Add null-related annotations to the API

api/src/main/java/me/filoghost/holographicdisplays/api/Hologram.java

@@ -11,6 +11,8 @@ import me.filoghost.holographicdisplays.api.line.TextLine;
 import org.bukkit.Location;
 import org.bukkit.World;
 import org.bukkit.inventory.ItemStack;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 /**
  * An object made of various lines, that can be items or holograms.
@@ -28,7 +30,8 @@ public interface Hologram {
      * @return the new TextLine appended
      * @since 1
      */
-    TextLine appendTextLine(String text);
+    @NotNull
+    TextLine appendTextLine(@Nullable String text);
     
     
     /**
@@ -38,7 +41,8 @@ public interface Hologram {
      * @return the new ItemLine appended
      * @since 1
      */
-    ItemLine appendItemLine(ItemStack itemStack);
+    @NotNull
+    ItemLine appendItemLine(@NotNull ItemStack itemStack);
     
     
     /**
@@ -51,7 +55,8 @@ public interface Hologram {
      * @throws IndexOutOfBoundsException if the index is out of range (index < 0 || index >= size())
      * @since 1
      */
-    TextLine insertTextLine(int index, String text);
+    @NotNull
+    TextLine insertTextLine(int index, @Nullable String text);
     
     
     /**
@@ -64,7 +69,8 @@ public interface Hologram {
      * @throws IndexOutOfBoundsException if the index is out of range (index < 0 || index >= size())
      * @since 1
      */
-    ItemLine insertItemLine(int index, ItemStack itemStack);
+    @NotNull
+    ItemLine insertItemLine(int index, @NotNull ItemStack itemStack);
     
     
     /**
@@ -75,6 +81,7 @@ public interface Hologram {
      * @throws IndexOutOfBoundsException if the index is out of range (index < 0 || index >= size())
      * @since 1
      */
+    @NotNull
     HologramLine getLine(int index);
     
     /**
@@ -119,7 +126,7 @@ public interface Hologram {
      * @param location the new location
      * @since 1
      */
-    void teleport(Location location);
+    void teleport(@NotNull Location location);
     
     
     /**
@@ -132,7 +139,7 @@ public interface Hologram {
      * @param z the Z coordinate
      * @since 1
      */
-    void teleport(World world, double x, double y, double z);
+    void teleport(@NotNull World world, double x, double y, double z);
     
     /**
      * Returns the position of the hologram.
@@ -140,6 +147,7 @@ public interface Hologram {
      * @return the Location of the hologram
      * @since 1
      */
+    @NotNull
     Location getLocation();
     
     /**
@@ -175,6 +183,7 @@ public interface Hologram {
      * @return the world of the hologram
      * @since 1
      */
+    @NotNull
     World getWorld();
     
     
@@ -186,6 +195,7 @@ public interface Hologram {
      * @return the VisibilityManager of this hologram
      * @since 1
      */
+    @NotNull
     VisibilityManager getVisibilityManager();
     
     

api/src/main/java/me/filoghost/holographicdisplays/api/HolographicDisplaysAPI.java

@@ -10,6 +10,7 @@ import me.filoghost.holographicdisplays.api.placeholder.PlaceholderReplacer;
 import org.bukkit.Location;
 import org.bukkit.entity.Entity;
 import org.bukkit.plugin.Plugin;
+import org.jetbrains.annotations.NotNull;
 
 import java.util.Collection;
 
@@ -39,7 +40,8 @@ public interface HolographicDisplaysAPI {
         return 1;
     }
 
-    static HolographicDisplaysAPI get(Plugin plugin) {
+    @NotNull
+    static HolographicDisplaysAPI get(@NotNull Plugin plugin) {
         return HolographicDisplaysAPIProvider.getImplementation().getHolographicDisplaysAPI(plugin);
     }
 
@@ -50,7 +52,8 @@ public interface HolographicDisplaysAPI {
      * @return the created hologram
      * @since 1
      */
-    Hologram createHologram(Location source);
+    @NotNull
+    Hologram createHologram(@NotNull Location source);
 
     /**
      * Returns all the active holograms. A hologram is no longer active after {@link Hologram#delete()} is invoked.
@@ -58,12 +61,13 @@ public interface HolographicDisplaysAPI {
      * @return an immutable collection of active holograms
      * @since 1
      */
+    @NotNull
     Collection<Hologram> getHolograms();
 
