Fix subtle bugs, not finished yet in a long shot

src/main/java/com/raoulvdberge/refinedstorage/block/BlockBase.java

@@ -107,7 +107,7 @@ public abstract class BlockBase extends Block {
             IItemHandler handler = ((TileBase) tile).getDrops();
 
             for (int i = 0; i < handler.getSlots(); ++i) {
-                if (handler.getStackInSlot(i) != null) {
+                if (!handler.getStackInSlot(i).isEmpty()) {
                     InventoryHelper.spawnItemStack(world, pos.getX(), pos.getY(), pos.getZ(), handler.getStackInSlot(i));
                 }
             }

src/main/java/com/raoulvdberge/refinedstorage/block/BlockCable.java

@@ -198,4 +198,8 @@ public class BlockCable extends BlockNode {
     public BlockRenderLayer getBlockLayer() {
         return BlockRenderLayer.CUTOUT;
     }
+
+    public EnumPlacementType getPlacementType() {
+        return null;
+    }
 }

src/main/java/com/raoulvdberge/refinedstorage/block/BlockController.java

@@ -63,10 +63,8 @@ public class BlockController extends BlockBase {
 
     @Override
     public IBlockState getActualState(IBlockState state, IBlockAccess world, BlockPos pos) {
-        TileController controller = (TileController) world.getTileEntity(pos);
-
         return super.getActualState(state, world, pos)
-            .withProperty(ENERGY, controller.getEnergyScaledForDisplay());
+            .withProperty(ENERGY, ((TileController) world.getTileEntity(pos)).getEnergyScaledForDisplay());
     }
 
     @Override

src/main/java/com/raoulvdberge/refinedstorage/container/ContainerBase.java

@@ -57,8 +57,8 @@ public abstract class ContainerBase extends Container {
     public ItemStack slotClick(int id, int dragType, ClickType clickType, EntityPlayer player) {
         Slot slot = id >= 0 ? getSlot(id) : null;
 
-        if (slot instanceof SlotSpecimen) {
+        if (slot instanceof SlotFilter) {
-            if (((SlotSpecimen) slot).isWithSize()) {
+            if (((SlotFilter) slot).isWithSize()) {
                 if (clickType == ClickType.QUICK_MOVE) {
                     slot.putStack(ItemStack.EMPTY);
                 } else if (!player.inventory.getItemStack().isEmpty()) {
@@ -83,7 +83,7 @@ public abstract class ContainerBase extends Container {
             }
 
             return player.inventory.getItemStack();
-        } else if (slot instanceof SlotSpecimenLegacy) {
+        } else if (slot instanceof SlotFilterLegacy) {
             if (player.inventory.getItemStack().isEmpty()) {
                 slot.putStack(ItemStack.EMPTY);
             } else if (slot.isItemValid(player.inventory.getItemStack())) {
@@ -92,7 +92,7 @@ public abstract class ContainerBase extends Container {
 
             return player.inventory.getItemStack();
         } else if (slot instanceof SlotDisabled) {
-            return null;
+            return ItemStack.EMPTY;
         }
 
         return super.slotClick(id, dragType, clickType, player);
@@ -117,21 +117,21 @@ public abstract class ContainerBase extends Container {
                 slot.putStack(ItemHandlerHelper.copyStackWithSize(stack, 1));
                 slot.onSlotChanged();
 
-                return null;
+                return ItemStack.EMPTY;
             }
         }
 
-        return null;
+        return ItemStack.EMPTY;
     }
 
     private ItemStack getStackFromSlot(Slot slot) {
         ItemStack stackInSlot = slot.getStack();
 
-        if (stackInSlot == null) {
+        if (stackInSlot.isEmpty()) {
-            if (slot instanceof SlotSpecimenFluid) {
+            if (slot instanceof SlotFilterFluid) {
-                stackInSlot = ((SlotSpecimenFluid) slot).getRealStack();
+                stackInSlot = ((SlotFilterFluid) slot).getRealStack();
-            } else if (slot instanceof SlotSpecimenType) {
+            } else if (slot instanceof SlotFilterType) {
-                stackInSlot = ((SlotSpecimenType) slot).getRealStack();
+                stackInSlot = ((SlotFilterType) slot).getRealStack();
             }
         }
 

src/main/java/com/raoulvdberge/refinedstorage/container/ContainerConstructor.java

@@ -1,6 +1,6 @@
 package com.raoulvdberge.refinedstorage.container;
 
-import com.raoulvdberge.refinedstorage.container.slot.SlotSpecimenType;
+import com.raoulvdberge.refinedstorage.container.slot.SlotFilterType;
 import com.raoulvdberge.refinedstorage.tile.TileConstructor;
 import net.minecraft.entity.player.EntityPlayer;
 import net.minecraft.inventory.Slot;
@@ -15,30 +15,30 @@ public class ContainerConstructor extends ContainerBase {
             addSlotToContainer(new SlotItemHandler(constructor.getUpgrades(), i, 187, 6 + (i * 18)));
         }
 
-        addSlotToContainer(new SlotSpecimenType(constructor, 0, 80, 20));
+        addSlotToContainer(new SlotFilterType(constructor, 0, 80, 20));
 
         addPlayerInventory(8, 55);
     }
 
     @Override
     public ItemStack transferStackInSlot(EntityPlayer player, int index) {
-        ItemStack stack = null;
+        ItemStack stack = ItemStack.EMPTY;
 
         Slot slot = getSlot(index);
 
-        if (slot != null && slot.getHasStack()) {
+        if (slot.getHasStack()) {
             stack = slot.getStack();
 
             if (index < 4) {
                 if (!mergeItemStack(stack, 4, inventorySlots.size(), false)) {
-                    return null;
+                    return ItemStack.EMPTY;
                 }
             } else if (!mergeItemStack(stack, 0, 4, false)) {
                 return mergeItemStackToSpecimen(stack, 4, 4 + 1);
             }
 
             if (stack.getCount() == 0) {
-                slot.putStack(null);
+                slot.putStack(ItemStack.EMPTY);
             } else {
                 slot.onSlotChanged();
             }

src/main/java/com/raoulvdberge/refinedstorage/container/ContainerCrafter.java

@@ -23,23 +23,23 @@ public class ContainerCrafter extends ContainerBase {
 
     @Override
     public ItemStack transferStackInSlot(EntityPlayer player, int index) {
-        ItemStack stack = null;
+        ItemStack stack = ItemStack.EMPTY;
 
