+per #16541 add missing java samples for persistence query
This commit is contained in:
Konrad Malawski
Konrad Malawski
parent
3b94108e0c
commit
3314de4cb9
10 changed files with 589 additions and 92 deletions
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@ -4,71 +4,373 @@
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package docs.persistence;
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import static akka.pattern.Patterns.ask;
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import akka.actor.*;
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import akka.dispatch.Mapper;
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import akka.event.EventStreamSpec;
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import akka.japi.Function;
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import akka.japi.Procedure;
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import akka.japi.pf.ReceiveBuilder;
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import akka.pattern.BackoffSupervisor;
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import akka.persistence.*;
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import akka.persistence.query.*;
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import akka.persistence.query.javadsl.ReadJournal;
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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 akka.util.Timeout;
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import docs.persistence.query.MyEventsByTagPublisher;
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import docs.persistence.query.PersistenceQueryDocSpec;
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import org.reactivestreams.Subscriber;
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import scala.collection.Seq;
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import scala.collection.immutable.Vector;
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import scala.concurrent.Await;
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import scala.concurrent.Future;
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import scala.concurrent.duration.Duration;
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import scala.concurrent.duration.FiniteDuration;
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import scala.runtime.Boxed;
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import scala.runtime.BoxedUnit;
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import java.io.Serializable;
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import java.util.ArrayList;
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import java.util.Arrays;
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import java.util.List;
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import java.util.concurrent.TimeUnit;
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public class PersistenceQueryDocTest {
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final Timeout timeout = Timeout.durationToTimeout(FiniteDuration.create(3, TimeUnit.SECONDS));
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final ActorSystem system = ActorSystem.create();
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final ActorMaterializer mat = ActorMaterializer.create(system);
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//#my-read-journal
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class MyReadJournal implements ReadJournal {
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private final ExtendedActorSystem system;
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class MyReadJournal implements ReadJournal {
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private final ExtendedActorSystem system;
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public MyReadJournal(ExtendedActorSystem system) {
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this.system = system;
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}
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final FiniteDuration defaultRefreshInterval = FiniteDuration.create(3, TimeUnit.SECONDS);
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final FiniteDuration defaultRefreshInterval = FiniteDuration.create(3, TimeUnit.SECONDS);
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@SuppressWarnings("unchecked")
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public <T, M> Source<T, M> query(Query<T, M> q, Hint... hints) {
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if (q instanceof EventsByTag) {
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final EventsByTag eventsByTag = (EventsByTag) q;
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final String tag = eventsByTag.tag();
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long offset = eventsByTag.offset();
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@SuppressWarnings("unchecked")
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public <T, M> Source<T, M> query(Query<T, M> q, Hint... hints) {
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if (q instanceof EventsByTag) {
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final EventsByTag eventsByTag = (EventsByTag) q;
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final String tag = eventsByTag.tag();
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long offset = eventsByTag.offset();
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final Props props = MyEventsByTagPublisher.props(tag, offset, refreshInterval(hints));
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final Props props = MyEventsByTagPublisher.props(tag, offset, refreshInterval(hints));
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return (Source<T, M>) Source.<EventEnvelope>actorPublisher(props)
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.mapMaterializedValue(noMaterializedValue());
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} else {
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// unsuported
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return Source.<T>failed(
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new UnsupportedOperationException(
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"Query $unsupported not supported by " + getClass().getName()))
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.mapMaterializedValue(noMaterializedValue());
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}
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return (Source<T, M>) Source.<EventEnvelope>actorPublisher(props)
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.mapMaterializedValue(noMaterializedValue());
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} else {
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// unsuported
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return Source.<T>failed(
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new UnsupportedOperationException(
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"Query " + q + " not supported by " + getClass().getName()))
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.mapMaterializedValue(noMaterializedValue());
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}
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}
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private FiniteDuration refreshInterval(Hint[] hints) {
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FiniteDuration ret = defaultRefreshInterval;
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for (Hint hint : hints)
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if (hint instanceof RefreshInterval)
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ret = ((RefreshInterval) hint).interval();
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return ret;
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}
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private FiniteDuration refreshInterval(Hint[] hints) {
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for (Hint hint : hints)
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if (hint instanceof RefreshInterval)
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return ((RefreshInterval) hint).interval();
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private <I, M> akka.japi.function.Function<I, M> noMaterializedValue () {
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return param -> (M) null;
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}
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return defaultRefreshInterval;
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}
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private <I, M> akka.japi.function.Function<I, M> noMaterializedValue() {
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return param -> (M) null;
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}
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}
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//#my-read-journal
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//#my-read-journal
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void demonstrateBasicUsage() {
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final ActorSystem system = ActorSystem.create();
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//#basic-usage
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// obtain read journal by plugin id
