diff --git a/src/main/java/de/craftinc/replicator/BlockPlaceListener.java b/src/main/java/de/craftinc/replicator/BlockPlaceListener.java
new file mode 100644
index 0000000..ad99301
--- /dev/null
+++ b/src/main/java/de/craftinc/replicator/BlockPlaceListener.java
@@ -0,0 +1,39 @@
+/*  Craft Inc. Replicator
+    Copyright (C) 2013  Paul Schulze, Maximilian Häckel, Moritz Kaltofen
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package de.craftinc.replicator;
+
+import org.bukkit.Location;
+import org.bukkit.event.Listener;
+import org.bukkit.event.block.BlockPlaceEvent;
+
+import java.util.ArrayList;
+
+public class BlockPlaceListener implements Listener {
+
+    public void onBlockPlaced(BlockPlaceEvent event){
+        ArrayList<Location> replicators = Replicator.getReplicators(event.getBlockPlaced().getLocation());
+        if(!replicators.isEmpty()){
+            for(Location loc:replicators){
+                Replicator rep = Replicator.getOrCreate(loc,event.getPlayer().getName());
+                if(rep!=null){
+                    event.getPlayer().sendMessage(Messages.newReplicator(rep));
+                }
+            }
+        }
+    }
+}
diff --git a/src/main/java/de/craftinc/replicator/Messages.java b/src/main/java/de/craftinc/replicator/Messages.java
index 1b84488..c7cf7f5 100644
--- a/src/main/java/de/craftinc/replicator/Messages.java
+++ b/src/main/java/de/craftinc/replicator/Messages.java
@@ -124,4 +124,6 @@ public class Messages
         }
         return sb.toString();
     }
+
+
 }
diff --git a/src/main/java/de/craftinc/replicator/Plugin.java b/src/main/java/de/craftinc/replicator/Plugin.java
index bab8642..a0fe719 100644
--- a/src/main/java/de/craftinc/replicator/Plugin.java
+++ b/src/main/java/de/craftinc/replicator/Plugin.java
@@ -27,7 +27,7 @@ public class Plugin extends JavaPlugin
     @Override
     public void onLoad()
     {
-        ConfigurationSerialization.registerClass(Replicator.class);
+        //ConfigurationSerialization.registerClass(Replicator.class);
     }
 
     @Override
diff --git a/src/main/java/de/craftinc/replicator/Replicator.java b/src/main/java/de/craftinc/replicator/Replicator.java
index e35142d..8a175ae 100644
--- a/src/main/java/de/craftinc/replicator/Replicator.java
+++ b/src/main/java/de/craftinc/replicator/Replicator.java
@@ -22,19 +22,23 @@ import org.bukkit.block.BlockFace;
 import org.bukkit.Material;
 
 import java.util.ArrayList;
+import java.util.HashMap;
 
 public class Replicator {
 
     private ArrayList<String> owners;
     private ArrayList<String> users;
+    private String name;
+    private static HashMap<Location,Replicator> allReplicators;
 
     private Location center;
 
-    public Replicator(String firstOwner, Location spawn, Location center) {
+    public Replicator(String firstOwner, Location center) {
         this.owners = new ArrayList<String>();
         this.users = new ArrayList<String>();
         this.owners.add(firstOwner);
         this.center = center;
+        name = center.getWorld()+","+center.getBlockX()+","+center.getBlockY()+","+center.getBlockZ();
     }
 
     public void addUser(String user) {
@@ -55,6 +59,33 @@ public class Replicator {
         else return false;
     }
 
+    public boolean isOwner(String player){
+        for(String owner:owners){
+            if(owner.equals(player)){
+                return true;
+            }
+        }
+        return false;
+    }
+
+    public boolean isUser(String player){
+        for(String user:users){
+            if(user.equals(player)){
+                return true;
+            }
+        }
+        return false;
+    }
+
+    public void setName(String newName){
+        this.name=newName;
+        //TODO: Save List
+    }
+
+    public String getName(){
+        return name;
+    }
+
     public static ArrayList<Location> getReplicators(Location currentBlock){
         ArrayList<Location> replicators = new ArrayList<Location>();
         ArrayList<Location> centers = getCenters(currentBlock);
@@ -76,6 +107,9 @@ public class Replicator {
 
     private static boolean isValid(Location center){
         Material[][][] pattern = getPattern(center);
+        if(pattern==null){
+            return false;
+        }
         for(int x=0;x<=2;x++){
             for(int y=0;y<=2;y++){
                 for(int z=0;z<=2;z++){
@@ -102,4 +136,49 @@ public class Replicator {
         return centers;
     }
 
+    public static Replicator getOrCreate(Location loc, String playerName) {     //Returns null, if player is not owner or user of the replicator
+        Replicator rep = allReplicators.get(loc);
+        if(rep!=null){
+            if(rep.isOwner(playerName)||rep.isUser(playerName)){
+                return allReplicators.get(loc);
+            }
+            else return null;
+        }
+        else {
+            rep = new Replicator(playerName,loc);
+            allReplicators.put(loc, rep);
+            return rep;
+        }
+    }
+
+    public static Replicator getByName(String repName, String playerName){ //Returns null, if player is not owner or user or if replicator does not exist
+        for(Replicator rep: allReplicators.values()){
+            if(rep.getName().equals(repName)){
+                if(rep.isOwner(playerName)||rep.isUser(playerName)){
+                    return rep;
+                }
+            }
+        }
+        return null;
+    }
+
+    public ArrayList<Replicator> getReplicatorsByOwner(String playerName){
+        ArrayList<Replicator> reps = new ArrayList<Replicator>();
+        for(Replicator rep: allReplicators.values()){
+            if(rep.isOwner(playerName)){
+                reps.add(rep);
+            }
+        }
+        return reps;
+    }
+
+    public ArrayList<Replicator> getReplicatorsByUser(String playerName){
+        ArrayList<Replicator> reps = new ArrayList<Replicator>();
+        for(Replicator rep: allReplicators.values()){
+            if(rep.isUser(playerName)){
+                reps.add(rep);
+            }
+        }
+        return reps;
+    }
 }