         Slot slot = getSlot(index);
 
-        if (slot != null && slot.getHasStack()) {
+        if (slot.getHasStack()) {
             stack = slot.getStack();
 
             if (index < 9 + 4) {
                 if (!mergeItemStack(stack, 9 + 4, inventorySlots.size(), false)) {
-                    return null;
+                    return ItemStack.EMPTY;
                 }
             } else if (!mergeItemStack(stack, 0, 9 + 4, false)) {
-                return null;
+                return ItemStack.EMPTY;
             }
 
             if (stack.getCount() == 0) {
-                slot.putStack(null);
+                slot.putStack(ItemStack.EMPTY);
             } else {
                 slot.onSlotChanged();
             }

src/main/java/com/raoulvdberge/refinedstorage/container/ContainerDestructor.java

@@ -1,6 +1,6 @@
 package com.raoulvdberge.refinedstorage.container;
 
-import com.raoulvdberge.refinedstorage.container.slot.SlotSpecimenType;
+import com.raoulvdberge.refinedstorage.container.slot.SlotFilterType;
 import com.raoulvdberge.refinedstorage.tile.TileDestructor;
 import net.minecraft.entity.player.EntityPlayer;
 import net.minecraft.inventory.Slot;
@@ -16,7 +16,7 @@ public class ContainerDestructor extends ContainerBase {
         }
 
         for (int i = 0; i < 9; ++i) {
-            addSlotToContainer(new SlotSpecimenType(destructor, i, 8 + (18 * i), 20));
+            addSlotToContainer(new SlotFilterType(destructor, i, 8 + (18 * i), 20));
         }
 
         addPlayerInventory(8, 55);
@@ -24,23 +24,23 @@ public class ContainerDestructor extends ContainerBase {
 
     @Override
     public ItemStack transferStackInSlot(EntityPlayer player, int index) {
-        ItemStack stack = null;
+        ItemStack stack = ItemStack.EMPTY;
 
         Slot slot = getSlot(index);
 
-        if (slot != null && slot.getHasStack()) {
+        if (slot.getHasStack()) {
             stack = slot.getStack();
 
             if (index < 4) {
                 if (!mergeItemStack(stack, 4 + 9, inventorySlots.size(), false)) {
-                    return null;
+                    return ItemStack.EMPTY;
                 }
             } else if (!mergeItemStack(stack, 0, 4, false)) {
                 return mergeItemStackToSpecimen(stack, 4, 4 + 9);
             }
 
             if (stack.getCount() == 0) {
-                slot.putStack(null);
+                slot.putStack(ItemStack.EMPTY);
             } else {
                 slot.onSlotChanged();
             }

src/main/java/com/raoulvdberge/refinedstorage/container/ContainerDetector.java

@@ -1,6 +1,6 @@
 package com.raoulvdberge.refinedstorage.container;
 
-import com.raoulvdberge.refinedstorage.container.slot.SlotSpecimenType;
+import com.raoulvdberge.refinedstorage.container.slot.SlotFilterType;
 import com.raoulvdberge.refinedstorage.tile.TileDetector;
 import net.minecraft.entity.player.EntityPlayer;
 import net.minecraft.inventory.Slot;
@@ -10,7 +10,7 @@ public class ContainerDetector extends ContainerBase {
     public ContainerDetector(TileDetector detector, EntityPlayer player) {
         super(detector, player);
 
-        addSlotToContainer(new SlotSpecimenType(detector, 0, 107, 20));
+        addSlotToContainer(new SlotFilterType(detector, 0, 107, 20));
 
         addPlayerInventory(8, 55);
     }
@@ -19,7 +19,7 @@ public class ContainerDetector extends ContainerBase {
     public ItemStack transferStackInSlot(EntityPlayer player, int index) {
         Slot slot = getSlot(index);
 
-        if (slot != null && slot.getHasStack() && index > 0) {
+        if (slot.getHasStack() && index > 0) {
             return mergeItemStackToSpecimen(slot.getStack(), 0, 1);
         }
 

src/main/java/com/raoulvdberge/refinedstorage/container/ContainerDiskDrive.java

@@ -1,6 +1,6 @@
 package com.raoulvdberge.refinedstorage.container;
 
-import com.raoulvdberge.refinedstorage.container.slot.SlotSpecimenType;
+import com.raoulvdberge.refinedstorage.container.slot.SlotFilterType;
 import com.raoulvdberge.refinedstorage.tile.TileDiskDrive;
 import net.minecraft.entity.player.EntityPlayer;
 import net.minecraft.inventory.Slot;
@@ -19,7 +19,7 @@ public class ContainerDiskDrive extends ContainerBase {
         }
 
         for (int i = 0; i < 9; ++i) {
-            addSlotToContainer(new SlotSpecimenType(drive, i, 8 + (18 * i), 20));
+            addSlotToContainer(new SlotFilterType(drive, i, 8 + (18 * i), 20));
         }
 
         addPlayerInventory(8, 141);
@@ -27,23 +27,23 @@ public class ContainerDiskDrive extends ContainerBase {
 
     @Override
     public ItemStack transferStackInSlot(EntityPlayer player, int index) {
-        ItemStack stack = null;
+        ItemStack stack = ItemStack.EMPTY;
 
         Slot slot = getSlot(index);
 
-        if (slot != null && slot.getHasStack()) {
+        if (slot.getHasStack()) {
             stack = slot.getStack();
 
             if (index < 8) {
                 if (!mergeItemStack(stack, 8 + 9, inventorySlots.size(), false)) {
-                    return null;
+                    return ItemStack.EMPTY;
                 }
             } else if (!mergeItemStack(stack, 0, 8, false)) {
                 return mergeItemStackToSpecimen(stack, 8, 8 + 9);
             }
 
             if (stack.getCount() == 0) {
-                slot.putStack(null);
+                slot.putStack(ItemStack.EMPTY);
             } else {
                 slot.onSlotChanged();
             }

src/main/java/com/raoulvdberge/refinedstorage/container/ContainerDiskManipulator.java

@@ -1,6 +1,6 @@
 package com.raoulvdberge.refinedstorage.container;
 