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final ReadJournal readJournal =
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PersistenceQuery.get(system)
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.getReadJournalFor("akka.persistence.query.noop-read-journal");
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// issue query to journal
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Source<Object, BoxedUnit> source =
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readJournal.query(EventsByPersistenceId.create("user-1337", 0, Long.MAX_VALUE));
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// materialize stream, consuming events
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ActorMaterializer mat = ActorMaterializer.create(system);
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source.runForeach(event -> System.out.println("Event: " + event), mat);
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//#basic-usage
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}
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void demonstrateAllPersistenceIdsLive() {
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final ReadJournal readJournal =
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PersistenceQuery.get(system)
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.getReadJournalFor("akka.persistence.query.noop-read-journal");
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//#all-persistence-ids-live
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readJournal.query(AllPersistenceIds.getInstance());
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//#all-persistence-ids-live
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}
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void demonstrateNoRefresh() {
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final ActorSystem system = ActorSystem.create();
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final ReadJournal readJournal =
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PersistenceQuery.get(system)
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.getReadJournalFor("akka.persistence.query.noop-read-journal");
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//#all-persistence-ids-snap
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readJournal.query(AllPersistenceIds.getInstance(), NoRefresh.getInstance());
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//#all-persistence-ids-snap
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}
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void demonstrateRefresh() {
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final ActorSystem system = ActorSystem.create();
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final ReadJournal readJournal =
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PersistenceQuery.get(system)
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.getReadJournalFor("akka.persistence.query.noop-read-journal");
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//#events-by-persistent-id-refresh
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final RefreshInterval refresh = RefreshInterval.create(1, TimeUnit.SECONDS);
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readJournal.query(EventsByPersistenceId.create("user-us-1337"), refresh);
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//#events-by-persistent-id-refresh
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}
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void demonstrateEventsByTag() {
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final ActorSystem system = ActorSystem.create();
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final ActorMaterializer mat = ActorMaterializer.create(system);
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final ReadJournal readJournal =
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PersistenceQuery.get(system)
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.getReadJournalFor("akka.persistence.query.noop-read-journal");
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//#events-by-tag
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// assuming journal is able to work with numeric offsets we can:
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final Source<EventEnvelope, BoxedUnit> blueThings =
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readJournal.query(EventsByTag.create("blue"));
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// find top 10 blue things:
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final Future<List<Object>> top10BlueThings =
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(Future<List<Object>>) blueThings
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.map(t -> t.event())
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.take(10) // cancels the query stream after pulling 10 elements
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.<List<Object>>runFold(new ArrayList<>(10), (acc, e) -> {
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acc.add(e);
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return acc;
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}, mat);
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// start another query, from the known offset
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Source<EventEnvelope, BoxedUnit> blue = readJournal.query(EventsByTag.create("blue", 10));
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//#events-by-tag
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}
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//#materialized-query-metadata-classes
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// a plugin can provide:
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//#materialized-query-metadata-classes
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static
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//#materialized-query-metadata-classes
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final class QueryMetadata {
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public final boolean deterministicOrder;
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public final boolean infinite;
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public QueryMetadata(Boolean deterministicOrder, Boolean infinite) {
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this.deterministicOrder = deterministicOrder;
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this.infinite = infinite;
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}
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}
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//#materialized-query-metadata-classes
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static
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//#materialized-query-metadata-classes
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final class AllEvents implements Query<Object, QueryMetadata> {
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private AllEvents() {}
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private static AllEvents INSTANCE = new AllEvents();
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}
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//#materialized-query-metadata-classes
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void demonstrateMaterializedQueryValues() {
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final ActorSystem system = ActorSystem.create();
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final ActorMaterializer mat = ActorMaterializer.create(system);
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final ReadJournal readJournal =
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PersistenceQuery.get(system)
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.getReadJournalFor("akka.persistence.query.noop-read-journal");
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//#materialized-query-metadata
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final Source<Object, QueryMetadata> events = readJournal.query(AllEvents.INSTANCE);
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events.mapMaterializedValue(meta -> {
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System.out.println("The query is: " +
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"ordered deterministically: " + meta.deterministicOrder + " " +
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"infinite: " + meta.infinite);
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return meta;
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});
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//#materialized-query-metadata
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}
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class ReactiveStreamsCompatibleDBDriver {
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Subscriber<List<Object>> batchWriter() {
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return null;
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}
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}
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void demonstrateWritingIntoDifferentStore() {
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final ActorSystem system = ActorSystem.create();
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final ActorMaterializer mat = ActorMaterializer.create(system);
