Added icon (Material) to hooks

src/main/java/world/bentobox/bentobox/api/hooks/Hook.java

@@ -1,7 +1,9 @@
 package world.bentobox.bentobox.api.hooks;
 
 import org.bukkit.Bukkit;
+import org.bukkit.Material;
 import org.bukkit.plugin.Plugin;
+import org.eclipse.jdt.annotation.NonNull;
 import org.eclipse.jdt.annotation.Nullable;
 
 /**
@@ -9,24 +11,35 @@ import org.eclipse.jdt.annotation.Nullable;
  */
 public abstract class Hook {
 
-    private String pluginName;
+    private @NonNull String pluginName;
+    private @NonNull Material icon;
 
-    public Hook(String pluginName) {
+    public Hook(@NonNull String pluginName, @NonNull Material icon) {
-        if (pluginName == null || pluginName.isEmpty()) {
+        if (pluginName.isEmpty()) {
-            throw new IllegalArgumentException("Plugin name cannot be null nor empty.");
+            throw new IllegalArgumentException("Plugin name cannot be empty.");
         }
         this.pluginName = pluginName;
+        this.icon = icon;
     }
 
     /**
      * Returns the name of the plugin related to this Hook.
-     * Cannot be null.
      * @return the plugin name.
      */
+    @NonNull
     public String getPluginName() {
         return pluginName;
     }
 
+    /**
+     * Returns the icon representing this Hook.
+     * @return the icon.
+     */
+    @NonNull
+    public Material getIcon() {
+        return icon;
+    }
+
     /**
      * Returns the Plugin instance related to this Hook or null if it could not be found.
      * @return the Plugin instance of the plugin this Hook hooks into.

src/main/java/world/bentobox/bentobox/hooks/MultiverseCoreHook.java

@@ -1,8 +1,8 @@
 package world.bentobox.bentobox.hooks;
 
 import org.bukkit.Bukkit;
+import org.bukkit.Material;
 import org.bukkit.World;
-
 import world.bentobox.bentobox.BentoBox;
 import world.bentobox.bentobox.api.hooks.Hook;
 
@@ -17,7 +17,7 @@ public class MultiverseCoreHook extends Hook {
     private static final String MULTIVERSE_IMPORT = "mv import ";
 
     public MultiverseCoreHook() {
-        super("Multiverse-Core");
+        super("Multiverse-Core", Material.COMPASS);
     }
 
     public void registerWorld(World world) {

src/main/java/world/bentobox/bentobox/hooks/PlaceholderAPIHook.java

@@ -1,5 +1,6 @@
 package world.bentobox.bentobox.hooks;
 
+import org.bukkit.Material;
 import org.eclipse.jdt.annotation.NonNull;
 import world.bentobox.bentobox.BentoBox;
 import world.bentobox.bentobox.api.addons.Addon;
@@ -22,7 +23,7 @@ public class PlaceholderAPIHook extends Hook {
     private Map<Addon, AddonPlaceholderExpansion> addonsExpansions;
 
     public PlaceholderAPIHook() {
-        super("PlaceholderAPI");
+        super("PlaceholderAPI", Material.PAPER);
         this.addonsExpansions = new HashMap<>();
     }
 

src/main/java/world/bentobox/bentobox/hooks/VaultHook.java

@@ -1,10 +1,10 @@
 package world.bentobox.bentobox.hooks;
 
-import org.bukkit.Bukkit;
-import org.bukkit.plugin.RegisteredServiceProvider;
-
 import net.milkbowl.vault.economy.Economy;
 import net.milkbowl.vault.economy.EconomyResponse;
+import org.bukkit.Bukkit;
+import org.bukkit.Material;
+import org.bukkit.plugin.RegisteredServiceProvider;
 import world.bentobox.bentobox.api.hooks.Hook;
 import world.bentobox.bentobox.api.user.User;
 
@@ -17,7 +17,7 @@ public class VaultHook extends Hook {
     private Economy economy;
 
     public VaultHook() {
-        super("Vault");
+        super("Vault", Material.GOLD_NUGGET);
     }
 
     @Override

src/main/java/world/bentobox/bentobox/managers/HooksManager.java

@@ -1,12 +1,13 @@
 package world.bentobox.bentobox.managers;
 
+import org.eclipse.jdt.annotation.NonNull;
+import world.bentobox.bentobox.BentoBox;
+import world.bentobox.bentobox.api.hooks.Hook;
+
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Optional;
 
-import world.bentobox.bentobox.BentoBox;
-import world.bentobox.bentobox.api.hooks.Hook;
-
 /**
  * @author Poslovitch
  */
@@ -20,7 +21,7 @@ public class HooksManager {
         this.hooks = new ArrayList<>();
     }
 
-    public void registerHook(Hook hook) {
+    public void registerHook(@NonNull Hook hook) {
         if (hook.isPluginAvailable()) {
             plugin.log("Hooking with " + hook.getPluginName() + "...");
             if (hook.hook()) {