Better version control

HolographicDisplays/Plugin/com/gmail/filoghost/holographicdisplays/HolographicDisplays.java

@@ -28,6 +28,7 @@ import com.gmail.filoghost.holographicdisplays.placeholder.PlaceholdersManager;
 import com.gmail.filoghost.holographicdisplays.task.BungeeCleanupTask;
 import com.gmail.filoghost.holographicdisplays.task.StartupLoadHologramsTask;
 import com.gmail.filoghost.holographicdisplays.task.WorldPlayerCounterTask;
+import com.gmail.filoghost.holographicdisplays.util.MinecraftVersion;
 import com.gmail.filoghost.holographicdisplays.util.VersionUtils;
 
 public class HolographicDisplays extends JavaPlugin {
@@ -41,15 +42,6 @@ public class HolographicDisplays extends JavaPlugin {
 	// The command handler, just in case a plugin wants to register more commands.
 	private HologramsCommandHandler commandHandler;
 	
-	// Since 1.8 we use armor stands instead of wither skulls.
-	private static boolean is18orGreater;
-	
-	// Since 1.9 there is a different offset for the nametag.
-	private static boolean is19orGreater;
-	
-	// Since 1.10 there is a difference in the entity metadata packet index for items.
-	private static boolean is110orGreater;
-	
 	// The new version found by the updater, null if there is no new version.
 	private static String newVersion;
 	
@@ -114,34 +106,44 @@ public class HolographicDisplays extends JavaPlugin {
 		// It's simple, we don't need reflection.
 		if ("v1_7_R1".equals(version)) {
 			nmsManager = new com.gmail.filoghost.holographicdisplays.nms.v1_7_R1.NmsManagerImpl();
+			MinecraftVersion.set(MinecraftVersion.v1_7);
+			
 		} else if ("v1_7_R2".equals(version)) {
 			nmsManager = new com.gmail.filoghost.holographicdisplays.nms.v1_7_R2.NmsManagerImpl();
+			MinecraftVersion.set(MinecraftVersion.v1_7);
+			
 		} else if ("v1_7_R3".equals(version)) {
 			nmsManager = new com.gmail.filoghost.holographicdisplays.nms.v1_7_R3.NmsManagerImpl();
+			MinecraftVersion.set(MinecraftVersion.v1_7);
+			
 		} else if ("v1_7_R4".equals(version)) {
 			nmsManager = new com.gmail.filoghost.holographicdisplays.nms.v1_7_R4.NmsManagerImpl();
+			MinecraftVersion.set(MinecraftVersion.v1_7);
+			
 		} else if ("v1_8_R1".equals(version)) {
-			is18orGreater = true;
 			nmsManager = new com.gmail.filoghost.holographicdisplays.nms.v1_8_R1.NmsManagerImpl();
+			MinecraftVersion.set(MinecraftVersion.v1_8);
+			
 		} else if ("v1_8_R2".equals(version)) {
-			is18orGreater = true;
 			nmsManager = new com.gmail.filoghost.holographicdisplays.nms.v1_8_R2.NmsManagerImpl();
+			MinecraftVersion.set(MinecraftVersion.v1_8);
+			
 		} else if ("v1_8_R3".equals(version)) {
-			is18orGreater = true;
 			nmsManager = new com.gmail.filoghost.holographicdisplays.nms.v1_8_R3.NmsManagerImpl();
+			MinecraftVersion.set(MinecraftVersion.v1_8);
+			
 		} else if ("v1_9_R1".equals(version)) {
-			is18orGreater = true;
-			is19orGreater = true;
 			nmsManager = new com.gmail.filoghost.holographicdisplays.nms.v1_9_R1.NmsManagerImpl();
+			MinecraftVersion.set(MinecraftVersion.v1_9);
+			
 		} else if ("v1_9_R2".equals(version)) {
-			is18orGreater = true;
-			is19orGreater = true;
 			nmsManager = new com.gmail.filoghost.holographicdisplays.nms.v1_9_R2.NmsManagerImpl();
+			MinecraftVersion.set(MinecraftVersion.v1_9);
+			
 		} else if ("v1_10_R1".equals(version)) {
-			is18orGreater = true;
-			is19orGreater = true;
-			is110orGreater = true;
 			nmsManager = new com.gmail.filoghost.holographicdisplays.nms.v1_10_R1.NmsManagerImpl();
+			MinecraftVersion.set(MinecraftVersion.v1_10);
+			
 		} else {
 			printWarnAndDisable(
 				"******************************************************",
@@ -184,10 +186,10 @@ public class HolographicDisplays extends JavaPlugin {
 				if (VersionUtils.classExists("com.comphenix.protocol.wrappers.WrappedDataWatcher$WrappedDataWatcherObject")) {
 					// Only the new version contains this class
 					getLogger().info("Found ProtocolLib, using new version.");
-					protocolLibHook = new com.gmail.filoghost.holographicdisplays.bridge.protocollib.current.ProtocolLibHookImpl(is19orGreater, is110orGreater);
+					protocolLibHook = new com.gmail.filoghost.holographicdisplays.bridge.protocollib.current.ProtocolLibHookImpl();
 				} else {
 					getLogger().info("Found ProtocolLib, using old version.");
-					protocolLibHook = new com.gmail.filoghost.holographicdisplays.bridge.protocollib.old.ProtocolLibHookImpl(is18orGreater);
+					protocolLibHook = new com.gmail.filoghost.holographicdisplays.bridge.protocollib.old.ProtocolLibHookImpl();
 				}
 				
