
                            <alertCLocationCountryCode>W</alertCLocationCountryCode>
                            <alertCLocationTableNumber>0007</alertCLocationTableNumber>
                            <alertCLocationTableVersion>0000</alertCLocationTableVersion>
                            <alertCDirection>
                                <alertCDirectionCoded>both</alertCDirectionCoded>
                            </alertCDirection>
                            <alertCMethod4PrimaryPointLocation>
                                <alertCLocation>
                                    <specificLocation>62017</specificLocation>
                                </alertCLocation>
                                <offsetDistance>
                                    <offsetDistance>000987</offsetDistance>
                                </offsetDistance>
                            </alertCMethod4PrimaryPointLocation>
                            <alertCMethod4SecondaryPointLocation>
                                <alertCLocation>
                                    <specificLocation>62019</specificLocation>
                                </alertCLocation>
                                <offsetDistance>
                                    <offsetDistance>00098</offsetDistance>
                                </offsetDistance>
                            </alertCMethod4SecondaryPointLocation>
                        </alertCLinear>
                    </locationContainedInGroup>
                </groupOfLocations>
                <effectOnRoadLayout>roadLayoutUnchanged</effectOnRoadLayout>
                <roadMaintenanceType>roadworks</roadMaintenanceType>
            </situationRecord>
            <situationRecord xsi:type="NetworkManagement" id="GUID247153_1O">
                <situationRecordCreationTime>2006-02-06T12:22:00+01:00</situationRecordCreationTime>
                <situationRecordVersion>2</situationRecordVersion>
                <situationRecordVersionTime>2006-02-06T12:22:00+01:00</situationRecordVersionTime>
                <situationRecordFirstSupplierVersionTime>2006-02-06T11:22:00+01:00</situationRecordFirstSupplierVersionTime>
                <probabilityOfOccurrence>certain</probabilityOfOccurrence>
                <validity>
                    <validityStatus>active</validityStatus>
                    <validityTimeSpecification>
                        <overallStartTime>2006-10-17T14:00:00+02:00</overallStartTime>
                        <overallEndTime>2006-10-17T16:00:00+02:00</overallEndTime>
                    </validityTimeSpecification>
                </validity>
                <groupOfLocations>
                    <locationContainedInGroup xsi:type="Linear">
                        <alertCLinear xsi:type="AlertCMethod4Linear">
                            <alertCLocationCountryCode>E</alertCLocationCountryCode>
                            <alertCLocationTableNumber>17</alertCLocationTableNumber>
                            <alertCLocationTableVersion>2.0</alertCLocationTableVersion>
                            <alertCDirection>
                                <alertCDirectionCoded>both</alertCDirectionCoded>
                            </alertCDirection>
                            <alertCMethod4PrimaryPointLocation>
                                <alertCLocation>
                                    <specificLocation>62017</specificLocation>
                                </alertCLocation>
                                <offsetDistance>
                                    <offsetDistance>1650</offsetDistance>
                                </offsetDistance>
                            </alertCMethod4PrimaryPointLocation>
                            <alertCMethod4SecondaryPointLocation>
                                <alertCLocation>
                                    <specificLocation>62019</specificLocation>
                                </alertCLocation>
                                <offsetDistance>
                                    <offsetDistance>1650</offsetDistance>
                                </offsetDistance>
                            </alertCMethod4SecondaryPointLocation>
                        </alertCLinear>
                    </locationContainedInGroup>
                </groupOfLocations>
                <networkManagementType>restrictions</networkManagementType>
            </situationRecord>
        </situation>
    </payloadPublication>
</d2LogicalModel>


I want to select the latest date of the <situationRecordVersionTime> tag.Ive used the following query "max(//situation/situationRecord/situationRecordVersionTime/xs:dateTime(.))" and It also returns an empty string.Could you please help me with this query.

I think this query should not return a set of nodes.

THANKS!!

Your nodes are in a namespace: xmlns="http://datex2.eu/schema/1_0/1_0". Your XPath expression will only find them if it looks for them in this namespace, which is achieved by binding a prefix to the namespace and writing //p:situation.



Michael Kay
http://www.saxonica.com/
Author, XSLT Programmer's Reference and XPath 2.0 Programmer's Reference

I refer you to this thread, started by someone named Tomi. What exactly is it about default namespaces that you are not grasping?

--

Joe (Microsoft MVP - XML)