Try to fix energy overflow

* imrpove canConnectToExternal()

* needUpdateConnections

* add comments for needUpdateconnections

src/main/java/crazypants/enderio/conduit/AbstractConduit.java

@@ -84,7 +84,17 @@ public abstract class AbstractConduit implements IConduit {
 
     protected boolean connectionsDirty = true;
 
-    protected boolean needUpdateConnections = false;
+    /**
+     * This shows if the currently running connection update should not finish with settings connectionsDirty to false.
+     * If this is true, it will trigger a reconnection on the next Tick.
+     * <p>
+     * Use the method needUpdateConnections() instead of setting this to true.
+     * 
+     * @see needUpdateConnections()
+     */
+    private boolean needUpdateConnections = false;
+
+    private boolean isUpdatingConnections = false;
 
     protected AbstractConduit() {}
 
@@ -436,10 +446,13 @@ public abstract class AbstractConduit implements IConduit {
     }
 
     private void updateConnections() {
-        if (!connectionsDirty) {
+        if (!connectionsDirty && !needUpdateConnections) {
             return;
         }
 
+        isUpdatingConnections = true;
+        needUpdateConnections = false;
+
         boolean externalConnectionsChanged = false;
         List<ForgeDirection> copy = new ArrayList<ForgeDirection>(externalConnections);
         // remove any no longer valid connections
@@ -463,15 +476,22 @@ public abstract class AbstractConduit implements IConduit {
             connectionsChanged();
         }
 
-        if (needUpdateConnections) {
-            needUpdateConnections = false;
-        } else {
-            connectionsDirty = false;
-        }
+        connectionsDirty = false;
+        isUpdatingConnections = false;
     }
 
+    /**
+     * This method prevents connection update from getting completed successfully by not settings connectionsDirty to
+     * false. This will trigger an connection update at the next Tick.
+     * <p>
+     * Only use this while executing updateConnections().
+     * <p>
+     * See this PR for more info: https://github.com/GTNewHorizons/EnderIO/pull/111
+     */
     protected void needUpdateConnections() {
-        needUpdateConnections = true;
+        if (isUpdatingConnections) {
+            needUpdateConnections = true;
+        }
     }
 
     @Override

src/main/java/crazypants/enderio/conduit/me/MEConduit.java

@@ -175,6 +175,7 @@ public class MEConduit extends AbstractConduit implements IMEConduit {
                     node = part.getGridNode();
                 }
                 if (node == null) {
+                    // The GridNode has not been initialized yet, let's try on the next Tick.
                     needUpdateConnections();
                 }
             }

src/main/java/crazypants/enderio/item/ItemMagnet.java

@@ -131,6 +131,10 @@ public class ItemMagnet extends ItemEnergyContainer implements IResourceTooltipP
 
     @Override
     public int receiveEnergy(ItemStack container, int maxReceive, boolean simulate) {
+        if (maxReceive < 0) {
+            return 0;
+        }
+
         int res = super.receiveEnergy(container, maxReceive, simulate);
         if (res != 0 && !simulate) {
             updateDamage(container);
@@ -148,6 +152,10 @@ public class ItemMagnet extends ItemEnergyContainer implements IResourceTooltipP
     }
 
     public int extractEnergyInternal(ItemStack container, int maxExtract, boolean simulate) {
+        if (maxExtract < 0) {
+            return 0;
+        }
+
         int res = super.extractEnergy(container, maxExtract, simulate);
         if (res != 0 && !simulate) {
             updateDamage(container);

src/main/java/crazypants/enderio/teleport/ItemTeleportStaff.java

@@ -67,6 +67,12 @@ public class ItemTeleportStaff extends ItemTravelStaff {
         return equipped;
     }
 
+    @Override
+    public int receiveEnergy(ItemStack container, int maxReceive, boolean simulate) {
+        // Don't allow receiving energy, since we have infinite energy.
+        return 0;
+    }
+
     @Override
     public int extractEnergy(ItemStack container, int maxExtract, boolean simulate) {
         // Don't allow extracting energy.

src/main/java/crazypants/enderio/teleport/ItemTravelStaff.java

@@ -103,6 +103,10 @@ public class ItemTravelStaff extends ItemEnergyContainer implements IItemOfTrave
 
     @Override
     public int receiveEnergy(ItemStack container, int maxReceive, boolean simulate) {
+        if (maxReceive < 0) {
+            return 0;
+        }
+
         int res = super.receiveEnergy(container, maxReceive, simulate);
         if (res != 0 && !simulate) {
             updateDamage(container);
@@ -112,6 +116,10 @@ public class ItemTravelStaff extends ItemEnergyContainer implements IItemOfTrave
 
     @Override
     public int extractEnergy(ItemStack container, int maxExtract, boolean simulate) {
+        if (maxExtract < 0) {
+            return 0;
+        }
+
         int res = super.extractEnergy(container, maxExtract, simulate);
         if (res != 0 && !simulate) {
             updateDamage(container);