 				if (protocolLibHook.hook(this, nmsManager)) {
@@ -278,18 +280,6 @@ public class HolographicDisplays extends JavaPlugin {
 	public HologramsCommandHandler getCommandHandler() {
 		return commandHandler;
 	}
-
-	public static boolean is18orGreater() {
-		return is18orGreater;
-	}
-	
-	public static boolean is19orGreater() {
-		return is19orGreater;
-	}
-	
-	public static boolean is110orGreater() {
-		return is19orGreater;
-	}
 	
 	private static void printWarnAndDisable(String... messages) {
 		StringBuffer buffer = new StringBuffer("\n ");

HolographicDisplays/Plugin/com/gmail/filoghost/holographicdisplays/bridge/protocollib/current/ProtocolLibHookImpl.java

@@ -32,6 +32,7 @@ import com.gmail.filoghost.holographicdisplays.object.line.CraftItemLine;
 import com.gmail.filoghost.holographicdisplays.object.line.CraftTextLine;
 import com.gmail.filoghost.holographicdisplays.object.line.CraftTouchSlimeLine;
 import com.gmail.filoghost.holographicdisplays.object.line.CraftTouchableLine;
+import com.gmail.filoghost.holographicdisplays.util.MinecraftVersion;
 import com.gmail.filoghost.holographicdisplays.util.Utils;
 import com.google.common.base.Optional;
 
@@ -42,26 +43,15 @@ import com.google.common.base.Optional;
  */
 public class ProtocolLibHookImpl implements ProtocolLibHook {
 	
-	private boolean is1_9orGreater;
-	private boolean is110orGreater;
-	
 	private NMSManager nmsManager;
 	
-	private boolean initSerializers;
+	private Serializer itemSerializer, intSerializer, byteSerializer;
-	private Serializer
-		itemSerializer,
-		intSerializer,
-		byteSerializer;
 	
-	public ProtocolLibHookImpl(boolean is19orGreater, boolean is110orGreater) {
+	private int itemstackMetadataWatcherIndex;
-		this.is1_9orGreater = is19orGreater;
-		this.is110orGreater = is110orGreater;
-	}
 	
