=per #18288 Add docs of leveldb queries

akka-docs/rst/java/code/docs/persistence/query/LeveldbPersistenceQueryDocTest.java

@@ -0,0 +1,95 @@
+/**
+ * Copyright (C) 2009-2015 Typesafe Inc. <http://www.typesafe.com>
+ */
+
+package docs.persistence.query;
+
+import java.util.HashSet;
+import java.util.Set;
+import scala.runtime.BoxedUnit;
+
+import akka.actor.ActorSystem;
+import akka.persistence.journal.WriteEventAdapter;
+import akka.persistence.journal.EventSeq;
+import akka.persistence.journal.leveldb.Tagged;
+import akka.persistence.query.AllPersistenceIds;
+import akka.persistence.query.EventEnvelope;
+import akka.persistence.query.EventsByPersistenceId;
+import akka.persistence.query.EventsByTag;
+import akka.persistence.query.PersistenceQuery;
+import akka.persistence.query.javadsl.ReadJournal;
+import akka.persistence.query.journal.leveldb.LeveldbReadJournal;
+import akka.stream.ActorMaterializer;
+import akka.stream.javadsl.Source;
+
+public class LeveldbPersistenceQueryDocTest {
+
+  final ActorSystem system = ActorSystem.create();
+
+  public void demonstrateReadJournal() {
+    //#get-read-journal
+    final ActorMaterializer mat = ActorMaterializer.create(system);
+    
+    ReadJournal queries =
+      PersistenceQuery.get(system).getReadJournalFor(LeveldbReadJournal.Identifier());
+    //#get-read-journal
+  }
+  
+  public void demonstrateEventsByPersistenceId() {
+    //#EventsByPersistenceId
+    ReadJournal queries =
+        PersistenceQuery.get(system).getReadJournalFor(LeveldbReadJournal.Identifier());
+    
+    Source<EventEnvelope, BoxedUnit> source =
+        queries.query(EventsByPersistenceId.create("some-persistence-id", 0, Long.MAX_VALUE));
+    //#EventsByPersistenceId
+  }
+  
+  public void demonstrateAllPersistenceIds() {
+    //#AllPersistenceIds
+    ReadJournal queries =
+        PersistenceQuery.get(system).getReadJournalFor(LeveldbReadJournal.Identifier());
+    
+    Source<String, BoxedUnit> source =
+        queries.query(AllPersistenceIds.getInstance());
+    //#AllPersistenceIds
+  }
+  
+  public void demonstrateEventsByTag() {
+    //#EventsByTag
+    ReadJournal queries =
+        PersistenceQuery.get(system).getReadJournalFor(LeveldbReadJournal.Identifier());
+    
+    Source<EventEnvelope, BoxedUnit> source =
+        queries.query(EventsByTag.create("green", 0));
+    //#EventsByTag
+  }
+  
+  static 
+  //#tagger
+  public class MyEventAdapter implements WriteEventAdapter {
+
+    @Override
+    public Object toJournal(Object event) {
+      if (event instanceof String) {
+        String s = (String) event;
+        Set<String> tags = new HashSet<String>();
+        if (s.contains("green")) tags.add("green");
+        if (s.contains("black")) tags.add("black");
+        if (s.contains("blue")) tags.add("blue");
+        if (tags.isEmpty())
+          return event;
+        else
+          return new Tagged(event, tags);
+      } else {
+        return event;
+      }
+    }
+    
+    @Override
+    public String manifest(Object event) {
+      return "";
+    }
+  }
+  //#tagger
+}