Add methods to check conflicting enchantments. Adds BUKKIT-3830

src/main/java/org/bukkit/craftbukkit/inventory/CraftMetaEnchantedBook.java

@@ -161,4 +161,8 @@ class CraftMetaEnchantedBook extends CraftMetaItem implements EnchantmentStorage
     public boolean hasStoredEnchants() {
         return !(enchantments == null || enchantments.isEmpty());
     }
+
+    public boolean hasConflictingStoredEnchant(Enchantment ench) {
+        return checkConflictingEnchants(enchantments, ench);
+    }
 }

src/main/java/org/bukkit/craftbukkit/inventory/CraftMetaItem.java

@@ -405,6 +405,10 @@ class CraftMetaItem implements ItemMeta, Repairable {
         return !(enchantments == null || enchantments.isEmpty());
     }
 
+    public boolean hasConflictingEnchant(Enchantment ench) {
+        return checkConflictingEnchants(enchantments, ench);
+    }
+
     public List<String> getLore() {
         return this.lore == null ? null : new ArrayList<String>(this.lore);
     }
@@ -555,6 +559,20 @@ class CraftMetaItem implements ItemMeta, Repairable {
         }
     }
 
+    static boolean checkConflictingEnchants(Map<Enchantment, Integer> enchantments, Enchantment ench) {
+        if (enchantments == null || enchantments.isEmpty()) {
+            return false;
+        }
+
+        for (Enchantment enchant : enchantments.keySet()) {
+            if (enchant.conflictsWith(ench)) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
     @Override
     public final String toString() {
         return SerializableMeta.classMap.get(getClass()) + "_META:" + serialize(); // TODO: cry

src/test/java/org/bukkit/craftbukkit/inventory/ItemMetaTest.java

@@ -21,6 +21,7 @@ import org.bukkit.inventory.meta.BookMeta;
 import org.bukkit.inventory.meta.EnchantmentStorageMeta;
 import org.bukkit.inventory.meta.FireworkEffectMeta;
 import org.bukkit.inventory.meta.FireworkMeta;
+import org.bukkit.inventory.meta.ItemMeta;
 import org.bukkit.inventory.meta.LeatherArmorMeta;
 import org.bukkit.inventory.meta.MapMeta;
 import org.bukkit.inventory.meta.PotionMeta;
@@ -62,6 +63,52 @@ public class ItemMetaTest extends AbstractTestingBase {
         }
     }
 
+    @Test
+    public void testConflictingEnchantment() {
+        ItemMeta itemMeta = Bukkit.getItemFactory().getItemMeta(Material.DIAMOND_PICKAXE);
+        assertThat(itemMeta.hasConflictingEnchant(Enchantment.DURABILITY), is(false));
+
+        itemMeta.addEnchant(Enchantment.SILK_TOUCH, 1, false);
+        assertThat(itemMeta.hasConflictingEnchant(Enchantment.DURABILITY), is(false));
+        assertThat(itemMeta.hasConflictingEnchant(Enchantment.LOOT_BONUS_BLOCKS), is(true));
+        assertThat(itemMeta.hasConflictingEnchant(null), is(false));
+    }
+
+    @Test
+    public void testConflictingStoredEnchantment() {
+        EnchantmentStorageMeta itemMeta = (EnchantmentStorageMeta) Bukkit.getItemFactory().getItemMeta(Material.ENCHANTED_BOOK);
+        assertThat(itemMeta.hasConflictingStoredEnchant(Enchantment.DURABILITY), is(false));
+
+        itemMeta.addStoredEnchant(Enchantment.SILK_TOUCH, 1, false);
+        assertThat(itemMeta.hasConflictingStoredEnchant(Enchantment.DURABILITY), is(false));
+        assertThat(itemMeta.hasConflictingStoredEnchant(Enchantment.LOOT_BONUS_BLOCKS), is(true));
+        assertThat(itemMeta.hasConflictingStoredEnchant(null), is(false));
+    }
+
+    @Test
+    public void testConflictingEnchantments() {
+        ItemMeta itemMeta = Bukkit.getItemFactory().getItemMeta(Material.DIAMOND_PICKAXE);
+        itemMeta.addEnchant(Enchantment.DURABILITY, 6, true);
+        itemMeta.addEnchant(Enchantment.DIG_SPEED, 6, true);
+        assertThat(itemMeta.hasConflictingEnchant(Enchantment.LOOT_BONUS_BLOCKS), is(false));
+
+        itemMeta.addEnchant(Enchantment.SILK_TOUCH, 1, false);
+        assertThat(itemMeta.hasConflictingEnchant(Enchantment.LOOT_BONUS_BLOCKS), is(true));
+        assertThat(itemMeta.hasConflictingEnchant(null), is(false));
+    }
+
+    @Test
+    public void testConflictingStoredEnchantments() {
+        EnchantmentStorageMeta itemMeta = (EnchantmentStorageMeta) Bukkit.getItemFactory().getItemMeta(Material.ENCHANTED_BOOK);
+        itemMeta.addStoredEnchant(Enchantment.DURABILITY, 6, true);
+        itemMeta.addStoredEnchant(Enchantment.DIG_SPEED, 6, true);
+        assertThat(itemMeta.hasConflictingStoredEnchant(Enchantment.LOOT_BONUS_BLOCKS), is(false));
+
+        itemMeta.addStoredEnchant(Enchantment.SILK_TOUCH, 1, false);
+        assertThat(itemMeta.hasConflictingStoredEnchant(Enchantment.LOOT_BONUS_BLOCKS), is(true));
+        assertThat(itemMeta.hasConflictingStoredEnchant(null), is(false));
+    }
+
     private static FireworkMeta newFireworkMeta() {
         return ((FireworkMeta) Bukkit.getItemFactory().getItemMeta(Material.FIREWORK));
     }