Fixing public link as long URL for public folder

src/main/java/org/gcube/portlets/user/workspace/client/view/windows/DialogShareableLink.java

@@ -244,7 +244,7 @@ public class DialogShareableLink extends Composite {
 			
 			@Override
 			public void onClick(ClickEvent event) {
-				if(loadedPublicLink!=null) {
+				if(loadedPublicLink!=null && loadedPublicLink.getCompleteURL()!=null) {
 					showPublicLongLinkButton.setVisible(false);
 					cgPublicLongLink.setVisible(true);
 					textPublicLongLink.setText(loadedPublicLink.getCompleteURL());
@@ -591,6 +591,7 @@ public class DialogShareableLink extends Composite {
 
 			@Override
 			public void onFailure(Throwable caught) {
+				loadedPublicLink = null;
 				if (caught instanceof SessionExpiredException) {
 					GWT.log("Session expired");
 					AppControllerExplorer.getEventBus().fireEvent(new SessionExpiredEvent());
@@ -749,6 +750,7 @@ public class DialogShareableLink extends Composite {
 
 				@Override
 				public void onSuccess(PublicLink publicLink) {
+					loadedPublicLink = publicLink;
 
 					if (!setIsPublic && publicLink == null) {
 						String msg = "Public Link to the folder '" + fileItem.getName() + "' removed correctly";
@@ -789,6 +791,7 @@ public class DialogShareableLink extends Composite {
 
 				@Override
 				public void onFailure(Throwable caught) {
+					loadedPublicLink = null;
 					fieldSetPublic.setVisible(false);
 					if (caught instanceof SessionExpiredException) {
 						GWT.log("Session expired");