+doc #18012 add Java-side Server Websocket documentation

akka-docs-dev/rst/java/code/docs/http/javadsl/server/WebsocketCoreExample.java

@@ -0,0 +1,96 @@
+/*
+ * Copyright (C) 2009-2015 Typesafe Inc. <http://www.typesafe.com>
+ */
+
+package docs.http.javadsl.server;
+
+//#websocket-example-using-core
+import java.io.BufferedReader;
+import java.io.InputStreamReader;
+import java.util.concurrent.TimeUnit;
+
+import scala.concurrent.Await;
+import scala.concurrent.Future;
+import scala.concurrent.duration.FiniteDuration;
+import scala.runtime.BoxedUnit;
+
+import akka.japi.Function;
+import akka.japi.JavaPartialFunction;
+
+import akka.stream.ActorMaterializer;
+import akka.stream.Materializer;
+import akka.stream.javadsl.Flow;
+import akka.stream.javadsl.Source;
+
+import akka.actor.ActorSystem;
+import akka.http.javadsl.Http;
+import akka.http.javadsl.ServerBinding;
+import akka.http.javadsl.model.HttpRequest;
+import akka.http.javadsl.model.HttpResponse;
+import akka.http.javadsl.model.ws.Message;
+import akka.http.javadsl.model.ws.TextMessage;
+import akka.http.javadsl.model.ws.Websocket;
+
+public class WebsocketCoreExample {
+    //#websocket-handling
+    public static HttpResponse handleRequest(HttpRequest request) {
+        System.out.println("Handling request to " + request.getUri());
+
+        if (request.getUri().path().equals("/greeter"))
+            return Websocket.handleWebsocketRequestWith(request, greeter());
+        else
+            return HttpResponse.create().withStatus(404);
+    }
+    //#websocket-handling
+
+    public static void main(String[] args) throws Exception {
+        ActorSystem system = ActorSystem.create();
+
+        try {
+            final Materializer materializer = ActorMaterializer.create(system);
+
+            Future<ServerBinding> serverBindingFuture =
+                Http.get(system).bindAndHandleSync(
+                    new Function<HttpRequest, HttpResponse>() {
+                        public HttpResponse apply(HttpRequest request) throws Exception {
+                            return handleRequest(request);
+                        }
+                    }, "localhost", 8080, materializer);
+
+            // will throw if binding fails
+            Await.result(serverBindingFuture, new FiniteDuration(1, TimeUnit.SECONDS));
+            System.out.println("Press ENTER to stop.");
+            new BufferedReader(new InputStreamReader(System.in)).readLine();
+        } finally {
+            system.shutdown();
+        }
+    }
+
+    //#websocket-handler
+    /**
+     * A handler that treats incoming messages as a name,
+     * and responds with a greeting to that name
+     */
+    public static Flow<Message, Message, BoxedUnit> greeter() {
+        return
+            Flow.<Message>create()
+                .collect(new JavaPartialFunction<Message, Message>() {
+                    @Override
+                    public Message apply(Message msg, boolean isCheck) throws Exception {
+                        if (isCheck)
+                            if (msg.isText()) return null;
+                            else throw noMatch();
+                        else
+                            return handleTextMessage(msg.asTextMessage());
+                    }
+                });
+    }
+    public static TextMessage handleTextMessage(TextMessage msg) {
+        if (msg.isStrict()) // optimization that directly creates a simple response...
+            return TextMessage.create("Hello "+msg.getStrictText());
+        else // ... this would suffice to handle all text messages in a streaming fashion
+            return TextMessage.create(Source.single("Hello ").concat(msg.getStreamedText()));
+    }
+    //#websocket-handler
+}
+//#websocket-example-using-core

akka-docs-dev/rst/java/code/docs/http/javadsl/server/WebsocketRoutingExample.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright (C) 2009-2015 Typesafe Inc. <http://www.typesafe.com>
+ */
+
+package docs.http.javadsl.server;
+
+import akka.http.javadsl.server.Route;
+
+import akka.japi.JavaPartialFunction;
+
+import akka.stream.javadsl.Flow;
+import akka.stream.javadsl.Source;
+
+import akka.http.javadsl.model.ws.Message;
+import akka.http.javadsl.model.ws.TextMessage;
+
+import akka.http.javadsl.server.HttpApp;
+
+public class WebsocketRoutingExample extends HttpApp {
+    //#websocket-route
+    @Override
+    public Route createRoute() {
+        return
+            path("greeter").route(
+                handleWebsocketMessages(greeter())
+            );
+    }
+    //#websocket-route
+
+    /**
+     * A handler that treats incoming messages as a name,
+     * and responds with a greeting to that name
+     */
+    public static Flow<Message, Message, Object> greeter() {
+        return
+            upcastMaterializerToObject(Flow.<Message>create())
+                .collect(new JavaPartialFunction<Message, Message>() {
+                    @Override
+                    public Message apply(Message msg, boolean isCheck) throws Exception {
+                        if (isCheck)
+                            if (msg.isText()) return null;
+                            else throw noMatch();
+                        else
+                            return handleTextMessage(msg.asTextMessage());
+                    }
+                });
+    }
+    public static TextMessage handleTextMessage(TextMessage msg) {
+        if (msg.isStrict()) // optimization that directly creates a simple response...
+            return TextMessage.create("Hello "+msg.getStrictText());
+        else // ... this would suffice to handle all text messages in a streaming fashion
+            return TextMessage.create(Source.single("Hello ").concat(msg.getStreamedText()));
+    }
+
+    // needed because of #18028, see https://github.com/akka/akka/issues/18028
+    @SuppressWarnings("unchecked")
+    public static <T, U> Flow<T, U, Object> upcastMaterializerToObject(Flow< T, U, ?> flow) {
+        return (Flow<T, U, Object>) flow;
+    }
+}