[jira] [Commented] (XMLBEANS-561) XPath support for namespace prefix to URI mappings

["Dimitrios Lagkouvardos (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/XMLBEANS-561?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17526682#comment-17526682 ] 

Dimitrios Lagkouvardos commented on XMLBEANS-561:
-------------------------------------------------

Hi PJ,

Adding the namespace declaration to the xpath expression resolved the XPathException. However, the query returns xml-fragment, which results in ClassCastException:
{noformat}
java.lang.ClassCastException: org.apache.xmlbeans.impl.values.XmlAnyTypeImpl cannot be cast to test.xb.EmployeeType{noformat}
*I've tried xb 5.0.0 and 5.0.3 with Saxon 10.6 and 10.8.*

I've used the employeeschema.xsd and employees.xml of [https://xmlbeans.apache.org/samples/XQueryXPath.html] and put together 2 simple test cases using XmlObject.selectPath and XmlCursor.selectPath.
{noformat}
  public static void xpathTest1(final File f) {
    final String namespaceDeclaration =
        "declare namespace xq='http://xmlbeans.apache.org/samples/xquery/employees'; ";
    String pathExpression = "$this/xq:employees/xq:employee";
    XmlObject xmlObj = parse(f);
    XmlObject[] results = xmlObj.selectPath(namespaceDeclaration + pathExpression);
    if (results.length > 0) {
      for (XmlObject o : results) {
        System.out.println(XMLHelper.getXmlBeanAsString(o, null));
        EmployeeType e = (EmployeeType) o; // java.lang.ClassCastException
      }
    }
  }  

  public static void xpathTest2(final File f) {
    final String namespaceDeclaration =
        "declare namespace xq='http://xmlbeans.apache.org/samples/xquery/employees'; ";
    String pathExpression = "$this/xq:employees/xq:employee";
    XmlObject xmlObj = parse(f);
    XmlCursor cursor = xmlObj.newCursor();
    cursor.selectPath(namespaceDeclaration + pathExpression);
    while (cursor.toNextSelection()) {
      System.out.println(XMLHelper.getXmlBeanAsString(cursor.getObject(), null));
      EmployeeType e = (EmployeeType) cursor.getObject(); // java.lang.ClassCastException
    }
  }{noformat}
This is the returned fragment:
{noformat}
<xml-fragment xmlns:emp="http://xmlbeans.apache.org/samples/xquery/employees">
  <emp:name>Fred Jones</emp:name>
  <emp:address location="home">
    <emp:street>900 Aurora Ave.</emp:street>
    <emp:city>Seattle</emp:city>
    <emp:state>WA</emp:state>
    <emp:zip>98115</emp:zip>
  </emp:address>
  <emp:address location="work">
    <emp:street>2011 152nd Avenue NE</emp:street>
    <emp:city>Redmond</emp:city>
    <emp:state>WA</emp:state>
    <emp:zip>98052</emp:zip>
  </emp:address>
  <emp:phone location="work">(425)555-5665</emp:phone>
  <emp:phone location="home">(206)555-5555</emp:phone>
  <emp:phone location="mobile">(206)555-4321</emp:phone>
</xml-fragment>{noformat}
Thank you.

 

> XPath support for namespace prefix to URI mappings
> --------------------------------------------------
>
>                 Key: XMLBEANS-561
>                 URL: https://issues.apache.org/jira/browse/XMLBEANS-561
>             Project: XMLBeans
>          Issue Type: Improvement
>          Components: XPath
>    Affects Versions: Version 5.0.0
>            Reporter: Dimitrios Lagkouvardos
>            Priority: Major
>
> 5.0.0 supports Saxon and an XmlBeans xpath engine. I don't see a way to configure or supply at runtime namespace prefix to URI mappings.
> *Suggestions*:
> 1) One solution is to enhance XmlObject.selectPath(String,XmlOptions) to use the namespaces returned by XmlOptions.getLoadAdditionalNamespaces (or perhaps add a new method if this is deemed inappropriate).
> 2) An alternative is to add an extension to retrieve the mappings to be passed to the xpath engine (instead of passing it on each call to selectPath).
> *Note*: Adding the namespace declaration to the xpath expression as documented in [http://xmlbeans.apache.org/guide/XPathXQuery.html] does NOT work:
> ```
> java.lang.RuntimeException: net.sf.saxon.trans.XPathException: Namespace prefix 'table' has not been declared
>  at org.apache.xmlbeans.impl.xpath.saxon.SaxonXPath.selectNodes(SaxonXPath.java:128)
>  at org.apache.xmlbeans.impl.xpath.saxon.SaxonXPath.selectPath(SaxonXPath.java:133)
>  at org.apache.xmlbeans.impl.xpath.saxon.SaxonXPathEngine.next(SaxonXPathEngine.java:60)
>  at org.apache.xmlbeans.impl.store.Cursor._toSelection(Cursor.java:749)
>  at org.apache.xmlbeans.impl.store.Cursor._toNextSelection(Cursor.java:736)
>  at org.apache.xmlbeans.impl.store.Cursor._hasNextSelection(Cursor.java:728)
>  at org.apache.xmlbeans.impl.store.Cursor.syncWrapHelper(Cursor.java:2520)
>  at org.apache.xmlbeans.impl.store.Cursor.syncWrap(Cursor.java:2451)
>  at org.apache.xmlbeans.impl.store.Cursor.hasNextSelection(Cursor.java:2022)
>  at org.apache.xmlbeans.impl.values.XmlObjectBase.selectPath(XmlObjectBase.java:496)
> ```
>  



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