/**
*
* Copyright
* 2009-2015 Jayway Products AB
* 2016-2017 Föreningen Sambruk
*
* Licensed under AGPL, Version 3.0 (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.gnu.org/licenses/agpl.txt
*
* 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 se.streamsource.streamflow.infrastructure.event.application.source.helper;
import org.qi4j.api.configuration.Configuration;
import org.qi4j.api.io.Output;
import org.qi4j.api.io.Receiver;
import org.qi4j.api.io.Sender;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import se.streamsource.streamflow.infrastructure.event.application.TransactionApplicationEvents;
import se.streamsource.streamflow.infrastructure.event.application.source.ApplicationEventSource;
import se.streamsource.streamflow.infrastructure.event.application.source.ApplicationEventStream;
import se.streamsource.streamflow.infrastructure.event.domain.source.helper.TransactionTrackerConfiguration;
/**
* Helper that enables a service to easily track transactions. Upon startup
* the tracker will get all the transactions from the store since the last
* check, and delegate them to the given Output. It will also register itself
* with the store so that it can get continuous updates.
* <p/>
* Then, as transactions come in from the store, they will be processed in real-time.
* If a transaction is successfully handled the configuration of the service, which must
* extend TransactionTrackerConfiguration, will update the marker for the last successfully handled transaction.
*/
public class ApplicationTransactionTracker<ReceiverThrowableType extends Throwable>
{
private Configuration<? extends TransactionTrackerConfiguration> configuration;
private Output<TransactionApplicationEvents, ReceiverThrowableType> output;
private ApplicationEventStream stream;
private ApplicationEventSource source;
private boolean started = false;
private boolean upToSpeed = false;
private Logger logger;
private Output<TransactionApplicationEvents, ReceiverThrowableType> trackerOutput;
public ApplicationTransactionTracker(ApplicationEventStream stream, ApplicationEventSource source,
Configuration<? extends TransactionTrackerConfiguration> configuration,
Output<TransactionApplicationEvents, ReceiverThrowableType> output)
{
this.stream = stream;
this.configuration = configuration;
this.source = source;
this.output = output;
logger = LoggerFactory.getLogger(output.getClass());
}
public void start()
{
if (!started)
{
started = true;
// Get events since last check
upToSpeed = true; // Pretend that we are up to speed from now on
trackerOutput = output();
try
{
source.transactionsAfter(configuration.configuration().lastEventDate().get(), Long.MAX_VALUE).transferTo(trackerOutput);
} catch (Throwable receiverThrowableType)
{
upToSpeed = false;
}
stream.registerListener(trackerOutput);
}
}
public void stop()
{
if (started)
{
started = false;
stream.unregisterListener(trackerOutput);
upToSpeed = false;
}
}
private Output<TransactionApplicationEvents, ReceiverThrowableType> output()
{
return new Output<TransactionApplicationEvents, ReceiverThrowableType>()
{
public <SenderThrowableType extends Throwable> void receiveFrom(final Sender<? extends TransactionApplicationEvents, SenderThrowableType> sender) throws ReceiverThrowableType, SenderThrowableType
{
if (!upToSpeed)
{
// The tracker has not handled successfully all transactions before,
// so it needs to get the backlog first
upToSpeed = true; // Pretend that we are up to speed from now on
// Get all transactions from last timestamp, including the one in this call
try
{
source.transactionsAfter(configuration.configuration().lastEventDate().get(), Long.MAX_VALUE).transferTo(trackerOutput);
} catch (Throwable e)
{
upToSpeed = false;
throw (SenderThrowableType) e;
}
}
try
{
output.receiveFrom(new Sender<TransactionApplicationEvents, SenderThrowableType>()
{
public <ReceiverThrowableType extends Throwable> void sendTo(final Receiver<? super TransactionApplicationEvents, ReceiverThrowableType> receiver) throws ReceiverThrowableType, SenderThrowableType
{
sender.sendTo(new Receiver<TransactionApplicationEvents, ReceiverThrowableType>()
{
public void receive(TransactionApplicationEvents item) throws ReceiverThrowableType
{
receiver.receive(item);
// Events in this transactionDomain were handled successfully so store new marker
configuration.configuration().lastEventDate().set(item.timestamp().get());
configuration.save();
}
});
}
});
} catch (Throwable receiverThrowableType)
{
upToSpeed = false;
throw (ReceiverThrowableType) receiverThrowableType;
}
}
};
}
}