--- a/src/main/java/de/mpiwg/itgroup/annotations/Actor.java	Thu Jul 12 12:54:46 2012 +0200
+++ b/src/main/java/de/mpiwg/itgroup/annotations/Actor.java	Thu Jul 12 17:01:32 2012 +0200
@@ -3,42 +3,24 @@
  */
 package de.mpiwg.itgroup.annotations;
 
+import de.mpiwg.itgroup.annotations.old.NS;
+
 /**
  * @author casties
  *
  */
-public class Actor {
+public abstract class Actor {
 
-    public boolean isGroup;
     public String uri;
     public String name;
+    public String id;
     
     /**
-     * @param isGroup
-     * @param id
-     * @param uri
-     * @param name
+     * @return if this Actor is a Group
      */
-    public Actor(boolean isGroup, String uri, String name) {
-        super();
-        this.isGroup = isGroup;
-        this.uri = uri;
-        this.name = name;
-    }
+    public abstract boolean isGroup();
     
     /**
-     * @return the isGroup
-     */
-    public boolean isGroup() {
-        return isGroup;
-    }
-    /**
-     * @param isGroup the isGroup to set
-     */
-    public void setGroup(boolean isGroup) {
-        this.isGroup = isGroup;
-    }
-    /**
      * @return the uri
      */
     public String getUri() {
@@ -62,4 +44,62 @@
     public void setName(String name) {
         this.name = name;
     }
+
+    /**
+     * @return the id
+     */
+    public String getId() {
+        return id;
+    }
+    
+    /**
+     * Returns id as a String starting with "group:" for groups.
+     * 
+     * @return
+     */
+    public abstract String getIdString();
+    
+    /**
+     * @param id the id to set
+     */
+    public void setId(String id) {
+        this.id = id;
+    }
+    
+    /**
+     * Returns a short id from an uri.
+     * 
+     * @param uri
+     * @return
+     */
+    public static String getIdFromUri(String uri, boolean isGroup) {
+        String id = null;
+        String prefix = NS.MPIWG_PERSONS_URL;
+        if (isGroup) {
+            prefix = NS.MPIWG_GROUPS_URL;
+        }
+        if (uri != null && uri.startsWith(prefix)) {
+            id = uri.replace(prefix, "");
+        }
+        return id;
+    }
+
+    /**
+     * Returns an uri from a short id.
+     * 
+     * @param id
+     * @return
+     */
+    public static String getUriFromId(String id, boolean isGroup) {
+        String uri = null;
+        String prefix = NS.MPIWG_PERSONS_URL;
+        if (isGroup) {
+            prefix = NS.MPIWG_GROUPS_URL;
+        }
+        if (id != null && ! id.startsWith("http://")) {
+            uri = prefix + id; 
+        }
+        return uri;
+    }
+
 }