-import com.raoulvdberge.refinedstorage.container.slot.SlotSpecimenType;
+import com.raoulvdberge.refinedstorage.container.slot.SlotFilterType;
 import com.raoulvdberge.refinedstorage.tile.TileDiskManipulator;
 import net.minecraft.entity.player.EntityPlayer;
 import net.minecraft.inventory.Slot;
@@ -24,7 +24,7 @@ public class ContainerDiskManipulator extends ContainerBase {
         }
 
         for (int i = 0; i < 9; ++i) {
-            addSlotToContainer(new SlotSpecimenType(manipulator, i, 8 + (18 * i), 20));
+            addSlotToContainer(new SlotFilterType(manipulator, i, 8 + (18 * i), 20));
         }
 
         addPlayerInventory(8, 129);
@@ -32,23 +32,23 @@ public class ContainerDiskManipulator extends ContainerBase {
 
     @Override
     public ItemStack transferStackInSlot(EntityPlayer player, int index) {
-        ItemStack stack = null;
+        ItemStack stack = ItemStack.EMPTY;
 
         Slot slot = getSlot(index);
 
-        if (slot != null && slot.getHasStack()) {
+        if (slot.getHasStack()) {
             stack = slot.getStack();
 
             if (index < 4 + 6) {
                 if (!mergeItemStack(stack, 4 + 6 + 9, inventorySlots.size(), false)) {
-                    return null;
+                    return ItemStack.EMPTY;
                 }
             } else if (!mergeItemStack(stack, 0, 4 + 3, false)) {
                 return mergeItemStackToSpecimen(stack, 4 + 6, 4 + 6 + 9);
             }
 
             if (stack.getCount() == 0) {
-                slot.putStack(null);
+                slot.putStack(ItemStack.EMPTY);
             } else {
                 slot.onSlotChanged();
             }

src/main/java/com/raoulvdberge/refinedstorage/container/ContainerExporter.java

@@ -1,6 +1,6 @@
 package com.raoulvdberge.refinedstorage.container;
 
-import com.raoulvdberge.refinedstorage.container.slot.SlotSpecimenType;
+import com.raoulvdberge.refinedstorage.container.slot.SlotFilterType;
 import com.raoulvdberge.refinedstorage.tile.TileExporter;
 import net.minecraft.entity.player.EntityPlayer;
 import net.minecraft.inventory.Slot;
@@ -16,7 +16,7 @@ public class ContainerExporter extends ContainerBase {
         }
 
         for (int i = 0; i < 9; ++i) {
-            addSlotToContainer(new SlotSpecimenType(exporter, i, 8 + (18 * i), 20));
+            addSlotToContainer(new SlotFilterType(exporter, i, 8 + (18 * i), 20));
         }
 
         addPlayerInventory(8, 55);
@@ -24,23 +24,23 @@ public class ContainerExporter extends ContainerBase {
 
     @Override
     public ItemStack transferStackInSlot(EntityPlayer player, int index) {
-        ItemStack stack = null;
+        ItemStack stack = ItemStack.EMPTY;
 
         Slot slot = getSlot(index);
 
-        if (slot != null && slot.getHasStack()) {
+        if (slot.getHasStack()) {
             stack = slot.getStack();
 
             if (index < 4) {
                 if (!mergeItemStack(stack, 4 + 9, inventorySlots.size(), false)) {
-                    return null;
+                    return ItemStack.EMPTY;
                 }
             } else if (!mergeItemStack(stack, 0, 4, false)) {
                 return mergeItemStackToSpecimen(stack, 4, 4 + 9);
             }
 
             if (stack.getCount() == 0) {
-                slot.putStack(null);
+                slot.putStack(ItemStack.EMPTY);
             } else {
                 slot.onSlotChanged();
             }

src/main/java/com/raoulvdberge/refinedstorage/container/ContainerExternalStorage.java

@@ -1,6 +1,6 @@
 package com.raoulvdberge.refinedstorage.container;
 
-import com.raoulvdberge.refinedstorage.container.slot.SlotSpecimenType;
+import com.raoulvdberge.refinedstorage.container.slot.SlotFilterType;
 import com.raoulvdberge.refinedstorage.tile.externalstorage.TileExternalStorage;
 import net.minecraft.entity.player.EntityPlayer;
 import net.minecraft.inventory.Slot;
@@ -11,7 +11,7 @@ public class ContainerExternalStorage extends ContainerBase {
         super(tile, player);
 
         for (int i = 0; i < 9; ++i) {
-            addSlotToContainer(new SlotSpecimenType(tile, i, 8 + (18 * i), 20));
+            addSlotToContainer(new SlotFilterType(tile, i, 8 + (18 * i), 20));
         }
 
         addPlayerInventory(8, 141);
@@ -21,10 +21,10 @@ public class ContainerExternalStorage extends ContainerBase {
     public ItemStack transferStackInSlot(EntityPlayer player, int index) {
         Slot slot = getSlot(index);
 
-        if (slot != null && slot.getHasStack() && index >= 8) {
+        if (slot.getHasStack() && index >= 8) {
             return mergeItemStackToSpecimen(slot.getStack(), 0, 9);
         }
 
-        return null;
+        return ItemStack.EMPTY;
     }
 }

src/main/java/com/raoulvdberge/refinedstorage/container/ContainerFluidInterface.java

@@ -1,6 +1,6 @@
 package com.raoulvdberge.refinedstorage.container;
 
-import com.raoulvdberge.refinedstorage.container.slot.SlotSpecimenFluid;
+import com.raoulvdberge.refinedstorage.container.slot.SlotFilterFluid;
 import com.raoulvdberge.refinedstorage.tile.TileFluidInterface;
 import net.minecraft.entity.player.EntityPlayer;
 import net.minecraft.inventory.Slot;
@@ -16,30 +16,30 @@ public class ContainerFluidInterface extends ContainerBase {
         }
 
         addSlotToContainer(new SlotItemHandler(fluidInterface.getIn(), 0, 44, 32));
-        addSlotToContainer(new SlotSpecimenFluid(!fluidInterface.getWorld().isRemote, fluidInterface.getOut(), 0, 116, 32));
+        addSlotToContainer(new SlotFilterFluid(!fluidInterface.getWorld().isRemote, fluidInterface.getOut(), 0, 116, 32));
 
         addPlayerInventory(8, 122);
     }
 
     @Override
     public ItemStack transferStackInSlot(EntityPlayer player, int index) {
-        ItemStack stack = null;
+        ItemStack stack = ItemStack.EMPTY;
 
