Add EnchantmentOffer to PrepareItemEnchantEvent

By: LukBukkit <luk.bukkit@gmail.com>

paper-api/src/main/java/org/bukkit/enchantments/EnchantmentOffer.java

@@ -0,0 +1,81 @@
+package org.bukkit.enchantments;
+
+import org.apache.commons.lang.Validate;
+
+/**
+ * A class for the available enchantment offers in the enchantment table.
+ */
+public class EnchantmentOffer {
+
+    private Enchantment enchantment;
+    private int enchantmentLevel;
+    private int cost;
+
+    public EnchantmentOffer(Enchantment enchantment, int enchantmentLevel, int cost) {
+        this.enchantment = enchantment;
+        this.enchantmentLevel = enchantmentLevel;
+        this.cost = cost;
+    }
+
+    /**
+     * Get the type of the enchantment.
+     *
+     * @return type of enchantment
+     */
+    public Enchantment getEnchantment() {
+        return enchantment;
+    }
+
+    /**
+     * Sets the type of the enchantment.
+     *
+     * @param enchantment type of the enchantment
+     */
+    public void setEnchantment(Enchantment enchantment) {
+        Validate.notNull(enchantment, "The enchantment may not be null!");
+
+        this.enchantment = enchantment;
+    }
+
+    /**
+     * Gets the level of the enchantment.
+     *
+     * @return level of the enchantment
+     */
+    public int getEnchantmentLevel() {
+        return enchantmentLevel;
+    }
+
+    /**
+     * Sets the level of the enchantment.
+     *
+     * @param enchantmentLevel level of the enchantment
+     */
+    public void setEnchantmentLevel(int enchantmentLevel) {
+        Validate.isTrue(enchantmentLevel > 0, "The enchantment level must be greater than 0!");
+
+        this.enchantmentLevel = enchantmentLevel;
+    }
+
+    /**
+     * Gets the cost in experience levels the player has to pay to enchant his
+     * item with this enchantment.
+     *
+     * @return cost for this enchantment
+     */
+    public int getCost() {
+        return cost;
+    }
+
+    /**
+     * Sets the cost in experience levels the player has to pay to enchant his
+     * item with this enchantment
+     *
+     * @param cost cost for this enchantment
+     */
+    public void setCost(int cost) {
+        Validate.isTrue(cost > 0, "The cost must be greater than 0!");
+
+        this.cost = cost;
+    }
+}