Some more test cleanup to not create so many threads. See #3320

akka-docs/rst/java/code/docs/extension/ExtensionDocTest.java

@@ -0,0 +1,81 @@
+/**
+ * Copyright (C) 2009-2013 Typesafe Inc. <http://www.typesafe.com>
+ */
+package docs.extension;
+
+//#imports
+import akka.actor.*;
+import java.util.concurrent.atomic.AtomicLong;
+
+//#imports
+
+import org.junit.Test;
+
+public class ExtensionDocTest {
+
+  static
+  //#extension
+  public class CountExtensionImpl implements Extension {
+    //Since this Extension is a shared instance
+    // per ActorSystem we need to be threadsafe
+    private final AtomicLong counter = new AtomicLong(0);
+
+    //This is the operation this Extension provides
+    public long increment() {
+      return counter.incrementAndGet();
+    }
+  }
+
+  //#extension
+
+  static
+  //#extensionid
+  public class CountExtension extends AbstractExtensionId<CountExtensionImpl>
+    implements ExtensionIdProvider {
+    //This will be the identifier of our CountExtension
+    public final static CountExtension CountExtensionProvider = new CountExtension();
+
+    //The lookup method is required by ExtensionIdProvider,
+    // so we return ourselves here, this allows us
+    // to configure our extension to be loaded when
+    // the ActorSystem starts up
+    public CountExtension lookup() {
+      return CountExtension.CountExtensionProvider; //The public static final
+    }
+
+    //This method will be called by Akka
+    // to instantiate our Extension
+    public CountExtensionImpl createExtension(ExtendedActorSystem system) {
+      return new CountExtensionImpl();
+    }
+  }
+
+  //#extensionid
+
+  static
+  //#extension-usage-actor
+  public class MyActor extends UntypedActor {
+    public void onReceive(Object msg) {
+      // typically you would use static import of the
+      // CountExtension.CountExtensionProvider field
+      CountExtension.CountExtensionProvider.get(getContext().system()).increment();
+    }
+  }
+
+  //#extension-usage-actor
+
+  @Test
+  public void demonstrateHowToCreateAndUseAnAkkaExtensionInJava() {
+    final ActorSystem system = null;
+    try {
+      //#extension-usage
+      // typically you would use static import of the
+      // CountExtension.CountExtensionProvider field
+      CountExtension.CountExtensionProvider.get(system).increment();
+      //#extension-usage
+    } catch (Exception e) {
+      //do nothing
+    }
+  }
+
+}