Remove docs for ActorPub/Sub and write persistence query docs as stages (#26844)
* use separate db columns * Use io dispatcher for sample stage
This commit is contained in:
Christopher Batey
Patrik Nordwall
parent
2bbf13f707
commit
c65bf2d276
22 changed files with 272 additions and 2194 deletions
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@ -6,6 +6,7 @@ package jdocs.persistence;
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import static akka.pattern.Patterns.ask;
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import java.sql.Connection;
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import java.time.Duration;
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import java.util.HashSet;
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import java.util.Set;
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@ -21,9 +22,8 @@ import akka.stream.ActorMaterializer;
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import akka.stream.javadsl.Sink;
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import akka.stream.javadsl.Source;
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import docs.persistence.query.MyEventsByTagPublisher;
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import jdocs.persistence.query.MyEventsByTagSource;
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import org.reactivestreams.Subscriber;
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import scala.concurrent.duration.FiniteDuration;
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import java.util.ArrayList;
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import java.util.List;
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@ -92,12 +92,11 @@ public class PersistenceQueryDocTest {
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akka.persistence.query.javadsl.PersistenceIdsQuery,
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akka.persistence.query.javadsl.CurrentPersistenceIdsQuery {
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private final FiniteDuration refreshInterval;
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private final Duration refreshInterval;
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private Connection conn;
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public MyJavadslReadJournal(ExtendedActorSystem system, Config config) {
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refreshInterval =
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FiniteDuration.create(
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config.getDuration("refresh-interval", TimeUnit.MILLISECONDS), TimeUnit.MILLISECONDS);
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refreshInterval = config.getDuration("refresh-interval");
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}
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/**
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@ -115,10 +114,8 @@ public class PersistenceQueryDocTest {
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public Source<EventEnvelope, NotUsed> eventsByTag(String tag, Offset offset) {
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if (offset instanceof Sequence) {
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Sequence sequenceOffset = (Sequence) offset;
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final Props props =
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MyEventsByTagPublisher.props(tag, sequenceOffset.value(), refreshInterval);
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return Source.<EventEnvelope>actorPublisher(props)
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.mapMaterializedValue(m -> NotUsed.getInstance());
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return Source.fromGraph(
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new MyEventsByTagSource(conn, tag, sequenceOffset.value(), refreshInterval));
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} else if (offset == NoOffset.getInstance())
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return eventsByTag(tag, Offset.sequence(0L)); // recursive
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else
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@ -1,135 +0,0 @@
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/*
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* Copyright (C) 2015-2019 Lightbend Inc. <https://www.lightbend.com>
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*/
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package jdocs.persistence.query;
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import akka.actor.Cancellable;
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import akka.actor.Scheduler;
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import akka.japi.Pair;
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import akka.persistence.PersistentRepr;
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import akka.persistence.query.Offset;
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import akka.serialization.Serialization;
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import akka.serialization.SerializationExtension;
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import akka.stream.actor.AbstractActorPublisher;
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import akka.actor.Props;
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import akka.persistence.query.EventEnvelope;
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import akka.stream.actor.ActorPublisherMessage.Cancel;
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import java.sql.Connection;
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import java.sql.PreparedStatement;
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import java.sql.ResultSet;
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import java.util.ArrayList;
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import java.util.LinkedList;
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import java.util.List;
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import java.time.Duration;
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import static java.util.stream.Collectors.toList;
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// #events-by-tag-publisher
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class MyEventsByTagJavaPublisher extends AbstractActorPublisher<EventEnvelope> {
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private final Serialization serialization = SerializationExtension.get(getContext().getSystem());
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private final Connection connection;
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private final String tag;
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private final String CONTINUE = "CONTINUE";
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private final int LIMIT = 1000;
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private long currentOffset;
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private List<EventEnvelope> buf = new LinkedList<>();
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private Cancellable continueTask;
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public MyEventsByTagJavaPublisher(
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Connection connection, String tag, Long offset, Duration refreshInterval) {
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this.connection = connection;
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this.tag = tag;
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this.currentOffset = offset;
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final Scheduler scheduler = getContext().getSystem().scheduler();
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this.continueTask =
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scheduler.schedule(
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refreshInterval,
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refreshInterval,
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getSelf(),
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CONTINUE,
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getContext().getDispatcher(),
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getSelf());
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}
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@Override
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public Receive createReceive() {
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return receiveBuilder()
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.matchEquals(
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CONTINUE,
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(in) -> {
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query();
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deliverBuf();
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})
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.match(
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Cancel.class,
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(in) -> {
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getContext().stop(getSelf());
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})
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.build();
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}
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public static Props props(Connection conn, String tag, Long offset, Duration refreshInterval) {
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return Props.create(
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MyEventsByTagJavaPublisher.class,
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() -> new MyEventsByTagJavaPublisher(conn, tag, offset, refreshInterval));
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}
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@Override
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public void postStop() {
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continueTask.cancel();
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}
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private void query() {
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if (buf.isEmpty()) {
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final String query =
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"SELECT id, persistent_repr "
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+ "FROM journal WHERE tag = ? AND id > ? "
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+ "ORDER BY id LIMIT ?";
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try (PreparedStatement s = connection.prepareStatement(query)) {
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s.setString(1, tag);
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s.setLong(2, currentOffset);
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s.setLong(3, LIMIT);
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try (ResultSet rs = s.executeQuery()) {
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final List<Pair<Long, byte[]>> res = new ArrayList<>(LIMIT);
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while (rs.next()) res.add(Pair.create(rs.getLong(1), rs.getBytes(2)));
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if (!res.isEmpty()) {
