added overridable method to control visibility on datatable clickable icon column

src/main/java/se/su/dsv/scipro/datatables/ClickableIconColumn.java

@@ -39,6 +39,14 @@ public abstract class ClickableIconColumn<T> extends AbstractColumn<T> {
 
     protected abstract void onClick(IModel<T> clicked, AjaxRequestTarget target);
 
+    /**
+     * Override this if you want to customize the visibility of the icon. 
+     * e.g. the case where you wnat some specific rows editable based on certain conditions.
+     */
+    public boolean shouldBeVisible(IModel<T> rowModel) {
+    	return true;
+    }
+    
     private class LinkPanel extends Panel {
         public LinkPanel(String id, IModel<T> rowModel, IModel<?>
                 labelModel, String iconString) {
@@ -52,6 +60,7 @@ public abstract class ClickableIconColumn<T> extends AbstractColumn<T> {
             };
             add(link);
             link.add(new ImageObject("deleteicon", ImageObject.SIXTEEN + iconString));
+            link.setVisible(shouldBeVisible(rowModel));
         }
     }
 }