src/de/steamwar/linkage/LinkageProcessor.java

@@ -294,6 +294,7 @@ public class LinkageProcessor extends AbstractProcessor {
         MaxVersion maxVersion = typeElement.getAnnotation(MaxVersion.class);
         EventMode eventMode = typeElement.getAnnotation(EventMode.class);
         DiscordMode discordMode = typeElement.getAnnotation(DiscordMode.class);
+        PluginCheck[] pluginChecks = typeElement.getAnnotationsByType(PluginCheck.class);
         if (context == LinkageType.Context.SPIGOT) {
             errorOnNonNull(typeElement, eventMode, discordMode);
             if (minVersion != null) {
@@ -304,7 +305,14 @@ public class LinkageProcessor extends AbstractProcessor {
                 buildPlan.addImport("de.steamwar.core.Core");
                 stringConsumer.accept("if (Core.getVersion() < " + maxVersion.value() + ") {");
             }
+            if (pluginChecks.length != 0) {
+                buildPlan.addImport("org.bukkit.Bukkit");
+                stringConsumer.accept(Arrays.stream(pluginChecks).map(pluginCheck -> {
+                    return "Bukkit.getPluginManager().getPlugin(\"" + pluginCheck.value() + "\") " + (pluginCheck.has() == PluginCheck.Has.THIS ? "=" : "!") + "= null";
+                }).collect(Collectors.joining(" && ", "if (", ") {")));
+            }
             inner.run();
+            if (pluginChecks.length != 0) stringConsumer.accept("}");
             if (maxVersion != null) stringConsumer.accept("}");
             if (minVersion != null) stringConsumer.accept("}");
         } else {
@@ -317,7 +325,14 @@ public class LinkageProcessor extends AbstractProcessor {
                 buildPlan.addImport("de.steamwar.bungeecore.bot.config.SteamwarDiscordBotConfig");
                 stringConsumer.accept("if (SteamwarDiscordBotConfig.loaded) {");
             }
+            if (pluginChecks.length != 0) {
+                buildPlan.addImport("net.md_5.bungee.BungeeCord");
+                stringConsumer.accept(Arrays.stream(pluginChecks).map(pluginCheck -> {
+                    return "BungeeCord.getPluginManager().getPlugin(\"" + pluginCheck.value() + "\") " + (pluginCheck.has() == PluginCheck.Has.THIS ? "=" : "!") + "= null";
+                }).collect(Collectors.joining(" && ", "if (", ") {")));
+            }
             inner.run();
+            if (pluginChecks.length != 0) stringConsumer.accept("}");
             if (discordMode != null) stringConsumer.accept("}");
             if (eventMode != null) stringConsumer.accept("}");
         }

src/de/steamwar/linkage/PluginCheck.java

@@ -0,0 +1,42 @@
+/*
+ * This file is a part of the SteamWar software.
+ *
+ * Copyright (C) 2022  SteamWar.de-Serverteam
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package de.steamwar.linkage;
+
+import java.lang.annotation.*;
+
+@AllowedContexts({LinkageType.Context.BUNGEE, LinkageType.Context.SPIGOT})
+@Retention(RetentionPolicy.SOURCE)
+@Target({ElementType.TYPE})
+@Repeatable(PluginCheck.PluginChecks.class)
+public @interface PluginCheck {
+    Has has() default Has.THIS;
+    String value();
+
+    enum Has {
+        THIS,
+        NOT
+    }
+
+    @Retention(RetentionPolicy.SOURCE)
+    @Target({ElementType.TYPE})
+    @interface PluginChecks {
+        @SuppressWarnings("unused") PluginCheck[] value() default {};
+    }
+}