diff -r e854d8cb376c -r 186c4121c7b3 Entity/DocumentRepository.php
--- a/Entity/DocumentRepository.php	Mon Nov 28 15:58:34 2011 +0100
+++ b/Entity/DocumentRepository.php	Tue Dec 06 14:53:12 2011 +0100
@@ -365,5 +365,28 @@
         
         return $res;
     }
+    
+    /**
+     * Copy the tahg lst from one document instance to another
+     * @param IRI\Bundle\WikitagBundle\Model\DocumentInterface $src_doc
+     * @param IRI\Bundle\WikitagBundle\Model\DocumentInterface $tgt_doc
+     */
+    public function copyTags($src_doc, $tgt_doc)
+    {
+        //remove the previous tags
+        foreach ($tgt_doc->getTags() as $doctag) {
+            $this->getEntityManager()->remove($doctag);
+        }
+        
+        // add the new ones
+        foreach ($src_doc->getTags() as $doctag) {
+            $new_doctag = clone $doctag;
+            $new_doctag->setDocument($tgt_doc);
+            $this->getEntityManager()->persist($new_doctag);
+        }
+        
+        $tgt_doc->setManualOrder(false);
+        $this->getEntityManager()->persist($tgt_doc);
+    }
         
 }
\ No newline at end of file