Move stuff into commons, rename PermissionObject, add more javadocs to api

api/src/main/java/me/lucko/luckperms/LuckPerms.java

@@ -4,14 +4,22 @@ import lombok.AccessLevel;
 import lombok.NoArgsConstructor;
 import me.lucko.luckperms.api.LuckPermsApi;
 
+import java.util.Optional;
+
 /**
  * Static access to LuckPerms
  */
 @NoArgsConstructor(access = AccessLevel.PRIVATE)
-public class LuckPerms {
+public final class LuckPerms {
 
     private static LuckPermsApi api = null;
 
+
+    /**
+     * Gets an instance of {@link LuckPermsApi}
+     * @return an api instance
+     * @throws IllegalStateException if the api is not loaded
+     */
     public static LuckPermsApi getApi() {
         if (api == null) {
             throw new IllegalStateException("API is not loaded.");
@@ -19,6 +27,15 @@ public class LuckPerms {
         return api;
     }
 
+    /**
+     * Gets an instance of {@link LuckPermsApi} safely. Unlike {@link LuckPerms#getApi}, this method will not throw an
+     * {@link IllegalStateException} if the api is not loaded, rather return an empty {@link Optional}.
+     * @return an optional api instance
+     */
+    public static Optional<LuckPermsApi> getApiSafe() {
+        return Optional.ofNullable(api);
+    }
+
     static void registerProvider(LuckPermsApi luckPermsApi) {
         api = luckPermsApi;
     }