From f2ba3018808e536b52a115f2c14b0dd2bfba6565 Mon Sep 17 00:00:00 2001
From: Risto Lahtela <24460436+Rsl1122@users.noreply.github.com>
Date: Thu, 19 Mar 2020 15:56:29 +0200
Subject: [PATCH] Made CapabilityService more resilient

Affects issues:
- Fixed #1356
---
 .../plan/capability/CapabilityService.java    | 23 ++++++----------
 .../plan/capability/CapabilitySvc.java        | 27 +------------------
 2 files changed, 9 insertions(+), 41 deletions(-)

diff --git a/Plan/api/src/main/java/com/djrapitops/plan/capability/CapabilityService.java b/Plan/api/src/main/java/com/djrapitops/plan/capability/CapabilityService.java
index 0f41b0c3b..e75b04be9 100644
--- a/Plan/api/src/main/java/com/djrapitops/plan/capability/CapabilityService.java
+++ b/Plan/api/src/main/java/com/djrapitops/plan/capability/CapabilityService.java
@@ -16,7 +16,8 @@
  */
 package com.djrapitops.plan.capability;
 
-import java.util.Optional;
+import java.util.ArrayList;
+import java.util.List;
 import java.util.function.Consumer;
 
 /**
@@ -39,8 +40,7 @@ public interface CapabilityService {
      * @throws IllegalStateException If Plan is installed, but not enabled.
      */
     static CapabilityService getInstance() {
-        return Optional.ofNullable(Holder.service)
-                .orElseThrow(() -> new IllegalStateException("CapabilityService has not been initialised yet."));
+        return new CapabilityService() {};
     }
 
     /**
@@ -48,7 +48,9 @@ public interface CapabilityService {
      *
      * @param isEnabledListener The boolean given to the method tells if Plan has enabled successfully.
      */
-    void registerEnableListener(Consumer<Boolean> isEnabledListener);
+    default void registerEnableListener(Consumer<Boolean> isEnabledListener) {
+        ListHolder.ENABLE_LISTENERS.add(isEnabledListener);
+    }
 
     /**
      * Check if the API on the current version provides a capability.
@@ -61,16 +63,7 @@ public interface CapabilityService {
         return Capability.getByName(capabilityName).isPresent();
     }
 
-    class Holder {
-        static CapabilityService service;
-
-        private Holder() {
-            /* Static variable holder */
-        }
-
-        static void set(CapabilityService service) {
-            Holder.service = service;
-        }
+    class ListHolder {
+        static List<Consumer<Boolean>> ENABLE_LISTENERS = new ArrayList<>();
     }
-
 }
diff --git a/Plan/common/src/main/java/com/djrapitops/plan/capability/CapabilitySvc.java b/Plan/common/src/main/java/com/djrapitops/plan/capability/CapabilitySvc.java
index 193a74453..946ec142c 100644
--- a/Plan/common/src/main/java/com/djrapitops/plan/capability/CapabilitySvc.java
+++ b/Plan/common/src/main/java/com/djrapitops/plan/capability/CapabilitySvc.java
@@ -16,8 +16,6 @@
  */
 package com.djrapitops.plan.capability;
 
-import java.util.ArrayList;
-import java.util.List;
 import java.util.function.Consumer;
 
 /**
@@ -29,32 +27,9 @@ import java.util.function.Consumer;
  */
 public class CapabilitySvc implements CapabilityService {
 
-    private final List<Consumer<Boolean>> enableListeners;
-
-    private CapabilitySvc() {
-        Holder.set(this);
-        enableListeners = new ArrayList<>();
-    }
-
-    private static CapabilitySvc get() {
-        if (Holder.service == null) {
-            return new CapabilitySvc();
-        }
-        return (CapabilitySvc) Holder.service;
-    }
-
-    public static void initialize() {
-        get();
-    }
-
     public static void notifyAboutEnable(boolean isEnabled) {
-        for (Consumer<Boolean> enableListener : get().enableListeners) {
+        for (Consumer<Boolean> enableListener : CapabilityService.ListHolder.ENABLE_LISTENERS) {
             enableListener.accept(isEnabled);
         }
     }
-
-    @Override
-    public void registerEnableListener(Consumer<Boolean> enableListener) {
-        enableListeners.add(enableListener);
-    }
 }
\ No newline at end of file