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currentOffset = res.get(res.size() - 1).first();
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}
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buf =
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res.stream()
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.map(
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in -> {
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final Long id = in.first();
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final byte[] bytes = in.second();
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final PersistentRepr p =
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serialization.deserialize(bytes, PersistentRepr.class).get();
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return new EventEnvelope(
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Offset.sequence(id), p.persistenceId(), p.sequenceNr(), p.payload());
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})
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.collect(toList());
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}
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} catch (Exception e) {
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onErrorThenStop(e);
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}
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}
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}
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private void deliverBuf() {
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while (totalDemand() > 0 && !buf.isEmpty()) onNext(buf.remove(0));
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}
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}
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// #events-by-tag-publisher
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@ -0,0 +1,136 @@
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/*
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* Copyright (C) 2019 Lightbend Inc. <https://www.lightbend.com>
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*/
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package jdocs.persistence.query;
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import akka.actor.ActorSystem;
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import akka.japi.Pair;
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import akka.persistence.PersistentRepr;
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import akka.persistence.query.EventEnvelope;
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import akka.persistence.query.Offset;
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import akka.serialization.Serialization;
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import akka.serialization.SerializationExtension;
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import akka.stream.*;
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import akka.stream.stage.*;
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import java.sql.Connection;
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import java.sql.PreparedStatement;
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import java.sql.ResultSet;
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import java.time.Duration;
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import java.util.ArrayList;
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import java.util.LinkedList;
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import java.util.List;
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import static java.util.stream.Collectors.toList;
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// #events-by-tag-publisher
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public class MyEventsByTagSource extends GraphStage<SourceShape<EventEnvelope>> {
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public Outlet<EventEnvelope> out = Outlet.create("MyEventByTagSource.out");
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private static final String QUERY =
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"SELECT id, persistence_id, seq_nr, serializer_id, serializer_manifest, payload "
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+ "FROM journal WHERE tag = ? AND id > ? "
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+ "ORDER BY id LIMIT ?";
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enum Continue {
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INSTANCE;
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}
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private static final int LIMIT = 1000;
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private final Connection connection;
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private final String tag;
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private final long initialOffset;
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private final Duration refreshInterval;
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// assumes a shared connection, could also be a factory for creating connections/pool
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public MyEventsByTagSource(
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Connection connection, String tag, long initialOffset, Duration refreshInterval) {
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this.connection = connection;
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this.tag = tag;
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this.initialOffset = initialOffset;
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this.refreshInterval = refreshInterval;
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}
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@Override
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public Attributes initialAttributes() {
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return Attributes.apply(ActorAttributes.IODispatcher());
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}
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@Override
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public SourceShape<EventEnvelope> shape() {
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return SourceShape.of(out);
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}
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@Override
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public GraphStageLogic createLogic(Attributes inheritedAttributes) {
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return new TimerGraphStageLogic(shape()) {
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private ActorSystem system = ((ActorMaterializer) materializer()).system();
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private long currentOffset = initialOffset;
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private List<EventEnvelope> buf = new LinkedList<>();
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private final Serialization serialization = SerializationExtension.get(system);
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@Override
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public void preStart() {
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schedulePeriodically(Continue.INSTANCE, refreshInterval);
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}
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@Override
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public void onTimer(Object timerKey) {
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query();
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deliver();
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}
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private void deliver() {
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if (isAvailable(out) && !buf.isEmpty()) {
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push(out, buf.remove(0));
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}
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}
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private void query() {
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if (buf.isEmpty()) {
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try (PreparedStatement s = connection.prepareStatement(QUERY)) {
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s.setString(1, tag);
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s.setLong(2, currentOffset);
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s.setLong(3, LIMIT);
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try (ResultSet rs = s.executeQuery()) {
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final List<EventEnvelope> res = new ArrayList<>(LIMIT);
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while (rs.next()) {
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Object deserialized =
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serialization
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.deserialize(
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rs.getBytes("payload"),
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rs.getInt("serializer_id"),
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rs.getString("serializer_manifest"))
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.get();
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currentOffset = rs.getLong("id");
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res.add(
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new EventEnvelope(
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Offset.sequence(currentOffset),
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rs.getString("persistence_id"),
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rs.getLong("seq_nr"),
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deserialized));
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}
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buf = res;
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}
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} catch (Exception e) {
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failStage(e);
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}
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}
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}
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{
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setHandler(
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out,
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new AbstractOutHandler() {
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@Override
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public void onPull() {
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query();
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deliver();
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}
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});
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}
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};
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}
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}
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// #events-by-tag-publisher
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