 	@Override
 	public boolean hook(Plugin plugin, NMSManager nmsManager) {
-		this.nmsManager = nmsManager;
+		
-			
 		String version = Bukkit.getPluginManager().getPlugin("ProtocolLib").getDescription().getVersion();
 		if (version.matches(Pattern.quote("3.7-SNAPSHOT") + ".+")) {
 			Bukkit.getConsoleSender().sendMessage(
@@ -71,6 +61,24 @@ public class ProtocolLibHookImpl implements ProtocolLibHook {
 					"Please update ProtocolLib.");
 			return false;
 		}
+		
+		this.nmsManager = nmsManager;
+		
+		if (MinecraftVersion.isGreaterEqualThan(MinecraftVersion.v1_9)) {
+			if (MinecraftVersion.isGreaterEqualThan(MinecraftVersion.v1_10)) {
+				itemstackMetadataWatcherIndex = 6;
+			} else {
+				itemstackMetadataWatcherIndex = 5;
+			}
+		} else {
+			itemstackMetadataWatcherIndex = 10;
+		}
+		
+		if (MinecraftVersion.isGreaterEqualThan(MinecraftVersion.v1_9)) {
+			itemSerializer = Registry.get(MinecraftReflection.getItemStackClass());
+			intSerializer = Registry.get(Integer.class);
+			byteSerializer = Registry.get(Byte.class);
+		}
 
 		AdapterParameteters params = PacketAdapter
 				.params()
@@ -183,7 +191,7 @@ public class ProtocolLibHookImpl implements ProtocolLibHook {
 									String replacement = customName.replace("{player}", player.getName()).replace("{displayname}", player.getDisplayName());
 
 									WrappedWatchableObject newWatchableObject;
-									if (is1_9orGreater) {
+									if (MinecraftVersion.isGreaterEqualThan(MinecraftVersion.v1_9)) {
 										// The other constructor does not work in 1.9+.
 										newWatchableObject = new WrappedWatchableObject(watchableObject.getWatcherObject(), replacement);
 									} else {
@@ -255,19 +263,12 @@ public class ProtocolLibHookImpl implements ProtocolLibHook {
 						WrapperPlayServerEntityMetadata itemDataPacket = new WrapperPlayServerEntityMetadata();
 						WrappedDataWatcher dataWatcher = new WrappedDataWatcher();
 						
-						if (is1_9orGreater) {
+						if (MinecraftVersion.isGreaterEqualThan(MinecraftVersion.v1_9)) {
-							if (!initSerializers) {
+							dataWatcher.setObject(new WrappedDataWatcherObject(itemstackMetadataWatcherIndex, itemSerializer), Optional.of(itemLine.getNmsItem().getRawItemStack()));
-								itemSerializer = Registry.get(MinecraftReflection.getItemStackClass());
-								intSerializer = Registry.get(Integer.class);
-								byteSerializer = Registry.get(Byte.class);
-								initSerializers = true;
-							}
-	
-							dataWatcher.setObject(new WrappedDataWatcherObject(is110orGreater ? 6 : 5, itemSerializer), Optional.of(itemLine.getNmsItem().getRawItemStack()));
 							dataWatcher.setObject(new WrappedDataWatcherObject(1, intSerializer), 300);
 							dataWatcher.setObject(new WrappedDataWatcherObject(0, byteSerializer), (byte) 0);
 						} else {
-							dataWatcher.setObject(10, itemLine.getNmsItem().getRawItemStack());
+							dataWatcher.setObject(itemstackMetadataWatcherIndex, itemLine.getNmsItem().getRawItemStack());
 							dataWatcher.setObject(1, 300);
 							dataWatcher.setObject(0, (byte) 0);
 						}
@@ -302,7 +303,7 @@ public class ProtocolLibHookImpl implements ProtocolLibHook {
 	
 	
 	private AbstractPacket getAttachPacket(int vehicleId, int passengerId) {
-		if (is1_9orGreater) {
+		if (MinecraftVersion.isGreaterEqualThan(MinecraftVersion.v1_9)) {
 			WrapperPlayServerMount attachPacket = new WrapperPlayServerMount();
 			attachPacket.setVehicleId(vehicleId);
 			attachPacket.setPassengers(new int[] {passengerId});

HolographicDisplays/Plugin/com/gmail/filoghost/holographicdisplays/bridge/protocollib/old/ProtocolLibHookImpl.java

@@ -16,7 +16,6 @@ import com.comphenix.protocol.events.PacketContainer;
 import com.comphenix.protocol.events.PacketEvent;
 import com.comphenix.protocol.wrappers.WrappedDataWatcher;
 import com.comphenix.protocol.wrappers.WrappedWatchableObject;
-import com.gmail.filoghost.holographicdisplays.HolographicDisplays;
 import com.gmail.filoghost.holographicdisplays.bridge.protocollib.ProtocolLibHook;
 import com.gmail.filoghost.holographicdisplays.bridge.protocollib.old.WrapperPlayServerSpawnEntity.ObjectTypes;
 import com.gmail.filoghost.holographicdisplays.nms.interfaces.NMSManager;
@@ -27,6 +26,7 @@ import com.gmail.filoghost.holographicdisplays.object.line.CraftItemLine;
 import com.gmail.filoghost.holographicdisplays.object.line.CraftTextLine;
 import com.gmail.filoghost.holographicdisplays.object.line.CraftTouchSlimeLine;
 import com.gmail.filoghost.holographicdisplays.object.line.CraftTouchableLine;
+import com.gmail.filoghost.holographicdisplays.util.MinecraftVersion;
 import com.gmail.filoghost.holographicdisplays.util.Utils;
 import com.gmail.filoghost.holographicdisplays.util.VersionUtils;
 
@@ -37,21 +37,15 @@ import com.gmail.filoghost.holographicdisplays.util.VersionUtils;
  */
 public class ProtocolLibHookImpl implements ProtocolLibHook {
 
-	private boolean is18orGreater;
-
 	private NMSManager nmsManager;
 
 	private int customNameWatcherIndex;
-	
-	public ProtocolLibHookImpl(boolean is18orGreater) {
-		this.is18orGreater = is18orGreater;
-	}
 
 	@Override
 	public boolean hook(Plugin plugin, NMSManager nmsManager) {
 		this.nmsManager = nmsManager;
 
-		if (is18orGreater) {
+		if (MinecraftVersion.isGreaterEqualThan(MinecraftVersion.v1_8)) {
 			customNameWatcherIndex = 2;
 		} else {
 			customNameWatcherIndex = 10;
@@ -232,7 +226,7 @@ public class ProtocolLibHookImpl implements ProtocolLibHook {
 						itemPacket.sendPacket(player);
 
 						AbstractPacket vehiclePacket;
-						if (HolographicDisplays.is18orGreater()) {
+						if (MinecraftVersion.isGreaterEqualThan(MinecraftVersion.v1_8)) {
 							// In 1.8 we have armor stands, that are living entities.
 							vehiclePacket = new WrapperPlayServerSpawnEntityLiving(itemLine.getNmsVehicle().getBukkitEntityNMS());
 						} else {
@@ -268,7 +262,7 @@ public class ProtocolLibHookImpl implements ProtocolLibHook {
 					if (touchSlime.isSpawned()) {
 						AbstractPacket vehiclePacket;
 
-						if (HolographicDisplays.is18orGreater()) {
+						if (MinecraftVersion.isGreaterEqualThan(MinecraftVersion.v1_8)) {
 							// Armor stand vehicle
 							vehiclePacket = new WrapperPlayServerSpawnEntityLiving(touchSlime.getNmsVehicle().getBukkitEntityNMS());
 						} else {

HolographicDisplays/Plugin/com/gmail/filoghost/holographicdisplays/commands/main/subs/FixCommand.java

@@ -7,7 +7,6 @@ import org.bukkit.Material;
 import org.bukkit.block.Block;
 import org.bukkit.command.CommandSender;
 
-import com.gmail.filoghost.holographicdisplays.HolographicDisplays;
 import com.gmail.filoghost.holographicdisplays.commands.Colors;
 import com.gmail.filoghost.holographicdisplays.commands.CommandValidator;
 import com.gmail.filoghost.holographicdisplays.commands.Strings;
@@ -15,6 +14,7 @@ import com.gmail.filoghost.holographicdisplays.commands.main.HologramSubCommand;
 import com.gmail.filoghost.holographicdisplays.exception.CommandException;
 import com.gmail.filoghost.holographicdisplays.object.NamedHologram;
 import com.gmail.filoghost.holographicdisplays.object.NamedHologramManager;
+import com.gmail.filoghost.holographicdisplays.util.MinecraftVersion;
 
 public class FixCommand extends HologramSubCommand {
 
@@ -37,7 +37,7 @@ public class FixCommand extends HologramSubCommand {
 	@Override
 	public void execute(CommandSender sender, String label, String[] args) throws CommandException {
 		
-		CommandValidator.isTrue(!HolographicDisplays.is18orGreater(), "This command is no longer necessary in 1.8+. The holograms already use the correct ambient light.");
+		CommandValidator.isTrue(!MinecraftVersion.isGreaterEqualThan(MinecraftVersion.v1_8), "This command is no longer necessary in 1.8+. The holograms already use the correct ambient light.");
 		
 		NamedHologram hologram = NamedHologramManager.getHologram(args[0].toLowerCase());
 		CommandValidator.notNull(hologram, Strings.noSuchHologram(args[0].toLowerCase()));
@@ -70,7 +70,7 @@ public class FixCommand extends HologramSubCommand {
 	
 	@Override
 	public SubCommandType getType() {
-		if (HolographicDisplays.is18orGreater()) {
+		if (MinecraftVersion.isGreaterEqualThan(MinecraftVersion.v1_8)) {
 			return SubCommandType.HIDDEN;
 		} else {
 			return SubCommandType.GENERIC;

HolographicDisplays/Plugin/com/gmail/filoghost/holographicdisplays/object/line/CraftItemLine.java

@@ -13,6 +13,7 @@ import com.gmail.filoghost.holographicdisplays.api.line.ItemLine;
 import com.gmail.filoghost.holographicdisplays.nms.interfaces.entity.NMSEntityBase;
 import com.gmail.filoghost.holographicdisplays.nms.interfaces.entity.NMSItem;
 import com.gmail.filoghost.holographicdisplays.object.CraftHologram;
+import com.gmail.filoghost.holographicdisplays.util.MinecraftVersion;
 import com.gmail.filoghost.holographicdisplays.util.Offsets;
 import com.gmail.filoghost.holographicdisplays.util.Validator;
 
@@ -61,9 +62,9 @@ public class CraftItemLine extends CraftTouchableLine implements ItemLine {
 			
 			Location loc = nmsItem.getBukkitEntityNMS().getLocation();
 			
-			if (HolographicDisplays.is19orGreater()) {
+			if (MinecraftVersion.isGreaterEqualThan(MinecraftVersion.v1_9)) {
 				super.setTouchHandler(touchHandler, loc.getWorld(), loc.getX(), loc.getY() - getItemOffset(), loc.getZ());
-			} else if (HolographicDisplays.is18orGreater()) {
+			} else if (MinecraftVersion.isGreaterEqualThan(MinecraftVersion.v1_8)) {
 				super.setTouchHandler(touchHandler, loc.getWorld(), loc.getX(), loc.getY() - getItemOffset(), loc.getZ());
 			} else {
 				super.setTouchHandler(touchHandler, loc.getWorld(), loc.getX(), loc.getY() - getItemOffset(), loc.getZ());
@@ -84,7 +85,7 @@ public class CraftItemLine extends CraftTouchableLine implements ItemLine {
 			
 			nmsItem = HolographicDisplays.getNMSManager().spawnNMSItem(world, x, y + offset, z, this, itemStack);
 			
-			if (HolographicDisplays.is18orGreater()) {
+			if (MinecraftVersion.isGreaterEqualThan(MinecraftVersion.v1_8)) {
 				nmsVehicle = HolographicDisplays.getNMSManager().spawnNMSArmorStand(world, x, y + offset, z, this);
 			} else {
 				nmsVehicle = HolographicDisplays.getNMSManager().spawnNMSWitherSkull(world, x, y + offset, z, this);
@@ -150,9 +151,9 @@ public class CraftItemLine extends CraftTouchableLine implements ItemLine {
 	}
 	
 	private double getItemOffset() {
-		if (HolographicDisplays.is19orGreater()) {
+		if (MinecraftVersion.isGreaterEqualThan(MinecraftVersion.v1_9)) {
 			return Offsets.ARMOR_STAND_WITH_ITEM_1_9;
-		} else if (HolographicDisplays.is18orGreater()) {
+		} else if (MinecraftVersion.isGreaterEqualThan(MinecraftVersion.v1_8)) {
 			return Offsets.ARMOR_STAND_WITH_ITEM;
 		} else {
 			return Offsets.WITHER_SKULL_WITH_ITEM;

HolographicDisplays/Plugin/com/gmail/filoghost/holographicdisplays/object/line/CraftTextLine.java

@@ -12,6 +12,7 @@ import com.gmail.filoghost.holographicdisplays.nms.interfaces.entity.NMSEntityBa
 import com.gmail.filoghost.holographicdisplays.nms.interfaces.entity.NMSNameable;
 import com.gmail.filoghost.holographicdisplays.object.CraftHologram;
 import com.gmail.filoghost.holographicdisplays.placeholder.PlaceholdersManager;
+import com.gmail.filoghost.holographicdisplays.util.MinecraftVersion;
 import com.gmail.filoghost.holographicdisplays.util.Offsets;
 
 public class CraftTextLine extends CraftTouchableLine implements TextLine {
@@ -70,7 +71,7 @@ public class CraftTextLine extends CraftTouchableLine implements TextLine {
 	public void spawn(World world, double x, double y, double z) {
 		super.spawn(world, x, y, z);
 			
-		if (HolographicDisplays.is18orGreater()) {
+		if (MinecraftVersion.isGreaterEqualThan(MinecraftVersion.v1_8)) {
 			nmsNameble = HolographicDisplays.getNMSManager().spawnNMSArmorStand(world, x, y + getTextOffset(), z, this);
 		} else {
 			nmsNameble = HolographicDisplays.getNMSManager().spawnNMSHorse(world, x, y + Offsets.WITHER_SKULL_WITH_HORSE, z, this);
@@ -148,9 +149,9 @@ public class CraftTextLine extends CraftTouchableLine implements TextLine {
 	}
 
 	private double getTextOffset() {
-		if (HolographicDisplays.is19orGreater()) {
+		if (MinecraftVersion.isGreaterEqualThan(MinecraftVersion.v1_9)) {
 			return Offsets.ARMOR_STAND_ALONE_1_9;
-		} else if (HolographicDisplays.is18orGreater()) {
+		} else if (MinecraftVersion.isGreaterEqualThan(MinecraftVersion.v1_8)) {
 			return Offsets.ARMOR_STAND_ALONE;
 		} else {
 			return Offsets.WITHER_SKULL_WITH_HORSE;

HolographicDisplays/Plugin/com/gmail/filoghost/holographicdisplays/object/line/CraftTouchSlimeLine.java

@@ -6,6 +6,7 @@ import com.gmail.filoghost.holographicdisplays.HolographicDisplays;
 import com.gmail.filoghost.holographicdisplays.nms.interfaces.entity.NMSEntityBase;
 import com.gmail.filoghost.holographicdisplays.nms.interfaces.entity.NMSSlime;
 import com.gmail.filoghost.holographicdisplays.object.CraftHologram;
+import com.gmail.filoghost.holographicdisplays.util.MinecraftVersion;
 import com.gmail.filoghost.holographicdisplays.util.Offsets;
 
