!htp #18919 #19519 New JavaDSL for Akka HTTP (#20518)

* !htt #18919 #19519 Align Java HTTP server DSL with Scala

This commits replaces the Java HTTP server DSL with a Java-8 centric one
which exposes all scala DSL concepts to be usable from Java, including
custom directives, (un)marshallers, rejections, headers, and type safety
for path and query parameters.

* Add RequestContext and RouteResult to Java DSL
fix websockets
WIP bring java docs up to date.
This applies some updates to the root-level documentation

* [htp] Fix java documentation to correctly mention timeouts

Timeouts are configured the same in Java and Scala. Hence, linking to the
scala docs for timeouts from Java.

* =htc fix optionalHeaderValueByType in Java

* =htt #20200 fix java testkit always using NoLogging instead logger

* +htt actually run new javadsl tests, allow overriding config

* =htt improve javadsl test infra with more details when fails

* =htt fix bug in wrong path matcher exposed

* +htp add missing remaining path matcher

* =htp Java DSL cookie tests fixed

* =htt Java DSL ParameterDirectivesTest fixed

Protect the tweets from scalariform

Incorrect response expectations in cache condition directives spec fixed

* =htt Path directives for Java DSL

* +!htt PathMatchers rewritten, made uniform and tests passing

* Bugfix in java reject and a little test-boyscouting

* Revert "Incorrect response expectations in cache condition directives spec fixed"

This reverts commit cd50e89d45db010309f8249b090ea654ebb11c7a.

* +htc HttpAPIsTest is compile time only, not for running
Also, moved from the client package since not strictly a client test.

SecurityDirectives passing

Two faulty tests and two actual bugs.

Fix for cache condition spec not working

* Not sending in Unit instad of the implicit magnet in the test
* HeaderMagnet now works as expected
* Java API added for - and + on DateTime

PetStore example and test fixed

* Annotations to make marshalling work without default constructor
* Made model class immutable

Incorrect tests fixed

Some scaladoc boyscouting as bonus

* =htt RequestValTest sprinkled out across multiple directive tests

Client ip extraction test with incorrect header name fixed.

* =htt Incorrect CodingDirectivesTest fixed.

* =htt Bugfix for Java Unmarshaller.firstOf and fixes to JavaRouteTest

* =htt MarshallerTest fixed

* Missing seal signature added to JavaDSL
* More consistent (with Scala) test kit setup for Java
* missing Javadocs added
* Thread.sleep in default exception handler removed

* =htt copy directive docs, prepare for finishing it up

* +htt SecurityDirectives.authorize variants and test coverage added

* +htt Custom headers in Java DSL

* =htt WIP on java docs

* +htp add missing parameterOrDefault directive
Fixed a lot of doc warnings

* =htc intense progress on javadsl docs

* =htc #20470 Link to issue about docs and fix compile error
compile, migration guide
don't mima check http-experimental

* =htt Java DSL doc warnings fixed.
Only `Could not lex literal_block` ones left now

