Added getDocument

xml/src/main/java/org/springframework/xml/transform/TraxUtils.java

@@ -23,9 +23,13 @@ import javax.xml.stream.XMLStreamReader;
 import javax.xml.stream.XMLStreamWriter;
 import javax.xml.transform.Result;
 import javax.xml.transform.Source;
+import javax.xml.transform.dom.DOMSource;
 import javax.xml.transform.stax.StAXResult;
 import javax.xml.transform.stax.StAXSource;
 
+import org.w3c.dom.Document;
+import org.w3c.dom.Node;
+
 import org.springframework.util.Assert;
 import org.springframework.xml.JaxpVersion;
 
@@ -186,6 +190,22 @@ public abstract class TraxUtils {
         }
     }
 
+    /**
+     * Returns the {@link Document} of the given {@link DOMSource}.
+     *
+     * @param source the DOM source
+     * @return the document
+     */
+    public static Document getDocument(DOMSource source) {
+        Node node = source.getNode();
+        if (node instanceof Document) {
+            return (Document) node;
+        }
+        else {
+            return node.getOwnerDocument();
+        }
+    }
+
     /** Inner class to avoid a static JAXP 1.4 dependency. */
     private static class Jaxp14StaxHandler {
 

xml/src/test/java/org/springframework/xml/transform/TraxUtilsTest.java

@@ -18,6 +18,8 @@ package org.springframework.xml.transform;
 
 import java.io.StringReader;
 import java.io.StringWriter;
+import javax.xml.parsers.DocumentBuilder;
+import javax.xml.parsers.DocumentBuilderFactory;
 import javax.xml.stream.XMLEventReader;
 import javax.xml.stream.XMLEventWriter;
 import javax.xml.stream.XMLInputFactory;
@@ -37,6 +39,8 @@ import javax.xml.transform.stream.StreamResult;
 import javax.xml.transform.stream.StreamSource;
 
 import org.custommonkey.xmlunit.XMLTestCase;
+import org.w3c.dom.Document;
+import org.w3c.dom.Element;
 
 public class TraxUtilsTest extends XMLTestCase {
 
@@ -189,4 +193,15 @@ public class TraxUtilsTest extends XMLTestCase {
 
         assertEquals("Invalid XMLEventWriter", eventWriter, TraxUtils.getXMLEventWriter(result));
     }
+
+    public void testGetDocument() throws Exception {
+        DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
+        documentBuilderFactory.setNamespaceAware(true);
+        DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder();
+        Document document = documentBuilder.newDocument();
+        assertSame("Invalid document", document, TraxUtils.getDocument(new DOMSource(document)));
+        Element element = document.createElement("element");
+        document.appendChild(element);
+        assertSame("Invalid document", document, TraxUtils.getDocument(new DOMSource(element)));
+    }
 }