         Slot slot = getSlot(index);
 
-        if (slot != null && slot.getHasStack()) {
+        if (slot.getHasStack()) {
             stack = slot.getStack();
 
             if (index < 4 + 2) {
                 if (!mergeItemStack(stack, 4 + 2, inventorySlots.size(), false)) {
-                    return null;
+                    return ItemStack.EMPTY;
                 }
             } else if (!mergeItemStack(stack, 0, 4 + 1, false)) {
                 return mergeItemStackToSpecimen(stack, 5, 6);
             }
 
             if (stack.getCount() == 0) {
-                slot.putStack(null);
+                slot.putStack(ItemStack.EMPTY);
             } else {
                 slot.onSlotChanged();
             }

src/main/java/com/raoulvdberge/refinedstorage/container/ContainerFluidStorage.java

@@ -1,6 +1,6 @@
 package com.raoulvdberge.refinedstorage.container;
 
-import com.raoulvdberge.refinedstorage.container.slot.SlotSpecimenFluid;
+import com.raoulvdberge.refinedstorage.container.slot.SlotFilterFluid;
 import com.raoulvdberge.refinedstorage.tile.TileFluidStorage;
 import net.minecraft.entity.player.EntityPlayer;
 import net.minecraft.inventory.Slot;
@@ -11,7 +11,7 @@ public class ContainerFluidStorage extends ContainerBase {
         super(tile, player);
 
         for (int i = 0; i < 9; ++i) {
-            addSlotToContainer(new SlotSpecimenFluid(!tile.getWorld().isRemote, tile.getFilters(), i, 8 + (18 * i), 20));
+            addSlotToContainer(new SlotFilterFluid(!tile.getWorld().isRemote, tile.getFilters(), i, 8 + (18 * i), 20));
         }
 
         addPlayerInventory(8, 141);
@@ -21,10 +21,10 @@ public class ContainerFluidStorage extends ContainerBase {
     public ItemStack transferStackInSlot(EntityPlayer player, int index) {
         Slot slot = getSlot(index);
 
-        if (slot != null && slot.getHasStack() && index >= 8) {
+        if (slot.getHasStack() && index >= 8) {
             return mergeItemStackToSpecimen(slot.getStack(), 0, 9);
         }
 
-        return null;
+        return ItemStack.EMPTY;
     }
 }

src/main/java/com/raoulvdberge/refinedstorage/container/ContainerGrid.java

@@ -9,6 +9,7 @@ import com.raoulvdberge.refinedstorage.tile.grid.TileGrid;
 import com.raoulvdberge.refinedstorage.tile.grid.WirelessGrid;
 import net.minecraft.entity.player.EntityPlayer;
 import net.minecraft.entity.player.EntityPlayerMP;
+import net.minecraft.inventory.IContainerListener;
 import net.minecraft.inventory.Slot;
 import net.minecraft.item.ItemStack;
 import net.minecraftforge.items.SlotItemHandler;
@@ -47,7 +48,7 @@ public class ContainerGrid extends ContainerBase {
             int y = 96;
 
             for (int i = 0; i < 9; ++i) {
-                addSlotToContainer(new SlotSpecimenLegacy(((TileGrid) grid).getMatrix(), i, x, y));
+                addSlotToContainer(new SlotFilterLegacy(((TileGrid) grid).getMatrix(), i, x, y));
 
                 x += 18;
 
@@ -79,8 +80,8 @@ public class ContainerGrid extends ContainerBase {
             Slot slot = inventorySlots.get(i);
 
             if (slot instanceof SlotGridCrafting || slot == craftingResultSlot) {
-                for (int j = 0; j < listeners.size(); ++j) {
+                for (IContainerListener listener : listeners) {
-                    listeners.get(j).sendSlotContents(this, i, slot.getStack());
+                    listener.sendSlotContents(this, i, slot.getStack());
                 }
             }
         }
@@ -108,7 +109,7 @@ public class ContainerGrid extends ContainerBase {
             if (slot.getHasStack()) {
                 if (slot == craftingResultSlot) {
                     ((TileGrid) grid).onCraftedShift(this, player);
-                } else if (slot != patternResultSlot && !(slot instanceof SlotSpecimenLegacy)) {
+                } else if (slot != patternResultSlot && !(slot instanceof SlotFilterLegacy)) {
                     if (grid.getType() != EnumGridType.FLUID && grid.getItemHandler() != null) {
                         slot.putStack(RSUtils.getStack(grid.getItemHandler().onInsert((EntityPlayerMP) player, slot.getStack())));
                     } else if (grid.getType() == EnumGridType.FLUID && grid.getFluidHandler() != null) {

src/main/java/com/raoulvdberge/refinedstorage/container/ContainerGridFilter.java

@@ -1,6 +1,6 @@
 package com.raoulvdberge.refinedstorage.container;
 
-import com.raoulvdberge.refinedstorage.container.slot.SlotSpecimen;
+import com.raoulvdberge.refinedstorage.container.slot.SlotFilter;
 import com.raoulvdberge.refinedstorage.inventory.ItemHandlerGridFilter;
 import net.minecraft.entity.player.EntityPlayer;
 import net.minecraft.inventory.Slot;
@@ -17,7 +17,7 @@ public class ContainerGridFilter extends ContainerBase {
         this.filter = new ItemHandlerGridFilter(stack);
 
         for (int i = 0; i < 9; ++i) {
-            addSlotToContainer(new SlotSpecimen(filter, i, 8 + (i * 18), 20));
+            addSlotToContainer(new SlotFilter(filter, i, 8 + (i * 18), 20));
         }
 
         addPlayerInventory(8, 70);
@@ -29,18 +29,18 @@ public class ContainerGridFilter extends ContainerBase {
 
     @Override
     public ItemStack transferStackInSlot(EntityPlayer player, int index) {
-        ItemStack stack = null;
+        ItemStack stack = ItemStack.EMPTY;
 
         Slot slot = getSlot(index);
 
