Plan API 5.2-R0.3: ListenerService

Allows registering listeners for platforms that don't have static
accessors for registering listeners, such as Velocity

Plan/api/build.gradle

@@ -4,7 +4,7 @@ dependencies {
     compileOnly "com.google.code.gson:gson:$gsonVersion"
 }
 
-ext.apiVersion = '5.2-R0.2'
+ext.apiVersion = '5.2-R0.3'
 
 publishing {
     repositories {

Plan/api/src/main/java/com/djrapitops/plan/settings/ListenerService.java

@@ -0,0 +1,65 @@
+/*
+ *  This file is part of Player Analytics (Plan).
+ *
+ *  Plan is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU Lesser General Public License v3 as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  Plan is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public License
+ *  along with Plan. If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.djrapitops.plan.settings;
+
+import java.util.Optional;
+import java.util.concurrent.atomic.AtomicReference;
+
+/**
+ * Service for registering listeners as Plan.
+ * <p>
+ * This is an utility service for implementing listeners for platforms that don't have
+ * static access to the listener registration.
+ */
+public interface ListenerService {
+
+    /**
+     * Obtain instance of ListenerService.
+     *
+     * @return QueryService implementation.
+     * @throws NoClassDefFoundError  If Plan is not installed and this class can not be found or if older Plan version is installed.
+     * @throws IllegalStateException If Plan is installed, but not enabled.
+     */
+    static ListenerService getInstance() {
+        return Optional.ofNullable(ListenerService.Holder.service.get())
+                .orElseThrow(() -> new IllegalStateException("ListenerService has not been initialised yet."));
+    }
+
+    /**
+     * Attempts to register an event listener to the platform as Plan.
+     * <p>
+     * This is an utility method for implementing listeners for platforms that don't have
+     * static access to the listener registration.
+     * <p>
+     * The listener needs to fulfill the qualities required by the platform.
+     *
+     * @param listener listener object.
+     */
+    void registerListenerForPlan(Object listener);
+
+    class Holder {
+        static final AtomicReference<ListenerService> service = new AtomicReference<>();
+
+        private Holder() {
+            /* Static variable holder */
+        }
+
+        static void set(ListenerService service) {
+            ListenerService.Holder.service.set(service);
+        }
+    }
+}

Plan/common/src/main/java/com/djrapitops/plan/PlanSystem.java

@@ -31,6 +31,7 @@ import com.djrapitops.plan.identification.ServerInfo;
 import com.djrapitops.plan.processing.Processing;
 import com.djrapitops.plan.query.QuerySvc;
 import com.djrapitops.plan.settings.ConfigSystem;
+import com.djrapitops.plan.settings.ListenerSvc;
 import com.djrapitops.plan.settings.SettingsSvc;
 import com.djrapitops.plan.settings.locale.LocaleSystem;
 import com.djrapitops.plan.storage.database.DBSystem;
@@ -75,6 +76,7 @@ public class PlanSystem implements SubSystem {
     private final ResourceSvc resourceService;
     private final ExtensionSvc extensionService;
     private final QuerySvc queryService;
+    private final ListenerSvc listenerService;
     private final SettingsSvc settingsService;
     private final PluginLogger logger;
     private final ErrorLogger errorLogger;
@@ -99,6 +101,7 @@ public class PlanSystem implements SubSystem {
             ResourceSvc resourceService,
             ExtensionSvc extensionService,
             QuerySvc queryService,
+            ListenerSvc listenerService,
             SettingsSvc settingsService,
             PluginLogger logger,
             ErrorLogger errorLogger,
@@ -122,6 +125,7 @@ public class PlanSystem implements SubSystem {
         this.resourceService = resourceService;
         this.extensionService = extensionService;
         this.queryService = queryService;
+        this.listenerService = listenerService;
         this.settingsService = settingsService;
         this.logger = logger;
         this.errorLogger = errorLogger;
@@ -144,6 +148,7 @@ public class PlanSystem implements SubSystem {
         extensionService.register();
         resolverService.register();
         resourceService.register();
+        listenerService.register();
         settingsService.register();
         queryService.register();
 

Plan/common/src/main/java/com/djrapitops/plan/settings/ListenerSvc.java

@@ -0,0 +1,42 @@
+/*
+ *  This file is part of Player Analytics (Plan).
+ *
+ *  Plan is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU Lesser General Public License v3 as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  Plan is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public License
+ *  along with Plan. If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.djrapitops.plan.settings;
+
+import net.playeranalytics.plugin.server.Listeners;
+
+import javax.inject.Inject;
+import javax.inject.Singleton;
+
+@Singleton
+public class ListenerSvc implements ListenerService {
+
+    private final Listeners listeners;
+
+    @Inject
+    public ListenerSvc(Listeners listeners) {
+        this.listeners = listeners;
+    }
+
+    @Override
+    public void registerListenerForPlan(Object listener) {
+        listeners.registerListener(listener);
+    }
+
+    public void register() {
+        Holder.set(this);
+    }
+}