     /**
      * @since 1
      */
-    void registerPlaceholder(String identifier, int refreshIntervalTicks, PlaceholderReplacer replacer);
+    void registerPlaceholder(@NotNull String identifier, int refreshIntervalTicks, @NotNull PlaceholderReplacer replacer);
 
     /**
      * Returns all the registered placeholder identifiers.
@@ -71,6 +75,7 @@ public interface HolographicDisplaysAPI {
      * @return a collection of placeholder identifiers
      * @since 1
      */
+    @NotNull
     Collection<String> getRegisteredPlaceholders();
 
     /**
@@ -79,7 +84,7 @@ public interface HolographicDisplaysAPI {
      * @param identifier the identifier of the placeholder to remove
      * @since 1
      */
-    void unregisterPlaceholder(String identifier);
+    void unregisterPlaceholder(@NotNull String identifier);
 
     /**
      * Resets and removes all the registered placeholders.
@@ -97,7 +102,7 @@ public interface HolographicDisplaysAPI {
      * @return if the entity is part of a hologram
      * @since 1
      */
-    static boolean isHologramEntity(Entity entity) {
+    static boolean isHologramEntity(@NotNull Entity entity) {
         return HolographicDisplaysAPIProvider.getImplementation().isHologramEntity(entity);
     }
 

api/src/main/java/me/filoghost/holographicdisplays/api/VisibilityManager.java

@@ -6,6 +6,7 @@
 package me.filoghost.holographicdisplays.api;
 
 import org.bukkit.entity.Player;
+import org.jetbrains.annotations.NotNull;
 
 /**
  * This object is used to manage the visibility of a hologram.
@@ -41,7 +42,7 @@ public interface VisibilityManager {
      * @param player the involved player
      * @since 1
      */
-    void showTo(Player player);
+    void showTo(@NotNull Player player);
     
     /**
      * Hides the hologram to a player, overriding the value of {@link #isVisibleByDefault()}.
@@ -50,7 +51,7 @@ public interface VisibilityManager {
      * @param player the involved player
      * @since 1
      */
-    void hideTo(Player player);
+    void hideTo(@NotNull Player player);
     
     /**
      * Checks if a hologram is visible to a player.
@@ -59,7 +60,7 @@ public interface VisibilityManager {
      * @return if the player can see the hologram
      * @since 1
      */
-    boolean isVisibleTo(Player player);
+    boolean isVisibleTo(@NotNull Player player);
     
     /**
      * Resets the visibility to the default value. If you previously called {@link #showTo(Player)}
@@ -69,7 +70,7 @@ public interface VisibilityManager {
      * @param player the involved player
      * @since 1
      */
-    void resetVisibility(Player player);
+    void resetVisibility(@NotNull Player player);
     
     /**
      * Resets the visibility for all the players. See {@link #resetVisibility(Player)} for more details.

api/src/main/java/me/filoghost/holographicdisplays/api/handler/PickupHandler.java

@@ -6,6 +6,7 @@
 package me.filoghost.holographicdisplays.api.handler;
 
 import org.bukkit.entity.Player;
+import org.jetbrains.annotations.NotNull;
 
 /**
  * Interface to handle items being picked up by players.
@@ -19,6 +20,6 @@ public interface PickupHandler {
      * @param player the player who picked up the item
      * @since 1
      */
-    void onPickup(Player player);
+    void onPickup(@NotNull Player player);
     
 }

api/src/main/java/me/filoghost/holographicdisplays/api/handler/TouchHandler.java

@@ -6,6 +6,7 @@
 package me.filoghost.holographicdisplays.api.handler;
 
 import org.bukkit.entity.Player;
+import org.jetbrains.annotations.NotNull;
 
 /**
  * Interface to handle touch holograms.
@@ -19,6 +20,6 @@ public interface TouchHandler {
      * @param player the player who interacts
      * @since 1
      */
-    void onTouch(Player player);
+    void onTouch(@NotNull Player player);
     
 }

api/src/main/java/me/filoghost/holographicdisplays/api/line/CollectableLine.java

@@ -6,6 +6,7 @@
 package me.filoghost.holographicdisplays.api.line;
 
 import me.filoghost.holographicdisplays.api.handler.PickupHandler;
+import org.jetbrains.annotations.Nullable;
 
