feat(plugin): implement IGamePlugin loading in SDK

Author: xeruf

helpers/test-client/src/sc/TestClient.java

@@ -42,7 +42,7 @@
 public class TestClient extends XStreamClient {
   private static final Logger logger = (Logger) LoggerFactory.getLogger(TestClient.class);
 
-  private static final String gameType = ServiceLoader.load(IGamePlugin.class).iterator().next().id();
+  private static final String gameType = IGamePlugin.loadPluginId();
   private static final ClientPlayer[] players = {new ClientPlayer(), new ClientPlayer()};
   private static final File logDir = new File("log").getAbsoluteFile();
 

sdk/src/server-api/sc/api/plugins/IGamePlugin.kt

@@ -2,13 +2,27 @@ package sc.api.plugins
 
 import sc.plugins.IPlugin
 import sc.shared.ScoreDefinition
-import java.io.File
+import java.util.ServiceLoader
 
 interface IGamePlugin: IPlugin {
-    fun id(): String?
+    fun id(): String
     /** @return eine neues Spiel dieses Typs. */
     fun createGame(): IGameInstance
     fun createGameFromState(state: IGameState): IGameInstance
 
     val scoreDefinition: ScoreDefinition
+    
+    companion object {
+        @JvmStatic
+        fun loadPlugin(): IGamePlugin {
+            val iter = ServiceLoader.load(IGamePlugin::class.java).iterator()
+            if (!iter.hasNext())
+                throw RuntimeException("Couldn't find a plugin!")
+            return iter.next()
+        }
+        
+        @JvmStatic
+        fun loadPluginId(): String =
+                loadPlugin().id()
+    }
 }