-        if (slot != null && slot.getHasStack()) {
+        if (slot.getHasStack()) {
             stack = slot.getStack();
 
             if (index > 9 - 1) {
                 return mergeItemStackToSpecimen(stack, 0, 9);
             }
 
-            return null;
+            return ItemStack.EMPTY;
         }
 
         return stack;

src/main/java/com/raoulvdberge/refinedstorage/container/ContainerImporter.java

@@ -1,6 +1,6 @@
 package com.raoulvdberge.refinedstorage.container;
 
-import com.raoulvdberge.refinedstorage.container.slot.SlotSpecimenType;
+import com.raoulvdberge.refinedstorage.container.slot.SlotFilterType;
 import com.raoulvdberge.refinedstorage.tile.TileImporter;
 import net.minecraft.entity.player.EntityPlayer;
 import net.minecraft.inventory.Slot;
@@ -16,7 +16,7 @@ public class ContainerImporter extends ContainerBase {
         }
 
         for (int i = 0; i < 9; ++i) {
-            addSlotToContainer(new SlotSpecimenType(importer, i, 8 + (18 * i), 20));
+            addSlotToContainer(new SlotFilterType(importer, i, 8 + (18 * i), 20));
         }
 
         addPlayerInventory(8, 55);
@@ -24,23 +24,23 @@ public class ContainerImporter extends ContainerBase {
 
     @Override
     public ItemStack transferStackInSlot(EntityPlayer player, int index) {
-        ItemStack stack = null;
+        ItemStack stack = ItemStack.EMPTY;
 
         Slot slot = getSlot(index);
 
-        if (slot != null && slot.getHasStack()) {
+        if (slot.getHasStack()) {
             stack = slot.getStack();
 
             if (index < 4) {
                 if (!mergeItemStack(stack, 4 + 9, inventorySlots.size(), false)) {
-                    return null;
+                    return ItemStack.EMPTY;
                 }
             } else if (!mergeItemStack(stack, 0, 4, false)) {
                 return mergeItemStackToSpecimen(stack, 4, 4 + 9);
             }
 
             if (stack.getCount() == 0) {
-                slot.putStack(null);
+                slot.putStack(ItemStack.EMPTY);
             } else {
                 slot.onSlotChanged();
             }

src/main/java/com/raoulvdberge/refinedstorage/container/ContainerInterface.java

@@ -1,7 +1,7 @@
 package com.raoulvdberge.refinedstorage.container;
 
+import com.raoulvdberge.refinedstorage.container.slot.SlotFilter;
 import com.raoulvdberge.refinedstorage.container.slot.SlotOutput;
-import com.raoulvdberge.refinedstorage.container.slot.SlotSpecimen;
 import com.raoulvdberge.refinedstorage.tile.TileInterface;
 import net.minecraft.entity.player.EntityPlayer;
 import net.minecraft.inventory.Slot;
@@ -17,7 +17,7 @@ public class ContainerInterface extends ContainerBase {
         }
 
         for (int i = 0; i < 9; ++i) {
-            addSlotToContainer(new SlotSpecimen(tile.getExportSpecimenItems(), i, 8 + (18 * i), 54, SlotSpecimen.SPECIMEN_SIZE));
+            addSlotToContainer(new SlotFilter(tile.getExportSpecimenItems(), i, 8 + (18 * i), 54, SlotFilter.SPECIMEN_SIZE));
         }
 
         for (int i = 0; i < 9; ++i) {
@@ -33,23 +33,23 @@ public class ContainerInterface extends ContainerBase {
 
     @Override
     public ItemStack transferStackInSlot(EntityPlayer player, int index) {
-        ItemStack stack = null;
+        ItemStack stack = ItemStack.EMPTY;
 
         Slot slot = getSlot(index);
 
-        if (slot != null && slot.getHasStack()) {
+        if (slot.getHasStack()) {
             stack = slot.getStack();
 
             if (index < 9) {
                 if (!mergeItemStack(stack, 9 + 9 + 9 + 4, inventorySlots.size(), false)) {
-                    return null;
+                    return ItemStack.EMPTY;
                 }
             } else if (!mergeItemStack(stack, 0, 9, false)) {
-                return null;
+                return ItemStack.EMPTY;
             }
 
             if (stack.getCount() == 0) {
-                slot.putStack(null);
+                slot.putStack(ItemStack.EMPTY);
             } else {
                 slot.onSlotChanged();
             }

src/main/java/com/raoulvdberge/refinedstorage/container/ContainerNetworkTransmitter.java

@@ -19,23 +19,23 @@ public class ContainerNetworkTransmitter extends ContainerBase {
 
     @Override
     public ItemStack transferStackInSlot(EntityPlayer player, int index) {
-        ItemStack stack = null;
+        ItemStack stack = ItemStack.EMPTY;
 
         Slot slot = getSlot(index);
 
-        if (slot != null && slot.getHasStack()) {
+        if (slot.getHasStack()) {
             stack = slot.getStack();
 
             if (index <= 1) {
                 if (!mergeItemStack(stack, 2, inventorySlots.size(), false)) {
-                    return null;
+                    return ItemStack.EMPTY;
                 }
             } else if (!mergeItemStack(stack, 0, 2, false)) {
-                return null;
+                return ItemStack.EMPTY;
             }
 
             if (stack.getCount() == 0) {
-                slot.putStack(null);
+                slot.putStack(ItemStack.EMPTY);
             } else {
                 slot.onSlotChanged();
             }

src/main/java/com/raoulvdberge/refinedstorage/container/ContainerProcessingPatternEncoder.java

@@ -1,7 +1,7 @@
 package com.raoulvdberge.refinedstorage.container;
 
+import com.raoulvdberge.refinedstorage.container.slot.SlotFilter;
 import com.raoulvdberge.refinedstorage.container.slot.SlotOutput;
-import com.raoulvdberge.refinedstorage.container.slot.SlotSpecimen;
 import com.raoulvdberge.refinedstorage.tile.TileProcessingPatternEncoder;
 import net.minecraft.entity.player.EntityPlayer;
 import net.minecraft.inventory.Slot;
@@ -22,7 +22,7 @@ public class ContainerProcessingPatternEncoder extends ContainerBase {
         int y = 20;
 
         for (int i = 0; i < 9 * 2; ++i) {
-            addSlotToContainer(new SlotSpecimen(encoder.getConfiguration(), i, x, y, SlotSpecimen.SPECIMEN_SIZE));
+            addSlotToContainer(new SlotFilter(encoder.getConfiguration(), i, x, y, SlotFilter.SPECIMEN_SIZE));
 
             x += 18;
 
