Fixes #138 - backward ccompatibility issue with JDOM 1.x DOM

JDOM 1.x managed to handle badly-built DOM documents that had implied
namespaces in place.

Author: rolfl

core/src/java/org/jdom2/input/DOMBuilder.java

@@ -342,7 +342,7 @@ private void buildTree(org.w3c.dom.Node node,
 						// Get attribute's namespace
 						Namespace attNS = null;
 						String attURI = att.getNamespaceURI(); 
-						if (attURI == null || NS_URI_DEFAULT.equals(attURI)) {
+						if (attPrefix.isEmpty() && (attURI == null || NS_URI_DEFAULT.equals(attURI))) {
 							attNS = Namespace.NO_NAMESPACE;
 						} else {
 							// various conditions can lead here.
@@ -361,7 +361,17 @@ private void buildTree(org.w3c.dom.Node node,
 								// then we re-declare it. If redeclaring it screws up
 								// other attributes in this Element, then the DOM
 								// was broken to start with.
-								attNS = Namespace.getNamespace(attPrefix, attURI);
+								if (attURI == null) {
+									// this can happen when the DOM is created
+									// without being namespace aware. we have a
+									// prefix, but the URI is not embedded in
+									// the Attribute itself. It must be declared
+									// on the element somewhere....
+									// https://github.com/hunterhacker/jdom/issues/138
+									attNS = element.getNamespace(attPrefix);
+								} else {
+									attNS = Namespace.getNamespace(attPrefix, attURI);
+								}
 							} else {
 								// OK, no prefix.
 								// must be a defaulted value from an XSD.

test/src/java/org/jdom2/test/cases/input/TestDOMBuilder.java

@@ -8,12 +8,15 @@
 import java.io.CharArrayWriter;
 import java.io.IOException;
 
-import org.junit.Test;
+import javax.xml.parsers.DocumentBuilderFactory;
 
+import org.junit.Test;
+import org.jdom2.Attribute;
 import org.jdom2.DefaultJDOMFactory;
 import org.jdom2.DocType;
 import org.jdom2.Document;
 import org.jdom2.Element;
+import org.jdom2.Namespace;
 import org.jdom2.input.DOMBuilder;
 import org.jdom2.input.SAXBuilder;
 import org.jdom2.input.sax.XMLReaders;
@@ -71,6 +74,32 @@ public void testXSDDocument() {
 		checkDOM("/xsdcomplex/input.xml", true);
 	}
 
+	@Test
+	public void testNoNamespaceDOM() throws Exception {
+		// https://github.com/hunterhacker/jdom/issues/138
+		DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
+		org.w3c.dom.Document doc = dbFactory.newDocumentBuilder().newDocument();
+		doc.setXmlVersion("1.0");
+
+		org.w3c.dom.Element root = doc.createElement("Document");
+
+		root.setAttribute("xmlns", "urn:iso:foo");
+		root.setAttribute("xmlns:xsi", "http://www.w3.org/2001/XMLSchema-instance");
+		root.setAttribute("xsi:schemaLocation", "urn:iso:foo bar.xsd");
+		doc.appendChild(root);
+
+		// The above is a badly-formed DOM document without the correct
+		// namespaceing. The second attribute should use root.setAttributeNS
+		DOMBuilder dbuilder = new DOMBuilder();
+		Document jdoc = dbuilder.build(doc);
+
+		Namespace xsi = Namespace.getNamespace("xsi", "http://www.w3.org/2001/XMLSchema-instance");
+		Attribute att = jdoc.getRootElement().getAttribute("schemaLocation", xsi);
+		assertTrue(att != null);
+		assertTrue("xsi".equals(att.getNamespacePrefix()));
+
+	}
+	
 	private void checkDOM(String resname, boolean xsdvalidate) {
 		try {
 			org.w3c.dom.Document domdoc = HelpTestDOMBuilder.getDocument(resname, xsdvalidate);