A wee bit of a cleanup of the API

- Move some method over to defaulted methods
 - Use Objects rather than Preconditions

src/main/java/dan200/computercraft/shared/turtle/upgrades/TurtleCraftingTable.java

@@ -7,14 +7,16 @@
 package dan200.computercraft.shared.turtle.upgrades;
 
 import dan200.computercraft.api.peripheral.IPeripheral;
-import dan200.computercraft.api.turtle.*;
+import dan200.computercraft.api.turtle.ITurtleAccess;
+import dan200.computercraft.api.turtle.ITurtleUpgrade;
+import dan200.computercraft.api.turtle.TurtleSide;
+import dan200.computercraft.api.turtle.TurtleUpgradeType;
 import net.minecraft.client.Minecraft;
 import net.minecraft.client.renderer.block.model.IBakedModel;
 import net.minecraft.client.renderer.block.model.ModelManager;
 import net.minecraft.client.renderer.block.model.ModelResourceLocation;
 import net.minecraft.init.Blocks;
 import net.minecraft.item.ItemStack;
-import net.minecraft.util.EnumFacing;
 import net.minecraft.util.ResourceLocation;
 import net.minecraftforge.fml.relauncher.Side;
 import net.minecraftforge.fml.relauncher.SideOnly;
@@ -61,14 +63,14 @@ public class TurtleCraftingTable implements ITurtleUpgrade
     {
         return "upgrade.minecraft:crafting_table.adjective";
     }
-    
+
     @Nonnull
     @Override
     public TurtleUpgradeType getType()
     {
         return TurtleUpgradeType.Peripheral;
     }
-    
+
     @Nonnull
     @Override
     public ItemStack getCraftingItem()
@@ -82,13 +84,6 @@ public class TurtleCraftingTable implements ITurtleUpgrade
         return new CraftingTablePeripheral( turtle );
     }
 
-    @Nonnull
-    @Override
-    public TurtleCommandResult useTool( @Nonnull ITurtleAccess turtle, @Nonnull TurtleSide side, @Nonnull TurtleVerb verb, @Nonnull EnumFacing dir )
-    {
-        return TurtleCommandResult.failure();
-    }
-
     @SideOnly( Side.CLIENT )
     private void loadModelLocations()
     {

src/main/java/dan200/computercraft/shared/turtle/upgrades/TurtleSpeaker.java

@@ -8,7 +8,10 @@
 package dan200.computercraft.shared.turtle.upgrades;
 
 import dan200.computercraft.api.peripheral.IPeripheral;
-import dan200.computercraft.api.turtle.*;
+import dan200.computercraft.api.turtle.ITurtleAccess;
+import dan200.computercraft.api.turtle.ITurtleUpgrade;
+import dan200.computercraft.api.turtle.TurtleSide;
+import dan200.computercraft.api.turtle.TurtleUpgradeType;
 import dan200.computercraft.shared.peripheral.PeripheralType;
 import dan200.computercraft.shared.peripheral.common.PeripheralItemFactory;
 import dan200.computercraft.shared.peripheral.speaker.SpeakerPeripheral;
@@ -17,13 +20,13 @@ import net.minecraft.client.renderer.block.model.IBakedModel;
 import net.minecraft.client.renderer.block.model.ModelManager;
 import net.minecraft.client.renderer.block.model.ModelResourceLocation;
 import net.minecraft.item.ItemStack;
-import net.minecraft.util.EnumFacing;
 import net.minecraft.util.ResourceLocation;
 import net.minecraft.util.math.BlockPos;
 import net.minecraft.world.World;
 import net.minecraftforge.fml.relauncher.Side;
 import net.minecraftforge.fml.relauncher.SideOnly;
 import org.apache.commons.lang3.tuple.Pair;
+
 import javax.annotation.Nonnull;
 import javax.vecmath.Matrix4f;
 
@@ -34,7 +37,7 @@ public class TurtleSpeaker implements ITurtleUpgrade
         // Members
         ITurtleAccess m_turtle;
 
-        public Peripheral(ITurtleAccess turtle)
+        public Peripheral( ITurtleAccess turtle )
         {
             super();
             m_turtle = turtle;
@@ -59,9 +62,9 @@ public class TurtleSpeaker implements ITurtleUpgrade
         }
 
         @Override
-        public boolean equals(IPeripheral other)
+        public boolean equals( IPeripheral other )
         {
-            if (other instanceof Peripheral)
+            if( other instanceof Peripheral )
             {
                 Peripheral otherPeripheral = (Peripheral) other;
                 return otherPeripheral.m_turtle == m_turtle;
@@ -124,14 +127,7 @@ public class TurtleSpeaker implements ITurtleUpgrade
     @Override
     public IPeripheral createPeripheral( @Nonnull ITurtleAccess turtle, @Nonnull TurtleSide side )
     {
-        return new TurtleSpeaker.Peripheral(turtle);
-    }
-
-    @Nonnull
-    @Override
-    public TurtleCommandResult useTool( @Nonnull ITurtleAccess turtleAccess, @Nonnull TurtleSide turtleSide, @Nonnull TurtleVerb verb, @Nonnull EnumFacing direction )
-    {
-        return TurtleCommandResult.failure();
+        return new TurtleSpeaker.Peripheral( turtle );
     }
 
     @SideOnly( Side.CLIENT )
@@ -166,7 +162,7 @@ public class TurtleSpeaker implements ITurtleUpgrade
     public void update( @Nonnull ITurtleAccess turtle, @Nonnull TurtleSide turtleSide )
     {
         IPeripheral turtlePeripheral = turtle.getPeripheral( turtleSide );
-        if ( turtlePeripheral instanceof Peripheral )
+        if( turtlePeripheral instanceof Peripheral )
         {
             Peripheral peripheral = (Peripheral) turtlePeripheral;
             peripheral.update();

src/main/java/dan200/computercraft/shared/turtle/upgrades/TurtleTool.java

@@ -7,7 +7,6 @@
 package dan200.computercraft.shared.turtle.upgrades;
 
 import dan200.computercraft.ComputerCraft;
-import dan200.computercraft.api.peripheral.IPeripheral;
 import dan200.computercraft.api.turtle.*;
 import dan200.computercraft.api.turtle.event.TurtleAttackEvent;
 import dan200.computercraft.api.turtle.event.TurtleBlockEvent;
@@ -94,12 +93,6 @@ public class TurtleTool implements ITurtleUpgrade
         return m_item.copy();
     }
 
-    @Override
-    public IPeripheral createPeripheral( @Nonnull ITurtleAccess turtle, @Nonnull TurtleSide side )
-    {
-        return null;
-    }
-
     @Nonnull
     @Override
     @SideOnly( Side.CLIENT )