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final ReadJournal readJournal =
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PersistenceQuery.get(system)
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.getReadJournalFor("akka.persistence.query.noop-read-journal");
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//#projection-into-different-store-rs
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final ReactiveStreamsCompatibleDBDriver driver = new ReactiveStreamsCompatibleDBDriver();
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final Subscriber<List<Object>> dbBatchWriter = driver.batchWriter();
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// Using an example (Reactive Streams) Database driver
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readJournal
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.query(EventsByPersistenceId.create("user-1337"))
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.grouped(20) // batch inserts into groups of 20
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.runWith(Sink.create(dbBatchWriter), mat); // write batches to read-side database
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//#projection-into-different-store-rs
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}
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//#projection-into-different-store-simple-classes
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class ExampleStore {
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Future<Void> save(Object any) {
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// ...
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//#projection-into-different-store-simple-classes
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return null;
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//#projection-into-different-store-simple-classes
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}
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}
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//#projection-into-different-store-simple-classes
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void demonstrateWritingIntoDifferentStoreWithMapAsync() {
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final ActorSystem system = ActorSystem.create();
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final ActorMaterializer mat = ActorMaterializer.create(system);
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final ReadJournal readJournal =
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PersistenceQuery.get(system)
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.getReadJournalFor("akka.persistence.query.noop-read-journal");
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//#projection-into-different-store-simple
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final ExampleStore store = new ExampleStore();
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readJournal
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.query(EventsByTag.create("bid"))
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.mapAsync(1, store::save)
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.runWith(Sink.ignore(), mat);
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//#projection-into-different-store-simple
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}
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//#projection-into-different-store
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class MyResumableProjection {
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private final String name;
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public MyResumableProjection(String name) {
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this.name = name;
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}
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public Future<Long> saveProgress(long offset) {
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// ...
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//#projection-into-different-store
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return null;
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//#projection-into-different-store
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}
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public Future<Long> latestOffset() {
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// ...
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//#projection-into-different-store
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return null;
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//#projection-into-different-store
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}
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}
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//#projection-into-different-store
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void demonstrateWritingIntoDifferentStoreWithResumableProjections() throws Exception {
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final ActorSystem system = ActorSystem.create();
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final ActorMaterializer mat = ActorMaterializer.create(system);
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final ReadJournal readJournal =
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PersistenceQuery.get(system)
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.getReadJournalFor("akka.persistence.query.noop-read-journal");
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//#projection-into-different-store-actor-run
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final Timeout timeout = Timeout.apply(3, TimeUnit.SECONDS);
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final MyResumableProjection bidProjection = new MyResumableProjection("bid");
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final Props writerProps = Props.create(TheOneWhoWritesToQueryJournal.class, "bid");
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final ActorRef writer = system.actorOf(writerProps, "bid-projection-writer");
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long startFromOffset = Await.result(bidProjection.latestOffset(), timeout.duration());
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readJournal
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.query(EventsByTag.create("bid", startFromOffset))
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.<Long>mapAsync(8, envelope -> {
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final Future<Object> f = ask(writer, envelope.event(), timeout);
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return f.<Long>map(new Mapper<Object, Long>() {
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@Override public Long apply(Object in) {
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return envelope.offset();
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}
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}, system.dispatcher());
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})
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.mapAsync(1, offset -> bidProjection.saveProgress(offset))
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.runWith(Sink.ignore(), mat);
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}
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//#projection-into-different-store-actor-run
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class ComplexState {
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boolean readyToSave() {
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return false;
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}
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}
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static class Record {
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static Record of(Object any) {
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return new Record();
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}
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}
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//#projection-into-different-store-actor
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final class TheOneWhoWritesToQueryJournal extends AbstractActor {
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private final ExampleStore store;
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private ComplexState state = new ComplexState();
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public TheOneWhoWritesToQueryJournal() {
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store = new ExampleStore();
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receive(ReceiveBuilder.matchAny(message -> {
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state = updateState(state, message);
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// example saving logic that requires state to become ready:
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if (state.readyToSave())
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store.save(Record.of(state));
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}).build());
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}
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ComplexState updateState(ComplexState state, Object msg) {
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// some complicated aggregation logic here ...
