- Finished javadocs, annotations and null checkers in sign system.

api/src/main/java/com/hakan/core/HCore.java

@@ -172,7 +172,7 @@ public static HSign getSignByUID(UUID uid) {
         return HSignHandler.getByUID(uid);
     }
 
-    public static HSign createSign(Material type, String... lines) {
+    public static HSign createSign(@Nonnull Material type, @Nonnull String... lines) {
         return HSignHandler.create(type, lines);
     }
 

api/src/main/java/com/hakan/core/ui/sign/HSign.java

@@ -3,43 +3,100 @@
 import org.bukkit.Material;
 import org.bukkit.entity.Player;
 
+import javax.annotation.Nonnull;
+import java.util.Objects;
 import java.util.function.Consumer;
 
+/**
+ * HSign class to manage
+ * and show sign to player.
+ */
 public abstract class HSign {
 
     protected Material type;
     protected String[] lines;
     protected Consumer<String[]> consumer;
 
-    public HSign(Material type, String... lines) {
-        this.type = type;
-        this.lines = lines;
+    /**
+     * Creates new instance of this class.
+     *
+     * @param type  Type of sign.
+     * @param lines Lines of sign.
+     */
+    public HSign(@Nonnull Material type, @Nonnull String... lines) {
+        this.type = Objects.requireNonNull(type, "type cannot be null!");
+        this.lines = Objects.requireNonNull(lines, "lines cannot be null!");
     }
 
+    /**
+     * Gets type of sign.
+     *
+     * @return Type of sign.
+     */
+    @Nonnull
     public final Material getType() {
         return this.type;
     }
 
-    public final HSign setType(Material type) {
-        this.type = type;
+    /**
+     * Sets type of sign.
+     *
+     * @param type Type of sign.
+     * @return This class.
+     */
+    @Nonnull
+    public final HSign setType(@Nonnull Material type) {
+        this.type = Objects.requireNonNull(type, "type cannot be null!");
         return this;
     }
 
+    /**
+     * Gets line of sign.
+     *
+     * @return Lines of sign.
+     */
+    @Nonnull
     public final String[] getLines() {
         return this.lines;
     }
 
-    public final HSign setLines(String[] lines) {
-        this.lines = lines;
+    /**
+     * Sets lines of sign.
+     *
+     * @param lines Lines of sign.
+     * @return This class.
+     */
+    @Nonnull
+    public final HSign setLines(@Nonnull String[] lines) {
+        this.lines = Objects.requireNonNull(lines, "lines cannot be null!");
         return this;
     }
 
-    public final HSign onComplete(Consumer<String[]> consumer) {
-        this.consumer = consumer;
+    /**
+     * Runs when sign close.
+     *
+     * @param consumer Callback.
+     * @return This class.
+     */
+    @Nonnull
+    public final HSign onComplete(@Nonnull Consumer<String[]> consumer) {
+        this.consumer = Objects.requireNonNull(consumer, "complete consumer cannot be null!");
         return this;
     }
 
-    public abstract void open(Player player);
+    /**
+     * Opens the sign to player.
+     *
+     * @param player Player.
+     */
+    public abstract void open(@Nonnull Player player);
 
-    public abstract <T> void listen(Player player, T packet);
+    /**
+     * Listens player packet if
+     * packet is a sign packet.
+     *
+     * @param player Player.
+     * @param packet Packet.
+     */
+    public abstract <T> void listen(@Nonnull Player player, @Nonnull T packet);
 }

api/src/main/java/com/hakan/core/ui/sign/HSignHandler.java

@@ -3,59 +3,132 @@
 import com.hakan.core.HCore;
 import com.hakan.core.listener.HListenerAdapter;
 import com.hakan.core.ui.sign.listeners.HSignListener;
+import org.apache.commons.lang.Validate;
 import org.bukkit.Material;
 import org.bukkit.entity.Player;
 import org.bukkit.plugin.java.JavaPlugin;
 
+import javax.annotation.Nonnull;
 import java.util.*;
 
-public class HSignHandler {
+/**
+ * HSignHandler class to find
+ * and create the signs.
+ */
+public final class HSignHandler {
 
     private static final Map<UUID, HSign> signMap = new HashMap<>();
 
-    public static void initialize(JavaPlugin plugin) {
+    /**
+     * Initializes sign system.
+     *
+     * @param plugin Main class of plugin.
+     */
+    public static void initialize(@Nonnull JavaPlugin plugin) {
         HListenerAdapter.register(new HSignListener(plugin));
     }
 
-
+    /**
+     * Gets content as safe.
+     *
+     * @return Content.
+     */
+    @Nonnull
     public static Map<UUID, HSign> getContentSafe() {
         return new HashMap<>(HSignHandler.signMap);
     }
 
+    /**
+     * Gets content.
+     *
+     * @return Content
+     */
+    @Nonnull
     public static Map<UUID, HSign> getContent() {
         return HSignHandler.signMap;
     }
 
+    /**
+     * Gets values as safe.
+     *
+     * @return Values.
+     */
+    @Nonnull
     public static Collection<HSign> getValuesSafe() {
         return new ArrayList<>(HSignHandler.signMap.values());
     }
 
+    /**
+     * Gets values.
+     *
+     * @return Values.
+     */
+    @Nonnull
     public static Collection<HSign> getValues() {
         return HSignHandler.signMap.values();
     }
 
-    public static Optional<HSign> findByPlayer(Player player) {
+    /**
+     * Finds HSign by player.
+     *
+     * @param player Player.
+     * @return HSign as optional.
+     */
+    @Nonnull
+    public static Optional<HSign> findByPlayer(@Nonnull Player player) {
         return HSignHandler.findByUID(player.getUniqueId());
     }
 
-    public static HSign getByPlayer(Player player) {
+    /**
+     * Gets HSign by player.
+     *
+     * @param player Player.
+     * @return HSign.
+     */
+    @Nonnull
+    public static HSign getByPlayer(@Nonnull Player player) {
         return HSignHandler.findByPlayer(player).orElseThrow(() -> new NullPointerException("this player doesn't have a inventory!"));
     }
 
-    public static Optional<HSign> findByUID(UUID uid) {
-        return Optional.ofNullable(HSignHandler.signMap.get(uid));
+    /**
+     * Finds HSign by player UID.
+     *
+     * @param uid Player UID.
+     * @return HSign as optional.
+     */
+    @Nonnull
+    public static Optional<HSign> findByUID(@Nonnull UUID uid) {
+        return Optional.ofNullable(HSignHandler.signMap.get(Objects.requireNonNull(uid, "UID cannot be null!")));
     }
 
-    public static HSign getByUID(UUID uid) {
+    /**
+     * Gets HSign by player UID.
+     *
+     * @param uid Player UID.
+     * @return HSign.
+     */
+    @Nonnull
+    public static HSign getByUID(@Nonnull UUID uid) {
         return HSignHandler.findByUID(uid).orElseThrow(() -> new NullPointerException("this player doesn't have a inventory!"));
     }
 
-    public static HSign create(Material type, String... lines) {
+    /**
+     * Creates HSign.
+     *
+     * @param type  Sign type as Material.
+     * @param lines Lines of sign.
+     * @return Created HSign.
+     */
+    @Nonnull
+    public static HSign create(@Nonnull Material type, @Nonnull String... lines) {
+        Validate.notNull(type, "type cannot be null!");
+        Validate.notNull(lines, "lines cannot be null!");
+
         try {
             return (HSign) Class.forName("com.hakan.core.ui.sign.wrapper.HSign_" + HCore.getVersionString())
                     .getConstructor(Material.class, String[].class).newInstance(type, lines);
         } catch (Exception e) {
-            return null;
+            throw new NullPointerException(e.getMessage());
         }
     }
 }

api/src/main/java/com/hakan/core/ui/sign/listeners/HSignListener.java

@@ -8,14 +8,27 @@
 
 import javax.annotation.Nonnull;
 
-public class HSignListener extends HListenerAdapter {
+/**
+ * HSignListener class.
+ */
+public final class HSignListener extends HListenerAdapter {
 
+    /**
+     * Creates new instance of this class.
+     *
+     * @param plugin Main class of plugin.
+     */
     public HSignListener(@Nonnull JavaPlugin plugin) {
         super(plugin);
     }
 
+    /**
+     * Packet event.
+     *
+     * @param event Event.
+     */
     @EventHandler
-    public void onPacketEvent(PacketEvent event) {
+    public void onPacketEvent(@Nonnull PacketEvent event) {
         if (event.getPacket().toString().contains("PacketPlayInUpdateSign")) {
             HSignHandler.findByPlayer(event.getPlayer())
                     .ifPresent(hSign -> hSign.listen(event.getPlayer(), event.getPacket()));

nms/1_10_R1/src/main/java/com/hakan/core/ui/sign/wrapper/HSign_v1_10_R1.java

@@ -4,13 +4,16 @@
 import com.hakan.core.ui.sign.HSign;
 import com.hakan.core.ui.sign.HSignHandler;
 import net.minecraft.server.v1_10_R1.*;
+import org.apache.commons.lang.Validate;
 import org.bukkit.Material;
 import org.bukkit.block.Block;
 import org.bukkit.craftbukkit.v1_10_R1.CraftWorld;
 import org.bukkit.craftbukkit.v1_10_R1.block.CraftSign;
 import org.bukkit.craftbukkit.v1_10_R1.util.CraftMagicNumbers;
 import org.bukkit.entity.Player;
 
+import javax.annotation.Nonnull;
+
 /**
  * {@inheritDoc}
  */
@@ -19,15 +22,16 @@ public final class HSign_v1_10_R1 extends HSign {
     /**
      * {@inheritDoc}
      */
-    public HSign_v1_10_R1(Material type, String... lines) {
+    public HSign_v1_10_R1(@Nonnull Material type, @Nonnull String... lines) {
         super(type, lines);
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
-    public void open(Player player) {
+    public void open(@Nonnull Player player) {
+        Validate.notNull(player, "player cannot be null!");
         BlockPosition blockPosition = new BlockPosition(player.getLocation().getBlockX(), 1, player.getLocation().getBlockZ());
 
         PacketPlayOutBlockChange packet = new PacketPlayOutBlockChange(((CraftWorld) player.getWorld()).getHandle(), blockPosition);
@@ -48,7 +52,9 @@ public void open(Player player) {
      * {@inheritDoc}
      */
     @Override
-    public <T> void listen(Player player, T packet) {
+    public <T> void listen(@Nonnull Player player, @Nonnull T packet) {
+        Validate.notNull(player, "player cannot be null!");
+        Validate.notNull(packet, "packet cannot be null!");
         PacketPlayInUpdateSign packetPlayInUpdateSign = (PacketPlayInUpdateSign) packet;
 
         BlockPosition position = packetPlayInUpdateSign.a();

nms/1_11_R1/src/main/java/com/hakan/core/ui/sign/wrapper/HSign_v1_11_R1.java

@@ -4,13 +4,16 @@
 import com.hakan.core.ui.sign.HSign;
 import com.hakan.core.ui.sign.HSignHandler;
 import net.minecraft.server.v1_11_R1.*;
+import org.apache.commons.lang.Validate;
 import org.bukkit.Material;
 import org.bukkit.block.Block;
 import org.bukkit.craftbukkit.v1_11_R1.CraftWorld;
 import org.bukkit.craftbukkit.v1_11_R1.block.CraftSign;
 import org.bukkit.craftbukkit.v1_11_R1.util.CraftMagicNumbers;
 import org.bukkit.entity.Player;
 
+import javax.annotation.Nonnull;
+
 /**
  * {@inheritDoc}
  */
@@ -19,15 +22,16 @@ public final class HSign_v1_11_R1 extends HSign {
     /**
      * {@inheritDoc}
      */
-    public HSign_v1_11_R1(Material type, String... lines) {
+    public HSign_v1_11_R1(@Nonnull Material type, @Nonnull String... lines) {
         super(type, lines);
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
-    public void open(Player player) {
+    public void open(@Nonnull Player player) {
+        Validate.notNull(player, "player cannot be null!");
         BlockPosition blockPosition = new BlockPosition(player.getLocation().getBlockX(), 1, player.getLocation().getBlockZ());
 
         PacketPlayOutBlockChange packet = new PacketPlayOutBlockChange(((CraftWorld) player.getWorld()).getHandle(), blockPosition);
@@ -48,7 +52,9 @@ public void open(Player player) {
      * {@inheritDoc}
      */
     @Override
-    public <T> void listen(Player player, T packet) {
+    public <T> void listen(@Nonnull Player player, @Nonnull T packet) {
+        Validate.notNull(player, "player cannot be null!");
+        Validate.notNull(packet, "packet cannot be null!");
         PacketPlayInUpdateSign packetPlayInUpdateSign = (PacketPlayInUpdateSign) packet;
 
         BlockPosition position = packetPlayInUpdateSign.a();