+per #16541 allow using javadsl implemented journals as-if scaladsl

akka-docs/rst/java/code/docs/persistence/PersistenceQueryDocTest.java

@@ -69,7 +69,6 @@ public class PersistenceQueryDocTest {
         private <I, M> akka.japi.function.Function<I, M> noMaterializedValue () {
           return param -> (M) null;
         }
-
   }
     //#my-read-journal
 }

akka-persistence-query/src/main/java/akka/persistence/query/javadsl/ReadJournal.java

@@ -2,45 +2,44 @@
  * Copyright (C) 2009-2015 Typesafe Inc. <http://www.typesafe.com>
  */
 
-package akka.persistence.query.javadsl
+package akka.persistence.query.javadsl;
 
-import akka.persistence.query.{ Query, Hint }
-import akka.stream.javadsl.Source
-
-import scala.annotation.varargs
+import akka.persistence.query.Query;
+import akka.persistence.query.Hint;
+import akka.stream.javadsl.Source;
+import scala.annotation.varargs;
 
 /**
  * Java API
- *
+ * <p>
  * API for reading persistent events and information derived
  * from stored persistent events.
- *
+ * <p>
  * The purpose of the API is not to enforce compatibility between different
  * journal implementations, because the technical capabilities may be very different.
  * The interface is very open so that different journals may implement specific queries.
- *
+ * <p>
  * Usage:
- * {{{
+ * <pre><code>
  * final ReadJournal journal =
  *   PersistenceQuery.get(system).getReadJournalFor(queryPluginConfigPath);
  *
  * final Source&lt;EventEnvelope, ?&gt; events =
  *   journal.query(new EventsByTag("mytag", 0L));
- * }}}
+ * </pre></code>
  */
 
-trait ReadJournal {
+public interface ReadJournal {
 
   /**
    * Java API
-   *
+   * <p>
    * A query that returns a `Source` with output type `T` and materialized value `M`.
-   *
+   * <p>
    * The `hints` are optional parameters that defines how to execute the
    * query, typically specific to the journal implementation.
    *
    */
-  @varargs def query[T, M](q: Query[T, M], hints: Hint*): Source[T, M]
-
+  <T, M> Source<T, M> query(Query<T, M> q, Hint... hints);
 
 }

akka-persistence-query/src/main/java/akka/persistence/query/javadsl/ReadJournalAdapter.java

@@ -0,0 +1,31 @@
+/*
+ * Copyright (C) 2009-2015 Typesafe Inc. <http://www.typesafe.com>
+ */
+
+package akka.persistence.query.javadsl;
+
+import akka.japi.Util;
+import akka.persistence.query.Hint;
+import akka.persistence.query.Query;
+import akka.stream.javadsl.Source;
+
+/**
+ * INTERNAL API
+ *
+ * Adapter from ScalaDSL {@link akka.persistence.query.scaladsl.ReadJournal}
+ * to JavaDSL {@link ReadJournal}.
+ */
+public final class ReadJournalAdapter implements ReadJournal {
+
+  private final akka.persistence.query.scaladsl.ReadJournal backing;
+
+  public ReadJournalAdapter(akka.persistence.query.scaladsl.ReadJournal backing) {
+    this.backing = backing;
+  }
+
+  @Override
+  public <T, M> Source<T, M> query(Query<T, M> q, Hint... hints) {
+    return backing.query(q, Util.immutableSeq(hints)).asJava();
+  }
+
+}

akka-persistence-query/src/main/scala/akka/persistence/query/PersistenceQuery.scala

@@ -7,9 +7,8 @@ import java.util.concurrent.atomic.AtomicReference
 
 import akka.actor._
 import akka.event.Logging
-import akka.stream.javadsl.Source
 
-import scala.annotation.{varargs, tailrec}
+import scala.annotation.tailrec
 import scala.util.Failure
 
 /**
@@ -63,12 +62,7 @@ class PersistenceQuery(system: ExtendedActorSystem) extends Extension {
    * Returns the [[akka.persistence.query.javadsl.ReadJournal]] specified by the given read journal configuration entry.
    */
   final def getReadJournalFor(readJournalPluginId: String): javadsl.ReadJournal =
-    new javadsl.ReadJournal {
-      val backing = readJournalFor(readJournalPluginId)
-      @varargs def query[T, M](q: Query[T, M], hints: Hint*): Source[T, M] =
-        backing.query(q, hints: _*).asJava
-    }
-
+    new javadsl.ReadJournalAdapter(readJournalFor(readJournalPluginId))
 
   private def createPlugin(configPath: String): scaladsl.ReadJournal = {
     require(!isEmpty(configPath) && system.settings.config.hasPath(configPath),
@@ -79,14 +73,24 @@ class PersistenceQuery(system: ExtendedActorSystem) extends Extension {
     log.debug(s"Create plugin: ${pluginActorName} ${pluginClassName}")
     val pluginClass = system.dynamicAccess.getClassFor[AnyRef](pluginClassName).get
 