@@ -43,23 +43,23 @@ public class ContainerProcessingPatternEncoder extends ContainerBase {
 
     @Override
     public ItemStack transferStackInSlot(EntityPlayer player, int index) {
-        ItemStack stack = null;
+        ItemStack stack = ItemStack.EMPTY;
 
         Slot slot = getSlot(index);
 
-        if (slot != null && !(slot instanceof SlotSpecimen) && slot.getHasStack()) {
+        if (!(slot instanceof SlotFilter) && slot.getHasStack()) {
             stack = slot.getStack();
 
             if (index < 2) {
                 if (!mergeItemStack(stack, 2 + 18, inventorySlots.size(), false)) {
-                    return null;
+                    return ItemStack.EMPTY;
                 }
             } else if (!mergeItemStack(stack, 0, 1, false)) {
-                return null;
+                return ItemStack.EMPTY;
             }
 
             if (stack.getCount() == 0) {
-                slot.putStack(null);
+                slot.putStack(ItemStack.EMPTY);
             } else {
                 slot.onSlotChanged();
             }
@@ -70,7 +70,7 @@ public class ContainerProcessingPatternEncoder extends ContainerBase {
 
     public void clearInputsAndOutputs() {
         for (int i = 2; i < 2 + (9 * 2); ++i) {
-            getSlot(i).putStack(null);
+            getSlot(i).putStack(ItemStack.EMPTY);
             getSlot(i).onSlotChanged();
         }
     }

src/main/java/com/raoulvdberge/refinedstorage/container/ContainerSolderer.java

@@ -32,31 +32,31 @@ public class ContainerSolderer extends ContainerBase {
 
     @Override
     public ItemStack transferStackInSlot(EntityPlayer player, int index) {
-        ItemStack stack = null;
+        ItemStack stack = ItemStack.EMPTY;
 
         Slot slot = getSlot(index);
 
-        if (slot != null && slot.getHasStack()) {
+        if (slot.getHasStack()) {
             stack = slot.getStack();
 
             if (index < 4) {
                 if (!mergeItemStack(stack, 4 + 4, inventorySlots.size(), false)) {
-                    return null;
+                    return ItemStack.EMPTY;
                 }
             } else if (index < 4 + 4) {
                 if (!mergeItemStack(stack, 4 + 4, inventorySlots.size(), false)) {
-                    return null;
+                    return ItemStack.EMPTY;
                 }
             } else {
                 if (stack.getItem() != RSItems.UPGRADE || !mergeItemStack(stack, 4, 4 + 4, false)) {
                     if (!mergeItemStack(stack, 0, 3, false)) { // 0 - 3 because we can't shift click to output slot
-                        return null;
+                        return ItemStack.EMPTY;
                     }
                 }
             }
 
             if (stack.getCount() == 0) {
-                slot.putStack(null);
+                slot.putStack(ItemStack.EMPTY);
             } else {
                 slot.onSlotChanged();
             }

src/main/java/com/raoulvdberge/refinedstorage/container/ContainerStorage.java

@@ -1,6 +1,6 @@
 package com.raoulvdberge.refinedstorage.container;
 
-import com.raoulvdberge.refinedstorage.container.slot.SlotSpecimen;
+import com.raoulvdberge.refinedstorage.container.slot.SlotFilter;
 import com.raoulvdberge.refinedstorage.tile.TileStorage;
 import net.minecraft.entity.player.EntityPlayer;
 import net.minecraft.inventory.Slot;
@@ -11,7 +11,7 @@ public class ContainerStorage extends ContainerBase {
         super(tile, player);
 
         for (int i = 0; i < 9; ++i) {
-            addSlotToContainer(new SlotSpecimen(tile.getFilters(), i, 8 + (18 * i), 20));
+            addSlotToContainer(new SlotFilter(tile.getFilters(), i, 8 + (18 * i), 20));
         }
 
         addPlayerInventory(8, 141);
@@ -21,10 +21,10 @@ public class ContainerStorage extends ContainerBase {
     public ItemStack transferStackInSlot(EntityPlayer player, int index) {
         Slot slot = getSlot(index);
 
-        if (slot != null && slot.getHasStack() && index >= 8) {
+        if (slot.getHasStack() && index >= 8) {
             return mergeItemStackToSpecimen(slot.getStack(), 0, 9);
         }
 
-        return null;
+        return ItemStack.EMPTY;
     }
 }

src/main/java/com/raoulvdberge/refinedstorage/container/ContainerWirelessTransmitter.java

@@ -19,7 +19,7 @@ public class ContainerWirelessTransmitter extends ContainerBase {
 
     @Override
     public ItemStack transferStackInSlot(EntityPlayer player, int index) {
-        ItemStack stack = null;
+        ItemStack stack = ItemStack.EMPTY;
 
         Slot slot = getSlot(index);
 
@@ -28,14 +28,14 @@ public class ContainerWirelessTransmitter extends ContainerBase {
 
             if (index < 4) {
                 if (!mergeItemStack(stack, 4, inventorySlots.size(), false)) {
-                    return null;
+                    return ItemStack.EMPTY;
                 }
             } else if (!mergeItemStack(stack, 0, 4, false)) {
-                return null;
+                return ItemStack.EMPTY;
             }
 
             if (stack.getCount() == 0) {
-                slot.putStack(null);
+                slot.putStack(ItemStack.EMPTY);
             } else {
                 slot.onSlotChanged();
             }

src/main/java/com/raoulvdberge/refinedstorage/container/slot/SlotDisabled.java

@@ -4,13 +4,15 @@ import net.minecraft.inventory.IInventory;
 import net.minecraft.inventory.Slot;
 import net.minecraft.item.ItemStack;
 
+import javax.annotation.Nonnull;
+
 public class SlotDisabled extends Slot {
     public SlotDisabled(IInventory inventory, int id, int x, int y) {
         super(inventory, id, x, y);
     }
 
