More methods & annotation

src/main/java/net/minestom/server/item/Item.java

@@ -2,10 +2,12 @@ package net.minestom.server.item;
 
 import net.kyori.adventure.text.Component;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import java.util.List;
 import java.util.function.Consumer;
 import java.util.function.IntUnaryOperator;
+import java.util.function.UnaryOperator;
 
 public class Item {
 
@@ -14,7 +16,8 @@ public class Item {
     private final Component displayName;
     private final List<Component> lore;
 
-    protected Item(Material material, int amount, Component displayName, List<Component> lore) {
+    protected Item(@NotNull Material material, int amount,
+                   @Nullable Component displayName, @Nullable List<Component> lore) {
         this.material = material;
         this.amount = amount;
         this.displayName = displayName;
@@ -26,6 +29,7 @@ public class Item {
         return new ItemBuilder(material);
     }
 
+    @NotNull
     public ItemBuilder builder() {
         return new ItemBuilder(material)
                 .amount(amount)
@@ -54,11 +58,33 @@ public class Item {
         return withAmount(intUnaryOperator.applyAsInt(amount));
     }
 
+    @Nullable
     public Component getDisplayName() {
         return displayName;
     }
 
+    @NotNull
+    public Item withDisplayName(@Nullable Component displayName) {
+        return builder().displayName(displayName).build();
+    }
+
+    @NotNull
+    public Item withDisplayName(@NotNull UnaryOperator<@Nullable Component> componentUnaryOperator) {
+        return withDisplayName(componentUnaryOperator.apply(displayName));
+    }
+
+    @Nullable
     public List<Component> getLore() {
         return lore;
     }
+
+    @NotNull
+    public Item withLore(@Nullable List<@NotNull Component> lore) {
+        return builder().lore(lore).build();
+    }
+
+    @NotNull
+    public Item withLore(@NotNull UnaryOperator<@Nullable List<Component>> loreUnaryOperator) {
+        return withLore(loreUnaryOperator.apply(lore));
+    }
 }

src/main/java/net/minestom/server/item/ItemBuilder.java

@@ -9,36 +9,42 @@ import java.util.List;
 
 public class ItemBuilder {
 
+    private final Material material;
     private int amount;
     private Component displayName;
     private List<Component> lore;
 
     protected ItemBuilder(@NotNull Material material) {
-
+        this.material = material;
+        this.amount = 0;
     }
 
+    @NotNull
     public ItemBuilder amount(int amount) {
         this.amount = amount;
         return this;
     }
 
+    @NotNull
     public ItemBuilder displayName(Component displayName) {
         this.displayName = displayName;
         return this;
     }
 
+    @NotNull
     public ItemBuilder lore(List<Component> lore) {
         this.lore = Collections.unmodifiableList(lore);
         return this;
     }
 
+    @NotNull
     public ItemBuilder lore(Component... lore) {
         return lore(Arrays.asList(lore));
     }
 
     @NotNull
     public Item build() {
-        return null; // TODO
+        return new Item(material, amount, displayName, lore);
     }
 
 }