SPIGOT-2540: Add nullability annotations to entire Bukkit API

By: Darkyenus <darkyenus@gmail.com>

paper-api/src/main/java/org/bukkit/entity/AreaEffectCloud.java

@@ -7,6 +7,8 @@ import org.bukkit.potion.PotionData;
 import org.bukkit.potion.PotionEffect;
 import org.bukkit.potion.PotionEffectType;
 import org.bukkit.projectiles.ProjectileSource;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 /**
  * Represents an area effect cloud which will imbue a potion effect onto
@@ -123,6 +125,7 @@ public interface AreaEffectCloud extends Entity {
      *
      * @return particle the set particle type
      */
+    @NotNull
     Particle getParticle();
 
     /**
@@ -130,7 +133,7 @@ public interface AreaEffectCloud extends Entity {
      *
      * @param particle the new particle type
      */
-    void setParticle(Particle particle);
+    void setParticle(@NotNull Particle particle);
 
     /**
      * Sets the particle which this cloud will be composed of
@@ -139,20 +142,21 @@ public interface AreaEffectCloud extends Entity {
      * @param data the data to use for the particle or null,
      *             the type of this depends on {@link Particle#getDataType()}
      */
-    <T> void setParticle(Particle particle, T data);
+    <T> void setParticle(@NotNull Particle particle, @Nullable T data);
 
     /**
      * Sets the underlying potion data
      *
      * @param data PotionData to set the base potion state to
      */
-    void setBasePotionData(PotionData data);
+    void setBasePotionData(@NotNull PotionData data);
 
     /**
      * Returns the potion data about the base potion
      *
      * @return a PotionData object
      */
+    @NotNull
     PotionData getBasePotionData();
 
     /**
@@ -171,6 +175,7 @@ public interface AreaEffectCloud extends Entity {
      *
      * @return the immutable list of custom potion effects
      */
+    @NotNull
     List<PotionEffect> getCustomEffects();
 
     /**
@@ -181,7 +186,7 @@ public interface AreaEffectCloud extends Entity {
      * overwritten
      * @return true if the effect was added as a result of this call
      */
-    boolean addCustomEffect(PotionEffect effect, boolean overwrite);
+    boolean addCustomEffect(@NotNull PotionEffect effect, boolean overwrite);
 
     /**
      * Removes a custom potion effect from this cloud.
@@ -189,7 +194,7 @@ public interface AreaEffectCloud extends Entity {
      * @param type the potion effect type to remove
      * @return true if the an effect was removed as a result of this call
      */
-    boolean removeCustomEffect(PotionEffectType type);
+    boolean removeCustomEffect(@NotNull PotionEffectType type);
 
     /**
      * Checks for a specific custom potion effect type on this cloud.
@@ -197,7 +202,7 @@ public interface AreaEffectCloud extends Entity {
      * @param type the potion effect type to check for
      * @return true if the potion has this effect
      */
-    boolean hasCustomEffect(PotionEffectType type);
+    boolean hasCustomEffect(@Nullable PotionEffectType type);
 
     /**
      * Removes all custom potion effects from this cloud.
@@ -209,6 +214,7 @@ public interface AreaEffectCloud extends Entity {
      *
      * @return cloud color
      */
+    @NotNull
     Color getColor();
 
     /**
@@ -216,13 +222,14 @@ public interface AreaEffectCloud extends Entity {
      *
      * @param color cloud color
      */
-    void setColor(Color color);
+    void setColor(@NotNull Color color);
 
     /**
      * Retrieve the original source of this cloud.
      * 
      * @return the {@link ProjectileSource} that threw the LingeringPotion
      */
+    @Nullable
     public ProjectileSource getSource();
 
     /**
@@ -230,5 +237,5 @@ public interface AreaEffectCloud extends Entity {
      *
      * @param source the {@link ProjectileSource} that threw the LingeringPotion
      */
-    public void setSource(ProjectileSource source);
+    public void setSource(@Nullable ProjectileSource source);
 }