[157419] [Editor] Add Extension Components Dialog chokes when a category has invalid file location

bundles/org.eclipse.wst.xsd.ui/src-common/org/eclipse/wst/xsd/ui/internal/common/properties/sections/appinfo/AddExtensionsComponentDialog.java

diff --git a/bundles/org.eclipse.wst.xsd.ui/src-common/org/eclipse/wst/xsd/ui/internal/common/properties/sections/appinfo/AddExtensionsComponentDialog.java b/bundles/org.eclipse.wst.xsd.ui/src-common/org/eclipse/wst/xsd/ui/internal/common/properties/sections/appinfo/AddExtensionsComponentDialog.java
index 2228b43..05075e0 100644
--- a/bundles/org.eclipse.wst.xsd.ui/src-common/org/eclipse/wst/xsd/ui/internal/common/properties/sections/appinfo/AddExtensionsComponentDialog.java
+++ b/bundles/org.eclipse.wst.xsd.ui/src-common/org/eclipse/wst/xsd/ui/internal/common/properties/sections/appinfo/AddExtensionsComponentDialog.java
@@ -231,6 +231,11 @@
 		SpecificationForExtensionsSchema spec = 
 			(SpecificationForExtensionsSchema) categories[i].getData();
 		XSDSchema schema = getASISchemaModel(spec);
+		
+		if (schema == null)
+		{
+			continue;
+		}
 
 		List components = buildInput(schema);
 		specToComponentsList.put(spec, components);
@@ -444,9 +449,16 @@
 	  if (xsdSchema == null){
 		  MessageBox errDialog = new MessageBox(getShell(), SWT.ICON_ERROR);
 		  errDialog.setText(Messages._UI_ERROR_INVALID_CATEGORY);
-		  errDialog.setMessage(Messages._UI_ERROR_FILE_CANNOT_BE_PARSED
-				  + "\n" + Messages._UI_ERROR_VALIDATE_THE_FILE);  //$NON-NLS-1$
+		  // TODO (trung) I was forced to use a String in Messages to make the error clearer
+		  // When we are back to development phase, use another string: "Extension Category: "
+		  // not "Extension Categories:" + " " like we are using here
+		  errDialog.setMessage(Messages._UI_LABEL_EXTENSION_CATEGORIES + " " + spec.getDisplayName() //$NON-NLS-1$
+				  + "\n"   //$NON-NLS-1$
+				  + Messages._UI_ERROR_FILE_CANNOT_BE_PARSED
+				  + "\n" + Messages._UI_ERROR_VALIDATE_THE_FILE);   //$NON-NLS-1$
 		  errDialog.open();
+		  
+		  elementTableViewer.setInput(new ArrayList(0));
 		  return;
 	  }
 	  
@@ -534,7 +546,7 @@
 	
 	String currentValue = prefStore.getString(ExtensionsSchemasRegistry.USER_ADDED_EXT_SCHEMAS);
 	String specDesc = "  " + "\t" + schemaSpec.getDisplayName() + "\t"+
-		"\t" + schemaSpec.getNamespaceURI() + "\t" + schemaSpec.getLocation() + "\t" +
+		schemaSpec.getNamespaceURI() + "\t" + schemaSpec.getLocation() + "\t" +
 		schemaSpec.isDefautSchema() + "\t" + schemaSpec.getSourceHint() + "\t" +
 		schemaSpec.isFromCatalog();
 	currentValue += specDesc + "\n";
@@ -562,7 +574,7 @@
 	  if ( dName.equals(displayName ) )
 	  {
 		oneSpecDesc = "  " + "\t" + newSpec.getDisplayName() + "\t"+
-			"\t" + newSpec.getNamespaceURI() + "\t" + newSpec.getLocation() + "\t" +
+			newSpec.getNamespaceURI() + "\t" + newSpec.getLocation() + "\t" +
 			newSpec.isDefautSchema() + "\t" + newSpec.getSourceHint() + "\t" +
 			newSpec.isFromCatalog();		  
 	  }