diff --git a/src/main/java/org/gcube/socialnetworking/social_data_indexing_common/utils/SearchableFields.java b/src/main/java/org/gcube/socialnetworking/social_data_indexing_common/utils/SearchableFields.java
index 810a273..65ba7a2 100644
--- a/src/main/java/org/gcube/socialnetworking/social_data_indexing_common/utils/SearchableFields.java
+++ b/src/main/java/org/gcube/socialnetworking/social_data_indexing_common/utils/SearchableFields.java
@@ -4,12 +4,23 @@ package org.gcube.socialnetworking.social_data_indexing_common.utils;
  * The fields of the documents which are searchable. 
  * @author Costantino Perciante at ISTI-CNR (costantino.perciante@isti.cnr.it)
  */
-public class SearchableFields {
-	public static final String POST_TEXT = "feed.description";
-	public static final String COMMENT_TEXT = "comments.text";
-	public static final String PREVIEW_DESCRIPTION = "feed.linkTitle";
-	public static final String POST_AUTHOR = "feed.fullName";
-	public static final String POST_VRE_ID = "feed.vreid";
-	public static final String COMMENT_AUTHOR = "comments.fullName";
-	public static final String ATTACHMENT_NAME = "attachments.name";
+public enum SearchableFields {
+	POST_TEXT("feed.description"),
+	COMMENT_TEXT("comments.text"),
+	PREVIEW_DESCRIPTION("feed.linkTitle"),
+	POST_AUTHOR("feed.fullName"),
+	POST_VRE_ID("feed.vreid"),
+	COMMENT_AUTHOR("comments.fullName"),
+	ATTACHMENT_NAME("attachments.name");
+
+	String name;
+
+	SearchableFields(String name){
+		this.name = name;
+	}
+
+	@Override
+	public String toString() {
+		return name;
+	}
 }