allow Ant references to be used for xslt attributes

WHATSNEW

@@ -86,6 +86,9 @@ Other changes:
  * it is now possible to set features of the TraX factory used by <xslt>
    and <junitreport>.
 
+ * it is now possible to use references to Ant types and classloaders
+   built around Ant <path>s as values for TraX factory attributes.
+
 Changes from Ant 1.9.6 TO Ant 1.9.7
 ===================================
 

manual/Tasks/style.html

@@ -431,9 +431,39 @@ And in Saxon 7.x:
   <tr>
     <td valign="top">value</td>
     <td valign="top">value of the attribute.</td>
-    <td align="center" valign="top">Yes</td>
+    <td align="center" valign="middle" rowspan="3">Exactly one of these</td>
+  </tr>
+  <tr>
+    <td valign="top">valueref</td>
+    <td valign="top">value of the attribute is the value of the
+      project reference with the given id. <em>since Ant 1.9.8</em></td>
+  </tr>
+  <tr>
+    <td valign="top">classloaderforpath</td>
+    <td valign="top">value of the attribute is a classloader that uses
+      the classpath specified by a path that is the project reference
+      with the given id. <em>since Ant 1.9.8</em></td>
   </tr>
 </table>
+
+<h4>Examples</h4>
+
+<pre>
+  &lt;path id="extension-path"&gt;
+    ...
+  &lt;/path&gt;
+
+
+  &lt;xslt ...&gt;
+    &lt;factory&gt;
+      &lt;attribute name="jdk.xml.transform.extensionClassLoader"
+                 classloaderforpath="extension-path"/&gt;
+    &lt;/factory&gt;
+  &lt;/xslt ...&gt;
+</pre>
+<p>Sets the classloader to use when loading extension functions to a
+  classloader using the <code>path</code> with the
+  id <code>extension-path</code>.
 </blockquote>
 <h4>feature</h4>
 <p><em>since Ant 1.9.8</em></p>

src/main/org/apache/tools/ant/taskdefs/XSLTProcess.java

@@ -39,6 +39,7 @@ import org.apache.tools.ant.BuildException;
 import org.apache.tools.ant.DirectoryScanner;
 import org.apache.tools.ant.DynamicConfigurator;
 import org.apache.tools.ant.Project;
+import org.apache.tools.ant.ProjectComponent;
 import org.apache.tools.ant.PropertyHelper;
 import org.apache.tools.ant.types.CommandlineJava;
 import org.apache.tools.ant.types.Environment;
@@ -53,6 +54,7 @@ import org.apache.tools.ant.types.resources.FileProvider;
 import org.apache.tools.ant.types.resources.FileResource;
 import org.apache.tools.ant.types.resources.Resources;
 import org.apache.tools.ant.types.resources.Union;
+import org.apache.tools.ant.util.ClasspathUtils;
 import org.apache.tools.ant.util.FileNameMapper;
 import org.apache.tools.ant.util.FileUtils;
 import org.apache.tools.ant.util.ResourceUtils;
@@ -1525,7 +1527,9 @@ public class XSLTProcess extends MatchingTask implements XSLTLogger {
          *  <li>http://xml.apache.org/xalan/features/incremental (true|false) </li>
          * </ul>
          */
-        public static class Attribute implements DynamicConfigurator {
+        public static class Attribute
+            extends ProjectComponent
+            implements DynamicConfigurator {
 
             /** attribute name, mostly processor specific */
             private String name;
@@ -1582,6 +1586,13 @@ public class XSLTProcess extends MatchingTask implements XSLTLogger {
                             this.value = value;
                         }
                     }
+                } else if ("valueref".equalsIgnoreCase(name)) {
+                    this.value = getProject().getReference(value);
+                } else if ("classloaderforpath".equalsIgnoreCase(name)) {
+                    this.value =
+                        ClasspathUtils.getClassLoaderForPath(getProject(),
+                                                             new Reference(getProject(),
+                                                                           value));
                 } else {
                     throw new BuildException("Unsupported attribute: " + name);
                 }