 /**
@@ -38,7 +39,7 @@ public class CraftTouchSlimeLine extends CraftHologramLine {
 		
 		nmsSlime = HolographicDisplays.getNMSManager().spawnNMSSlime(world, x, y + offset, z, this);
 		
-		if (HolographicDisplays.is18orGreater()) {
+		if (MinecraftVersion.isGreaterEqualThan(MinecraftVersion.v1_8)) {
 			nmsVehicle = HolographicDisplays.getNMSManager().spawnNMSArmorStand(world, x, y + offset, z, this);
 		} else {
 			nmsVehicle = HolographicDisplays.getNMSManager().spawnNMSWitherSkull(world, x, y + offset, z, this);
@@ -99,9 +100,9 @@ public class CraftTouchSlimeLine extends CraftHologramLine {
 	}
 	
 	private double getSlimeOffset() {
-		if (HolographicDisplays.is19orGreater()) {
+		if (MinecraftVersion.isGreaterEqualThan(MinecraftVersion.v1_9)) {
 			return Offsets.ARMOR_STAND_WITH_SLIME_1_9;
-		} else if (HolographicDisplays.is18orGreater()) {
+		} else if (MinecraftVersion.isGreaterEqualThan(MinecraftVersion.v1_8)) {
 			return Offsets.ARMOR_STAND_WITH_SLIME;
 		} else {
 			return Offsets.WITHER_SKULL_WITH_SLIME;

HolographicDisplays/Plugin/com/gmail/filoghost/holographicdisplays/util/MinecraftVersion.java

@@ -0,0 +1,45 @@
+package com.gmail.filoghost.holographicdisplays.util;
+
+/*
+ * Since 1.8 we use armor stands instead of wither skulls.
+ * Since 1.9 there is a different offset for the nametag.
+ * Since 1.10 there is a difference in the entity metadata packet index for items.
+ */
+public class MinecraftVersion {
+	
+	private static MinecraftVersion version;
+
+	public static final MinecraftVersion
+	
+		v1_7 = new MinecraftVersion(1),
+		
+		// Since 1.8 we use armor stands instead of wither skulls.
+		v1_8 = new MinecraftVersion(2),
+		
+		// Since 1.9 there is a different offset for the nametag.
+		v1_9 = new MinecraftVersion(3),
+		
+		// Since 1.10 there is a difference in the entity metadata packet index for items.
+		v1_10 = new MinecraftVersion(4);
+
+	private int value;
+	
+	private MinecraftVersion(int value) {
+		this.value = value;
+	}
+	
+	public static void set(MinecraftVersion version) {
+		if (version == null) {
+			throw new NullPointerException("version");
+		}
+		if (MinecraftVersion.version != null) {
+			throw new IllegalArgumentException("version already set");
+		}
+		MinecraftVersion.version = version;
+	}
+	
+	public static boolean isGreaterEqualThan(MinecraftVersion other) {
+		return MinecraftVersion.version.value >= other.value;
+	}
+	
+}

HolographicDisplays/Plugin/com/gmail/filoghost/holographicdisplays/util/VersionUtils.java

@@ -10,7 +10,6 @@ import org.bukkit.Bukkit;
 import org.bukkit.entity.EntityType;
 import org.bukkit.entity.Player;
 
-import com.gmail.filoghost.holographicdisplays.HolographicDisplays;
 import com.google.common.collect.ImmutableList;
 
 public class VersionUtils {
@@ -55,7 +54,7 @@ public class VersionUtils {
 	}
 	
 	public static boolean isArmorstand(EntityType type) {
-		if (!HolographicDisplays.is18orGreater()) {
+		if (!MinecraftVersion.isGreaterEqualThan(MinecraftVersion.v1_8)) {
 			return false;
 		}