
io.nats.client.impl.NatsFeatureBase Maven / Gradle / Ivy
// Copyright 2022 The NATS Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at:
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package io.nats.client.impl;
import io.nats.client.*;
import io.nats.client.api.AckPolicy;
import io.nats.client.api.ConsumerConfiguration;
import io.nats.client.api.DeliverPolicy;
import io.nats.client.api.MessageInfo;
import java.io.IOException;
import java.time.Duration;
import java.util.Collections;
import java.util.List;
import static io.nats.client.support.NatsJetStreamConstants.JS_NO_MESSAGE_FOUND_ERR;
public class NatsFeatureBase {
protected final NatsJetStream js;
protected final JetStreamManagement jsm;
protected String streamName;
NatsFeatureBase(NatsConnection connection, FeatureOptions fo) throws IOException {
if (fo == null) {
js = new NatsJetStream(connection, null);
jsm = new NatsJetStreamManagement(connection, null);
}
else {
js = new NatsJetStream(connection, fo.getJetStreamOptions());
jsm = new NatsJetStreamManagement(connection, fo.getJetStreamOptions());
}
}
String getStreamName() {
return streamName;
}
protected MessageInfo _getLast(String subject) throws IOException, JetStreamApiException {
try {
return jsm.getLastMessage(streamName, subject);
}
catch (JetStreamApiException jsae) {
if (jsae.getApiErrorCode() == JS_NO_MESSAGE_FOUND_ERR) {
return null;
}
throw jsae;
}
}
protected MessageInfo _getBySeq(long seq) throws IOException, JetStreamApiException {
try {
return jsm.getMessage(streamName, seq);
}
catch (JetStreamApiException jsae) {
if (jsae.getApiErrorCode() == JS_NO_MESSAGE_FOUND_ERR) {
return null;
}
throw jsae;
}
}
protected void visitSubject(String subject, DeliverPolicy deliverPolicy, boolean headersOnly, boolean ordered, MessageHandler handler) throws IOException, JetStreamApiException, InterruptedException {
visitSubject(Collections.singletonList(subject), deliverPolicy, headersOnly, ordered, handler);
}
protected void visitSubject(List subjects, DeliverPolicy deliverPolicy, boolean headersOnly, boolean ordered, MessageHandler handler) throws IOException, JetStreamApiException, InterruptedException {
ConsumerConfiguration.Builder ccb = ConsumerConfiguration.builder()
.ackPolicy(AckPolicy.None)
.deliverPolicy(deliverPolicy)
.headersOnly(headersOnly)
.filterSubjects(subjects);
PushSubscribeOptions pso = PushSubscribeOptions.builder()
.stream(streamName)
.ordered(ordered)
.configuration(ccb.build())
.build();
Duration timeout = js.jso.getRequestTimeout();
JetStreamSubscription sub = js.subscribe(null, pso);
try {
boolean lastWasNull = false;
long pending = sub.getConsumerInfo().getCalculatedPending();
while (pending > 0) { // no need to loop if nothing pending
Message m = sub.nextMessage(timeout);
if (m == null) {
if (lastWasNull) {
return; // two timeouts in a row is enough
}
lastWasNull = true;
}
else {
handler.onMessage(m);
if (--pending == 0) {
return;
}
lastWasNull = false;
}
}
}
finally {
sub.unsubscribe();
}
}
}
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