-    val plugin = system.dynamicAccess.createInstanceFor[scaladsl.ReadJournal](pluginClass, (classOf[ExtendedActorSystem], system) :: Nil)
+    // TODO remove duplication
+    val scalaPlugin =
+      if (classOf[scaladsl.ReadJournal].isAssignableFrom(pluginClass))
+        system.dynamicAccess.createInstanceFor[scaladsl.ReadJournal](pluginClass, (classOf[ExtendedActorSystem], system) :: Nil)
           .orElse(system.dynamicAccess.createInstanceFor[scaladsl.ReadJournal](pluginClass, Nil))
           .recoverWith {
             case ex: Exception ⇒ Failure.apply(new IllegalArgumentException(s"Unable to create read journal plugin instance for path [$configPath], class [$pluginClassName]!", ex))
           }
+      else if (classOf[javadsl.ReadJournal].isAssignableFrom(pluginClass))
+        system.dynamicAccess.createInstanceFor[javadsl.ReadJournal](pluginClass, (classOf[ExtendedActorSystem], system) :: Nil)
+          .orElse(system.dynamicAccess.createInstanceFor[javadsl.ReadJournal](pluginClass, Nil))
+          .map(jj ⇒ new scaladsl.ReadJournalAdapter(jj))
+          .recoverWith {
+            case ex: Exception ⇒ Failure.apply(new IllegalArgumentException(s"Unable to create read journal plugin instance for path [$configPath], class [$pluginClassName]!", ex))
+          }
+      else throw new IllegalArgumentException(s"Configured class ${pluginClass} does not extend")
 
-    // TODO possibly apply event adapters here
-    plugin.get
+    scalaPlugin.get
   }
 
   /** Check for default or missing identity. */

akka-persistence-query/src/main/scala/akka/persistence/query/scaladsl/ReadJournal.scala

@@ -36,3 +36,9 @@ abstract class ReadJournal {
   def query[T, M](q: Query[T, M], hints: Hint*): Source[T, M]
 
 }
+
+/** INTERNAL API */
+private[akka] final class ReadJournalAdapter(backing: akka.persistence.query.javadsl.ReadJournal) extends ReadJournal {
+  override def query[T, M](q: Query[T, M], hints: Hint*): Source[T, M] =
+    backing.query(q, hints: _*).asScala
+}

akka-persistence-query/src/test/java/akka/persistence/query/MockJavaReadJournal.java

@@ -0,0 +1,38 @@
+/*
+ * Copyright (C) 2009-2015 Typesafe Inc. <http://www.typesafe.com>
+ */
+
+package akka.persistence.query;
+
+import akka.persistence.query.javadsl.ReadJournal;
+import akka.stream.javadsl.Source;
+import com.typesafe.config.Config;
+import com.typesafe.config.ConfigFactory;
+
+import java.util.Iterator;
+
+/**
+ * Use for tests only!
+ * Emits infinite stream of strings (representing queried for events).
+ */
+class MockJavaReadJournal implements ReadJournal {
+  public static final String Identifier = "akka.persistence.query.journal.mock-java";
+
+  public static final Config config = ConfigFactory.parseString(
+    Identifier + " { \n" +
+      "   class = \"" + MockJavaReadJournal.class.getCanonicalName() + "\" \n" +
+      " }\n\n");
+
+  @Override
+  @SuppressWarnings("unchecked")
+  public <T, M> Source<T, M> query(Query<T, M> q, Hint... hints) {
+    return (Source<T, M>) Source.fromIterator(() -> new Iterator<String>() {
+      private int i = 0;
+      @Override public boolean hasNext() { return true; }
+
+      @Override public String next() {
+        return "" + (i++);
+      }
+    });
+  }
+}

akka-persistence-query/src/test/scala/akka/persistence/query/PersistenceQuerySpec.scala

@@ -10,12 +10,11 @@ import akka.actor.ActorSystem
 import akka.persistence.journal.{ EventAdapter, EventSeq }
 import com.typesafe.config.ConfigFactory
 import org.scalatest.{ BeforeAndAfterAll, Matchers, WordSpecLike }
-import org.scalautils.ConversionCheckedTripleEquals
 
 import scala.concurrent.Await
 import scala.concurrent.duration._
 
-class PersistenceQuerySpec extends WordSpecLike with Matchers with BeforeAndAfterAll with ConversionCheckedTripleEquals {
+class PersistenceQuerySpec extends WordSpecLike with Matchers with BeforeAndAfterAll {
 
   val anything: Query[String, _] = null
 
@@ -42,12 +41,24 @@ class PersistenceQuerySpec extends WordSpecLike with Matchers with BeforeAndAfte
         }.getMessage should include("missing persistence read journal")
       }
     }
+
+    "expose scaladsl implemented journal as javadsl.ReadJournal" in {
+      withActorSystem() { system ⇒
+        val j: javadsl.ReadJournal = PersistenceQuery.get(system).getReadJournalFor(MockReadJournal.Identifier)
+      }
+    }
+    "expose javadsl implemented journal as scaladsl.ReadJournal" in {
+      withActorSystem() { system ⇒
+        val j: scaladsl.ReadJournal = PersistenceQuery.get(system).readJournalFor(MockJavaReadJournal.Identifier)
+      }
+    }
   }
 
   private val systemCounter = new AtomicInteger()
   private def withActorSystem(conf: String = "")(block: ActorSystem ⇒ Unit): Unit = {
     val config =
       MockReadJournal.config
+        .withFallback(MockJavaReadJournal.config)
         .withFallback(ConfigFactory.parseString(conf))
         .withFallback(ConfigFactory.parseString(eventAdaptersConfig))
         .withFallback(ConfigFactory.load())