 /**
  * A line of a Hologram that can be picked up.
@@ -20,7 +21,7 @@ public interface CollectableLine extends HologramLine {
      * @param pickupHandler the new PickupHandler, can be null.
      * @since 1
      */
-    void setPickupHandler(PickupHandler pickupHandler);
+    void setPickupHandler(@Nullable PickupHandler pickupHandler);
     
     /**
      * Returns the current PickupHandler of this line.
@@ -28,6 +29,7 @@ public interface CollectableLine extends HologramLine {
      * @return the current PickupHandler, can be null.
      * @since 1
      */
+    @Nullable
     PickupHandler getPickupHandler();
     
 }

api/src/main/java/me/filoghost/holographicdisplays/api/line/HologramLine.java

@@ -6,6 +6,7 @@
 package me.filoghost.holographicdisplays.api.line;
 
 import me.filoghost.holographicdisplays.api.Hologram;
+import org.jetbrains.annotations.NotNull;
 
 /**
  * Interface to represent a line in a Hologram.
@@ -20,6 +21,7 @@ public interface HologramLine {
      * @return the parent Hologram.
      * @since 1
      */
+    @NotNull
     Hologram getParent();
     
     /**

api/src/main/java/me/filoghost/holographicdisplays/api/line/ItemLine.java

@@ -6,6 +6,7 @@
 package me.filoghost.holographicdisplays.api.line;
 
 import org.bukkit.inventory.ItemStack;
+import org.jetbrains.annotations.NotNull;
 
 /**
  * @since 1
@@ -18,6 +19,7 @@ public interface ItemLine extends CollectableLine, TouchableLine {
      * @return the ItemStack if this ItemLine.
      * @since 1
      */
+    @NotNull
     ItemStack getItemStack();
 
     /**
@@ -26,6 +28,6 @@ public interface ItemLine extends CollectableLine, TouchableLine {
      * @param itemStack the new item, should not be null.
      * @since 1
      */
-    void setItemStack(ItemStack itemStack);
+    void setItemStack(@NotNull ItemStack itemStack);
     
 }

api/src/main/java/me/filoghost/holographicdisplays/api/line/TextLine.java

@@ -5,6 +5,8 @@
  */
 package me.filoghost.holographicdisplays.api.line;
 
+import org.jetbrains.annotations.Nullable;
+
 /**
  * @since 1
  */
@@ -16,6 +18,7 @@ public interface TextLine extends TouchableLine {
      * @return the current text of this line.
      * @since 1
      */
+    @Nullable
     String getText();
     
     /**
@@ -24,6 +27,6 @@ public interface TextLine extends TouchableLine {
      * @param text the new text of this line.
      * @since 1
      */
-    void setText(String text);
+    void setText(@Nullable String text);
     
 }

api/src/main/java/me/filoghost/holographicdisplays/api/line/TouchableLine.java

@@ -6,6 +6,7 @@
 package me.filoghost.holographicdisplays.api.line;
 
 import me.filoghost.holographicdisplays.api.handler.TouchHandler;
+import org.jetbrains.annotations.Nullable;
 
 /**
  * A line of a Hologram that can be touched (right click).
@@ -20,7 +21,7 @@ public interface TouchableLine extends HologramLine {
      * @param touchHandler the new TouchHandler, can be null.
      * @since 1
      */
-    void setTouchHandler(TouchHandler touchHandler);
+    void setTouchHandler(@Nullable TouchHandler touchHandler);
     
     /**
      * Returns the current TouchHandler of this line.
@@ -28,6 +29,7 @@ public interface TouchableLine extends HologramLine {
      * @return the current TouchHandler, can be null.
      * @since 1
      */
+    @Nullable
     TouchHandler getTouchHandler();
     
 }

api/src/main/java/me/filoghost/holographicdisplays/api/placeholder/PlaceholderFactory.java

@@ -15,6 +15,7 @@ public interface PlaceholderFactory {
     /**
      * @since 1
      */
+    @Nullable
     Placeholder getPlaceholder(@Nullable String argument);
     
 }

api/src/main/java/me/filoghost/holographicdisplays/api/placeholder/PlaceholderReplacer.java

@@ -25,6 +25,7 @@ public interface PlaceholderReplacer {
      * @return the placeholder replacement
      * @since 1
      */
+    @Nullable
     String getReplacement(@Nullable String argument);
 
 }