--- ../work/decompile-8eb82bde//net/minecraft/server/TileEntityBeacon.java	2014-12-27 14:58:26.269254675 +0000
+++ src/main/java/net/minecraft/server/TileEntityBeacon.java	2014-12-27 14:58:26.269254675 +0000
@@ -5,6 +5,11 @@
 import java.util.Iterator;
 import java.util.List;
 
+// CraftBukkit start
+import org.bukkit.craftbukkit.entity.CraftHumanEntity;
+import org.bukkit.entity.HumanEntity;
+// CraftBukkit end
+
 public class TileEntityBeacon extends TileEntityContainer implements IUpdatePlayerListBox, IInventory {
 
     public static final MobEffectList[][] a = new MobEffectList[][] { { MobEffectList.FASTER_MOVEMENT, MobEffectList.FASTER_DIG}, { MobEffectList.RESISTANCE, MobEffectList.JUMP}, { MobEffectList.INCREASE_DAMAGE}, { MobEffectList.REGENERATION}};
@@ -15,6 +20,30 @@
     private int l;
     private ItemStack inventorySlot;
     private String n;
+    // CraftBukkit start - add fields and methods
+    public List<HumanEntity> transaction = new java.util.ArrayList<HumanEntity>();
+    private int maxStack = MAX_STACK;
+
+    public ItemStack[] getContents() {
+        return new ItemStack[] { this.inventorySlot };
+    }
+
+    public void onOpen(CraftHumanEntity who) {
+        transaction.add(who);
+    }
+
+    public void onClose(CraftHumanEntity who) {
+        transaction.remove(who);
+    }
+
+    public List<HumanEntity> getViewers() {
+        return transaction;
+    }
+
+    public void setMaxStackSize(int size) {
+        maxStack = size;
+    }
+    // CraftBukkit end
 
     public TileEntityBeacon() {}
 
@@ -169,8 +198,8 @@
 
     public void a(NBTTagCompound nbttagcompound) {
         super.a(nbttagcompound);
-        this.k = nbttagcompound.getInt("Primary");
-        this.l = nbttagcompound.getInt("Secondary");
+        this.k = validateEffect(nbttagcompound.getInt("Primary")); // CraftBukkit
+        this.l = validateEffect(nbttagcompound.getInt("Secondary")); // CraftBukkit
         this.j = nbttagcompound.getInt("Levels");
     }
 
@@ -182,7 +211,7 @@
     }
 
     public int getSize() {
-        return 1;
+        return maxStack; // CraftBukkit
     }
 
     public ItemStack getItem(int i) {
@@ -282,11 +311,11 @@
             break;
 
         case 1:
-            this.k = j;
+            this.k = validateEffect(j); // CraftBukkit
             break;
 
         case 2:
-            this.l = j;
+            this.l = validateEffect(j); // CraftBukkit
         }
 
     }
@@ -307,4 +336,23 @@
             return super.c(i, j);
         }
     }
+
+    // CraftBukkit start
+    public int validateEffect(int i) {
+        i = i < 0 || i >= MobEffectList.byId.length || MobEffectList.byId[i] == null ? 0 : i;
+        switch (i) {
+            case 1: // MobEffectList.FASTER_MOVEMENT.id
+            case 3: // MobEffectList.FASTER_DIG.id
+            case 11: // MobEffectList.RESISTANCE.id
+            case 8: // MobEffectList.JUMP.id
+            case 5: // MobEffectList.INCREASE_DAMAGE.id
+            case 10: // MobEffectList.REGENERATION.id
+                break;
+            default:                
+                i = 0;
+                break;
+        }
+        return i;
+    }
+    // CraftBukkit end
 }