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return state;
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}
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}
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//#projection-into-different-store-actor
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}
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@ -5,6 +5,7 @@
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package docs.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.japi.pf.ReceiveBuilder;
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import akka.persistence.PersistentRepr;
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@ -23,6 +24,7 @@ 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 static java.util.stream.Collectors.toList;
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@ -39,21 +41,28 @@ class MyEventsByTagJavaPublisher extends AbstractActorPublisher<EventEnvelope> {
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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 ArrayList<>();
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private List<EventEnvelope> buf = new LinkedList<>();
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private Cancellable continueTask;
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public MyEventsByTagJavaPublisher(Connection connection, String tag, Long offset, FiniteDuration refreshInterval) {
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public MyEventsByTagJavaPublisher(Connection connection,
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String tag,
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Long offset,
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FiniteDuration 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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this.continueTask = context().system().scheduler().schedule(refreshInterval, refreshInterval, self(), CONTINUE, context().dispatcher(), self());
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final Scheduler scheduler = context().system().scheduler();
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this.continueTask = scheduler
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.schedule(refreshInterval, refreshInterval, self(), CONTINUE,
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context().dispatcher(), self());
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receive(ReceiveBuilder
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.matchEquals(CONTINUE, (in) -> {
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query();
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deliverBuf();
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})
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.matchEquals(CONTINUE, (in) -> {
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query();
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deliverBuf();
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})
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.match(Cancel.class, (in) -> {
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context().stop(self());
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})
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@ -71,33 +80,33 @@ class MyEventsByTagJavaPublisher extends AbstractActorPublisher<EventEnvelope> {
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private void query() {
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if (buf.isEmpty()) {
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try {
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PreparedStatement s = connection.prepareStatement(
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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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final String query = "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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final ResultSet rs = s.executeQuery();
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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())
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res.add(Pair.create(rs.getLong(1), rs.getBytes(2)));
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final List<Pair<Long, byte[]>> res = new ArrayList<>(LIMIT);
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while (rs.next())
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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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if (!res.isEmpty()) {
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currentOffset = res.get(res.size() - 1).first();
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}
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buf = res.stream().map(in -> {
|
||||
final Long id = in.first();
|
||||
final byte[] bytes = in.second();
|
||||
|
||||
final PersistentRepr p = serialization.deserialize(bytes, PersistentRepr.class).get();
|
||||
|
||||
return new EventEnvelope(id, p.persistenceId(), p.sequenceNr(), p.payload());
|
||||
}).collect(toList());
|
||||
}
|
||||
|
||||
buf = res.stream().map(in -> {
|
||||
final Long id = in.first();
|
||||
final byte[] bytes = in.second();
|
||||
|
||||
final PersistentRepr p = serialization.deserialize(bytes, PersistentRepr.class).get();
|
||||
|
||||
return new EventEnvelope(id, p.persistenceId(), p.sequenceNr(), p.payload());
|
||||
}).collect(toList());
|
||||
} catch(Exception e) {
|
||||
onErrorThenStop(e);
|
||||
}
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue