From e12f258a33cc8963de141369b9600b727d8245f0 Mon Sep 17 00:00:00 2001
From: Rsl1122 <djrapitops@hotmail.com>
Date: Sat, 29 Sep 2018 13:21:54 +0300
Subject: [PATCH] [Debt] PlanAPI getInstance uses a static holder.

This is close to a Singleton pattern, but not quite. Testing required
to know impact of using static here. - Is it possible to set null?
---
 .../java/com/djrapitops/plan/api/CommonAPI.java     |  3 ++-
 .../main/java/com/djrapitops/plan/api/PlanAPI.java  | 13 +++++++++++--
 .../java/com/djrapitops/plan/system/PlanSystem.java |  6 ------
 3 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/Plan/src/main/java/com/djrapitops/plan/api/CommonAPI.java b/Plan/src/main/java/com/djrapitops/plan/api/CommonAPI.java
index 9f602e726..0f6ecd529 100644
--- a/Plan/src/main/java/com/djrapitops/plan/api/CommonAPI.java
+++ b/Plan/src/main/java/com/djrapitops/plan/api/CommonAPI.java
@@ -23,9 +23,10 @@ public abstract class CommonAPI implements PlanAPI {
     private final UUIDUtility uuidUtility;
     private final ErrorHandler errorHandler;
 
-    public CommonAPI(UUIDUtility uuidUtility, ErrorHandler errorHandler) {
+    CommonAPI(UUIDUtility uuidUtility, ErrorHandler errorHandler) {
         this.uuidUtility = uuidUtility;
         this.errorHandler = errorHandler;
+        PlanAPIHolder.set(this);
     }
 
     @Override
diff --git a/Plan/src/main/java/com/djrapitops/plan/api/PlanAPI.java b/Plan/src/main/java/com/djrapitops/plan/api/PlanAPI.java
index 739910c6b..465d51633 100644
--- a/Plan/src/main/java/com/djrapitops/plan/api/PlanAPI.java
+++ b/Plan/src/main/java/com/djrapitops/plan/api/PlanAPI.java
@@ -5,10 +5,10 @@
 package com.djrapitops.plan.api;
 
 import com.djrapitops.plan.data.plugin.PluginData;
-import com.djrapitops.plan.system.PlanSystem;
 import com.djrapitops.plan.system.database.databases.operation.FetchOperations;
 
 import java.util.Map;
+import java.util.Optional;
 import java.util.UUID;
 
 /**
@@ -19,7 +19,16 @@ import java.util.UUID;
 public interface PlanAPI {
 
     static PlanAPI getInstance() {
-        return PlanSystem.getInstance().getPlanAPI();
+        return Optional.ofNullable(PlanAPIHolder.API)
+                .orElseThrow(() -> new IllegalStateException("PlanAPI has not been initialised yet."));
+    }
+
+    class PlanAPIHolder {
+        static PlanAPI API;
+
+        static void set(PlanAPI api) {
+            PlanAPIHolder.API = api;
+        }
     }
 
     void addPluginDataSource(PluginData pluginData);
diff --git a/Plan/src/main/java/com/djrapitops/plan/system/PlanSystem.java b/Plan/src/main/java/com/djrapitops/plan/system/PlanSystem.java
index d2e295674..e702d5e01 100644
--- a/Plan/src/main/java/com/djrapitops/plan/system/PlanSystem.java
+++ b/Plan/src/main/java/com/djrapitops/plan/system/PlanSystem.java
@@ -4,7 +4,6 @@
  */
 package com.djrapitops.plan.system;
 
-import com.djrapitops.plan.PlanPlugin;
 import com.djrapitops.plan.api.PlanAPI;
 import com.djrapitops.plan.api.exceptions.EnableException;
 import com.djrapitops.plan.data.plugin.HookHandler;
@@ -97,11 +96,6 @@ public class PlanSystem implements SubSystem {
         this.errorHandler = errorHandler;
     }
 
-    @Deprecated
-    public static PlanSystem getInstance() {
-        return PlanPlugin.getInstance().getSystem();
-    }
-
     @Override
     public void enable() throws EnableException {
         enableSystems(