move jdk9 source code (#1976)

* move jdk9 source code

* Update Events.scala

* javafmt

* unused import

* remote classes

* Update JFRRemotingFlightRecorder.scala

* stream tests

* javafmt

* doc links

* remove PekkoDependWalker

* build issues

* remove mention of JDK 9

* Update JavaFlowSupport.java

docs/src/test/java/jdocs/stream/operators/source/AsSubscriber.java

@@ -0,0 +1,75 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * license agreements; and to You under the Apache License, version 2.0:
+ *
+ *   https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * This file is part of the Apache Pekko project, which was derived from Akka.
+ */
+
+/*
+ * Copyright (C) 2019-2022 Lightbend Inc. <https://www.lightbend.com>
+ */
+
+package jdocs.stream.operators.source;
+
+// #imports
+import java.util.concurrent.Flow.Subscriber;
+import java.util.concurrent.Flow.Publisher;
+
+import org.apache.pekko.NotUsed;
+import org.apache.pekko.stream.javadsl.Source;
+import org.apache.pekko.stream.javadsl.JavaFlowSupport;
+// #imports
+public interface AsSubscriber {
+  // We are 'faking' the JavaFlowSupport API here so we can include the signature as a snippet in
+  // the API,
+  // because we're not publishing those (jdk9+) classes in our API docs yet.
+  static class JavaFlowSupport {
+    public static final class Source {
+      public
+      // #api
+      static <T> org.apache.pekko.stream.javadsl.Source<T, Subscriber<T>> asSubscriber()
+            // #api
+          {
+        return org.apache.pekko.stream.javadsl.JavaFlowSupport.Source.<T>asSubscriber();
+      }
+    }
+  }
+
+  static class Row {
+    public String getField(String fieldName) {
+      throw new UnsupportedOperationException("Not implemented in sample");
+    }
+  }
+
+  static class DatabaseClient {
+    Publisher<Row> fetchRows() {
+      throw new UnsupportedOperationException("Not implemented in sample");
+    }
+  }
+
+  DatabaseClient databaseClient = null;
+
+  // #example
+  class Example {
+    Source<Row, NotUsed> rowSource =
+        JavaFlowSupport.Source.<Row>asSubscriber()
+            .mapMaterializedValue(
+                subscriber -> {
+                  // For each materialization, fetch the rows from the database:
+                  Publisher<Row> rows = databaseClient.fetchRows();
+                  rows.subscribe(subscriber);
+
+                  return NotUsed.getInstance();
+                });
+
+    public Source<String, NotUsed> names() {
+      // rowSource can be re-used, since it will start a new
+      // query for each materialization, fully supporting backpressure
+      // for each materialized stream:
+      return rowSource.map(row -> row.getField("name"));
+    }
+  }
+  // #example
+}

docs/src/test/java/jdocs/stream/operators/source/FromPublisher.java

@@ -0,0 +1,67 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * license agreements; and to You under the Apache License, version 2.0:
+ *
+ *   https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * This file is part of the Apache Pekko project, which was derived from Akka.
+ */
+
+/*
+ * Copyright (C) 2019-2022 Lightbend Inc. <https://www.lightbend.com>
+ */
+
+package jdocs.stream.operators.source;
+
+// #imports
+import java.util.concurrent.Flow.Publisher;
+
+import org.apache.pekko.NotUsed;
+import org.apache.pekko.stream.javadsl.Source;
+import org.apache.pekko.stream.javadsl.JavaFlowSupport;
+
+// #imports
+
+public interface FromPublisher {
+  // We are 'faking' the JavaFlowSupport API here so we can include the signature as a snippet in
+  // the API,
+  // because we're not publishing those (jdk9+) classes in our API docs yet.
+  static class JavaFlowSupport {
+    public static final class Source {
+      public
+      // #api
+      static <T> org.apache.pekko.stream.javadsl.Source<T, NotUsed> fromPublisher(
+          Publisher<T> publisher)
+            // #api
+          {
+        return org.apache.pekko.stream.javadsl.JavaFlowSupport.Source.<T>fromPublisher(publisher);
+      }
+    }
+  }
+
+  static class Row {
+    public String getField(String fieldName) {
+      throw new UnsupportedOperationException("Not implemented in sample");
+    }
+  }
+
+  static class DatabaseClient {
+    Publisher<Row> fetchRows() {
+      throw new UnsupportedOperationException("Not implemented in sample");
+    }
+  }
+
+  DatabaseClient databaseClient = null;
+
+  // #example
+  class Example {
+    public Source<String, NotUsed> names() {
+      // A new subscriber will subscribe to the supplied publisher for each
+      // materialization, so depending on whether the database client supports
+      // this the Source can be materialized more than once.
+      return JavaFlowSupport.Source.<Row>fromPublisher(databaseClient.fetchRows())
+          .map(row -> row.getField("name"));
+    }
+  }
+  // #example
+}