* =htc fix mima settings

* =doc fix MethodDirectives doc test with custom method

* =htc fix coding directives spec after bad merge

* =htc fix concat being corresponding to route() in javadsl

* =htt Disable consistency check for route/concat as it fails only on ci server

* !htt Minor fixes to PathMatchers

akka-http-tests/src/test/java/akka/http/javadsl/server/JavaTestServer.java

@@ -0,0 +1,122 @@
+/*
+ * Copyright (C) 2009-2016 Lightbend Inc. <http://www.lightbend.com>
+ */
+package akka.http.javadsl.server;
+
+import akka.actor.ActorSystem;
+import akka.http.javadsl.ConnectHttp;
+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.StatusCodes;
+import akka.stream.ActorMaterializer;
+import akka.stream.javadsl.Flow;
+import scala.concurrent.duration.Duration;
+import scala.runtime.BoxedUnit;
+
+import java.util.Optional;
+import java.util.concurrent.*;
+import java.util.function.Function;
+
+public class JavaTestServer extends AllDirectives { // or import static Directives.*;
+
+  public Route createRoute() {
+    final Duration timeout = Duration.create(1, TimeUnit.SECONDS);
+
+    final Route index = path("", () ->
+        withRequestTimeout(timeout, this::mkTimeoutResponse, () -> {
+          silentSleep(5000); // too long, trigger failure
+          return complete(index());
+        })
+      );
+
+    final Function<Optional<ProvidedCredentials>, Optional<String>> handleAuth = (maybeCreds) -> {
+      if (maybeCreds.isPresent() && maybeCreds.get().verify("pa$$word")) // some secure hash + check
+        return Optional.of(maybeCreds.get().identifier());
+      else return Optional.empty();
+    };
+
+    final Route secure = path("secure", () ->
+        authenticateBasic("My basic secure site", handleAuth, (login) ->
+          complete(String.format("Hello, %s!", login))
+        )
+      );
+
+    final Route ping = path("ping", () ->
+      complete("PONG!")
+      );
+
+    final Route crash = path("crash", () ->
+      path("scala", () -> completeWithFutureString(akka.dispatch.Futures.<String>failed(new Exception("Boom!")))).orElse(
+      path("java", () -> completeWithFutureString(CompletableFuture.<String>supplyAsync(() -> { throw new RuntimeException("Boom!"); }))))
+    );
+
+    final Route inner = path("inner", () ->
+      getFromResourceDirectory("someDir")
+    );
+
+
+    return get(() ->
+      index.orElse(secure).orElse(ping).orElse(crash).orElse(inner)
+    );
+  }
+
+  private void silentSleep(int millis) {
+    try {
+      Thread.sleep(millis);
+    } catch (InterruptedException e) {
+      throw new RuntimeException(e);
+    }
+  }
+
+  private HttpResponse mkTimeoutResponse(HttpRequest request) {
+    return HttpResponse.create()
+      .withStatus(StatusCodes.ENHANCE_YOUR_CALM)
+      .withEntity("Unable to serve response within time limit, please enchance your calm.");
+  }
+
+  private String index() {
+    return "    <html>\n" +
+      "      <body>\n" +
+      "        <h1>Say hello to <i>akka-http-core</i>!</h1>\n" +
+      "        <p>Defined resources:</p>\n" +
+      "        <ul>\n" +
+      "          <li><a href=\"/ping\">/ping</a></li>\n" +
+      "          <li><a href=\"/secure\">/secure</a> Use any username and '&lt;username&gt;-password' as credentials</li>\n" +
+      "          <li><a href=\"/crash\">/crash</a></li>\n" +
+      "        </ul>\n" +
+      "      </body>\n" +
+      "    </html>\n";
+  }
+
+  public static void main(String[] args) throws InterruptedException {
+    final JavaTestServer server = new JavaTestServer();
+    server.run();
+  }
+
+  private void run() throws InterruptedException {
+    final ActorSystem system = ActorSystem.create();
+    final ActorMaterializer mat = ActorMaterializer.create(system);
+
+    final Flow<HttpRequest, HttpResponse, ?> flow = createRoute().flow(system, mat);
+    final CompletionStage<ServerBinding> binding =
+      Http.get(system).bindAndHandle(flow, ConnectHttp.toHost("127.0.0.1"), mat);
+
+    System.console().readLine("Press [ENTER] to quit...");
+    shutdown(binding);
+  }
+
+  private CompletionStage<Void> shutdown(CompletionStage<ServerBinding> binding) {
+    return binding.thenAccept(b -> {
+      System.out.println(String.format("Unbinding from %s", b.localAddress()));
+
+      final CompletionStage<BoxedUnit> unbound = b.unbind();
+      try {
+        unbound.toCompletableFuture().get(3, TimeUnit.SECONDS); // block...
+      } catch (TimeoutException | InterruptedException | ExecutionException e) {
+        throw new RuntimeException(e);
+      }
+    });
+  }
+}