[441721] create a new URIConverter instance to avoid clearing the global
default

Bug: 441721
Signed-off-by: Cedric Brun <cedric.brun@obeo.fr>
diff --git a/plugins/org.eclipse.amalgam.discovery.core/src/org/eclipse/amalgam/discovery/core/CancellableXMIResourceImpl.java b/plugins/org.eclipse.amalgam.discovery.core/src/org/eclipse/amalgam/discovery/core/CancellableXMIResourceImpl.java
index 63dc327..25b750a 100644
--- a/plugins/org.eclipse.amalgam.discovery.core/src/org/eclipse/amalgam/discovery/core/CancellableXMIResourceImpl.java
+++ b/plugins/org.eclipse.amalgam.discovery.core/src/org/eclipse/amalgam/discovery/core/CancellableXMIResourceImpl.java
@@ -16,24 +16,25 @@
 import org.eclipse.emf.ecore.resource.impl.ExtensibleURIConverterImpl;
 import org.eclipse.emf.ecore.xmi.impl.XMIResourceImpl;
 
-public class CancellableXMIResourceImpl extends XMIResourceImpl{
+public class CancellableXMIResourceImpl extends XMIResourceImpl {
 
 	private IProgressMonitor monitor;
 
+	private URIConverter uriConverter;
+
 	public CancellableXMIResourceImpl(URI catalogURI, IProgressMonitor monitor) {
 		super(catalogURI);
 		this.monitor = monitor;
 	}
-	
+
 	@Override
 	protected URIConverter getURIConverter() {
-		URIConverter uriConverter= super.getURIConverter();
-	    if (uriConverter instanceof ExtensibleURIConverterImpl) {
-            ExtensibleURIConverterImpl extensibleURIConverterImpl = (ExtensibleURIConverterImpl) uriConverter;
-            extensibleURIConverterImpl.getURIHandlers().clear();
-            extensibleURIConverterImpl.getURIHandlers().add(new CancellableURIHandler(monitor));			            
-        }
-	    return uriConverter;
+		if (uriConverter == null) {
+			uriConverter = new ExtensibleURIConverterImpl();
+			uriConverter.getURIHandlers().clear();
+			uriConverter.getURIHandlers().add(new CancellableURIHandler(monitor));
+		}
+		return uriConverter;
 	}
 
 }