     @Override
-    public boolean isItemValid(ItemStack stack) {
+    public boolean isItemValid(@Nonnull ItemStack stack) {
         return false;
     }
 }

src/main/java/com/raoulvdberge/refinedstorage/container/slot/SlotFilter.java

@@ -11,21 +11,22 @@ import net.minecraftforge.common.IPlantable;
 import net.minecraftforge.items.IItemHandler;
 import net.minecraftforge.items.SlotItemHandler;
 
+import javax.annotation.Nonnull;
 import java.lang.reflect.Field;
 
-public class SlotSpecimen extends SlotItemHandler {
+public class SlotFilter extends SlotItemHandler {
     public static final int SPECIMEN_SIZE = 1;
     public static final int SPECIMEN_BLOCK = 2;
 
     private int flags = 0;
 
-    public SlotSpecimen(IItemHandler handler, int id, int x, int y, int flags) {
+    public SlotFilter(IItemHandler handler, int id, int x, int y, int flags) {
         super(handler, id, x, y);
 
         this.flags = flags;
     }
 
-    public SlotSpecimen(IItemHandler handler, int id, int x, int y) {
+    public SlotFilter(IItemHandler handler, int id, int x, int y) {
         this(handler, id, x, y, 0);
     }
 
@@ -35,7 +36,7 @@ public class SlotSpecimen extends SlotItemHandler {
     }
 
     @Override
-    public boolean isItemValid(ItemStack stack) {
+    public boolean isItemValid(@Nonnull ItemStack stack) {
         if (super.isItemValid(stack)) {
             if (isBlockOnly()) {
                 return stack.getItem() instanceof ItemBlock || stack.getItem() instanceof ItemBlockSpecial || stack.getItem() instanceof IPlantable || stack.getItem() instanceof ItemSkull;
@@ -48,8 +49,8 @@ public class SlotSpecimen extends SlotItemHandler {
     }
 
     @Override
-    public void putStack(ItemStack stack) {
+    public void putStack(@Nonnull ItemStack stack) {
-        if (stack != null && !isWithSize()) {
+        if (!stack.isEmpty() && !isWithSize()) {
             stack.setCount(1);
         }
 

src/main/java/com/raoulvdberge/refinedstorage/container/slot/SlotFilterFluid.java

@@ -3,18 +3,21 @@ package com.raoulvdberge.refinedstorage.container.slot;
 import net.minecraft.item.ItemStack;
 import net.minecraftforge.items.IItemHandler;
 
-public class SlotSpecimenFluid extends SlotSpecimen {
+import javax.annotation.Nonnull;
+
+public class SlotFilterFluid extends SlotFilter {
     private boolean server;
 
-    public SlotSpecimenFluid(boolean server, IItemHandler handler, int id, int x, int y) {
+    public SlotFilterFluid(boolean server, IItemHandler handler, int id, int x, int y) {
         super(handler, id, x, y);
 
         this.server = server;
     }
 
     @Override
+    @Nonnull
     public ItemStack getStack() {
-        return server ? super.getStack() : null;
+        return server ? super.getStack() : ItemStack.EMPTY;
     }
 
     public ItemStack getRealStack() {

src/main/java/com/raoulvdberge/refinedstorage/container/slot/SlotFilterLegacy.java

@@ -6,8 +6,10 @@ import net.minecraft.inventory.IInventory;
 import net.minecraft.inventory.Slot;
 import net.minecraft.item.ItemStack;
 
-public class SlotSpecimenLegacy extends Slot {
+import javax.annotation.Nonnull;
-    public SlotSpecimenLegacy(IInventory inventory, int id, int x, int y) {
+
+public class SlotFilterLegacy extends Slot {
+    public SlotFilterLegacy(IInventory inventory, int id, int x, int y) {
         super(inventory, id, x, y);
     }
 
@@ -22,8 +24,8 @@ public class SlotSpecimenLegacy extends Slot {
     }
 
     @Override
-    public void putStack(ItemStack stack) {
+    public void putStack(@Nonnull ItemStack stack) {
-        if (stack != null) {
+        if (!stack.isEmpty()) {
             stack.setCount(1);
         }
 

src/main/java/com/raoulvdberge/refinedstorage/container/slot/SlotFilterType.java

@@ -5,16 +5,18 @@ import net.minecraft.item.ItemStack;
 import net.minecraft.tileentity.TileEntity;
 import net.minecraftforge.items.IItemHandler;
 
-public class SlotSpecimenType extends SlotSpecimen {
+import javax.annotation.Nonnull;
+
+public class SlotFilterType extends SlotFilter {
     private IType type;
 
-    public SlotSpecimenType(IType type, int id, int x, int y, int flags) {
+    public SlotFilterType(IType type, int id, int x, int y, int flags) {
         super(null, id, x, y, flags);
 
         this.type = type;
     }
 
-    public SlotSpecimenType(IType type, int id, int x, int y) {
+    public SlotFilterType(IType type, int id, int x, int y) {
         this(type, id, x, y, 0);
     }
 
@@ -34,8 +36,9 @@ public class SlotSpecimenType extends SlotSpecimen {
     }
 
     @Override
+    @Nonnull
     public ItemStack getStack() {
-        return (type.getType() == IType.ITEMS || !((TileEntity) type).getWorld().isRemote) ? super.getStack() : null;
+        return (type.getType() == IType.ITEMS || !((TileEntity) type).getWorld().isRemote) ? super.getStack() : ItemStack.EMPTY;
     }
 
     public ItemStack getRealStack() {

src/main/java/com/raoulvdberge/refinedstorage/container/slot/SlotGridCraftingResult.java

@@ -7,6 +7,8 @@ import net.minecraft.inventory.SlotCrafting;
 import net.minecraft.item.ItemStack;
 import net.minecraftforge.fml.common.FMLCommonHandler;
 
+import javax.annotation.Nonnull;
+
 public class SlotGridCraftingResult extends SlotCrafting {
     private ContainerGrid container;
     private TileGrid grid;
@@ -19,7 +21,8 @@ public class SlotGridCraftingResult extends SlotCrafting {
     }
 
     @Override
-    public ItemStack onTake(EntityPlayer player, ItemStack stack) {
+    @Nonnull
+    public ItemStack onTake(EntityPlayer player, @Nonnull ItemStack stack) {
         FMLCommonHandler.instance().firePlayerCraftingEvent(player, stack, grid.getMatrix());
 
         onCrafting(stack);
@@ -30,6 +33,6 @@ public class SlotGridCraftingResult extends SlotCrafting {
             container.sendCraftingSlots();
         }
 
-        return null;
+        return ItemStack.EMPTY;
     }
 }

src/main/java/com/raoulvdberge/refinedstorage/container/slot/SlotOutput.java

@@ -4,13 +4,15 @@ import net.minecraft.item.ItemStack;
 import net.minecraftforge.items.IItemHandler;
 import net.minecraftforge.items.SlotItemHandler;
 
+import javax.annotation.Nonnull;
+
 public class SlotOutput extends SlotItemHandler {
     public SlotOutput(IItemHandler inventory, int id, int x, int y) {
         super(inventory, id, x, y);
     }
 
     @Override
-    public boolean isItemValid(ItemStack stack) {
+    public boolean isItemValid(@Nonnull ItemStack stack) {
         return false;
     }
 }

src/main/java/com/raoulvdberge/refinedstorage/gui/GuiNetworkTransmitter.java

@@ -35,7 +35,7 @@ public class GuiNetworkTransmitter extends GuiBase {
 
         String distance;
 
-        if (networkTransmitter.getNetworkCard().getStackInSlot(0) == null) {
+        if (networkTransmitter.getNetworkCard().getStackInSlot(0).isEmpty()) {
             distance = t("gui.refinedstorage:network_transmitter.missing_card");
         } else if (!TileNetworkTransmitter.RECEIVER_DIMENSION_SUPPORTED.getValue()) {
             distance = t("gui.refinedstorage:network_transmitter.missing_upgrade");

src/main/java/com/raoulvdberge/refinedstorage/gui/GuiPriority.java

@@ -14,7 +14,7 @@ public class GuiPriority extends GuiCraftingStart {
     public GuiPriority(GuiBase parent, TileDataParameter<Integer> priority) {
         super(parent, null, new Container() {
             @Override
-            public boolean canInteractWith(EntityPlayer playerIn) {
+            public boolean canInteractWith(EntityPlayer player) {
                 return false;
             }
         }, 164, 92);

src/main/java/com/raoulvdberge/refinedstorage/inventory/ItemHandlerGridFilterInGrid.java

@@ -28,13 +28,13 @@ public class ItemHandlerGridFilterInGrid extends ItemHandlerBasic {
         for (int i = 0; i < getSlots(); ++i) {
             ItemStack filter = getStackInSlot(i);
 
-            if (filter != null) {
+            if (!filter.isEmpty()) {
                 int compare = ItemGridFilter.getCompare(filter);
 
                 ItemHandlerGridFilter items = new ItemHandlerGridFilter(filter);
 
                 for (ItemStack item : items.getFilteredItems()) {
-                    if (item != null) {
+                    if (!item.isEmpty()) {
                         filteredItems.add(new GridFilteredItem(item, compare));
                     }
                 }

src/main/java/com/raoulvdberge/refinedstorage/inventory/ItemHandlerUpgrade.java

@@ -19,7 +19,7 @@ public class ItemHandlerUpgrade extends ItemHandlerBasic {
 
     public int getSpeed(int speed, int speedIncrease) {
         for (int i = 0; i < getSlots(); ++i) {
-            if (getStackInSlot(i) != null && getStackInSlot(i).getItemDamage() == ItemUpgrade.TYPE_SPEED) {
+            if (!getStackInSlot(i).isEmpty() && getStackInSlot(i).getItemDamage() == ItemUpgrade.TYPE_SPEED) {
                 speed -= speedIncrease;
             }
         }
@@ -35,7 +35,7 @@ public class ItemHandlerUpgrade extends ItemHandlerBasic {
         int upgrades = 0;
 
         for (int i = 0; i < getSlots(); ++i) {
-            if (getStackInSlot(i) != null && getStackInSlot(i).getItemDamage() == type) {
+            if (!getStackInSlot(i).isEmpty() && getStackInSlot(i).getItemDamage() == type) {
                 upgrades++;
             }
         }
@@ -47,7 +47,7 @@ public class ItemHandlerUpgrade extends ItemHandlerBasic {
         int usage = 0;
 
         for (int i = 0; i < getSlots(); ++i) {
-            if (getStackInSlot(i) != null) {
+            if (!getStackInSlot(i).isEmpty()) {
                 usage += ItemUpgrade.getEnergyUsage(getStackInSlot(i));
             }
         }
@@ -57,7 +57,7 @@ public class ItemHandlerUpgrade extends ItemHandlerBasic {
 
     public int getFortuneLevel() {
         for (int i = 0; i < getSlots(); ++i) {
-            if (getStackInSlot(i) != null && getStackInSlot(i).getItemDamage() == ItemUpgrade.TYPE_FORTUNE) {
+            if (!getStackInSlot(i).isEmpty() && getStackInSlot(i).getItemDamage() == ItemUpgrade.TYPE_FORTUNE) {
                 return ItemUpgrade.getFortuneLevel(getStackInSlot(i));
             }
         }

src/main/java/com/raoulvdberge/refinedstorage/tile/TileConstructor.java

@@ -4,7 +4,7 @@ import com.mojang.authlib.GameProfile;
 import com.raoulvdberge.refinedstorage.RS;
 import com.raoulvdberge.refinedstorage.RSUtils;
 import com.raoulvdberge.refinedstorage.api.util.IComparer;
-import com.raoulvdberge.refinedstorage.container.slot.SlotSpecimen;
+import com.raoulvdberge.refinedstorage.container.slot.SlotFilter;
 import com.raoulvdberge.refinedstorage.inventory.ItemHandlerBasic;
 import com.raoulvdberge.refinedstorage.inventory.ItemHandlerFluid;
 import com.raoulvdberge.refinedstorage.inventory.ItemHandlerUpgrade;
@@ -72,7 +72,7 @@ public class TileConstructor extends TileNode implements IComparable, IType {
             super.onContentsChanged(slot);
 
             item = getStackInSlot(slot) == null ? null : getStackInSlot(slot).copy();
-            block = SlotSpecimen.getBlockState(getWorld(), pos.offset(getDirection()), getStackInSlot(slot));
+            block = SlotFilter.getBlockState(getWorld(), pos.offset(getDirection()), getStackInSlot(slot));
         }
     };