io.aeron.samples.archive

Class RecordingDescriptorCollector

java.lang.Object

io.aeron.samples.archive.RecordingDescriptorCollector

public class RecordingDescriptorCollector
extends Object

Sample utility class for collecting RecordingDescriptors. This aims to be memory and allocation efficient by pooling instances of the descriptors. The user must decide on the size of the pool at allocation time. If the pool size is set to 0 then no pooling will occur and all instances will be recreated. This may be desirable if the user wanted to hold onto descriptors over multiple calls to AeronArchive's list recording methods. If the user wants to have pooling, but needs to retain some instances, then they can call the retain method on the RecordingDescriptor.

Typical usage may be something like:

 final int pageSize;
 final RecordingDescriptorCollector collector = new RecordingDescriptorCollector(pageSize);
 int count;
 long fromRecordingId = 0;
 while (0 != (count = aeronArchive.listRecordings(fromRecordingId, pageSize, collector.reset())
 {
     for (final RecordingDescriptor descriptor : collector.descriptors())
     {
         if (\/* some interesting condition *\/)
         {
             // Want to hang onto this one...
             descriptor.retain();
         }
     }

     fromRecordingId += count;
 }
 

See Also:

AeronArchive.listRecordings(long, int, RecordingDescriptorConsumer), AeronArchive.listRecording(long, RecordingDescriptorConsumer), AeronArchive.listRecordingsForUri(long, int, String, int, RecordingDescriptorConsumer), RecordingDescriptor.retain()

Constructor Summary

Constructors

Constructor and Description
RecordingDescriptorCollector(int poolSize) Construct the collector with the specified pool size.

Method Summary

Modifier and Type	Method and Description
List<RecordingDescriptor>	descriptors() The results from the list of recording descriptors.
int	poolSize() The configured pool size.
RecordingDescriptorConsumer	reset() Reset the result list for the collector.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

RecordingDescriptorCollector

public RecordingDescriptorCollector(int poolSize)

Construct the collector with the specified pool size. If the list recordings call returns more descriptors than the size of the pool then this class will still work, but will allocate new instances and leave them to be garbage collected on reset(). Therefore, setting poolSize to 0 will effectively disable pooling.

Parameters:

poolSize - size of the descriptor pool

Method Detail

reset

public RecordingDescriptorConsumer reset()

Reset the result list for the collector. Removes all the instances from the collection and returns them the pool if the size of the pool and the retained status of the descriptor allows.

Returns:

the consumer to be passed into the AeronArchives's list recording methods.

descriptors

public List<RecordingDescriptor> descriptors()

The results from the list of recording descriptors. This collection is emptied everytime reset() is called and refilled on subsequent queries.

Returns:

the result list of descriptors.

poolSize

public int poolSize()

The configured pool size.

Returns:

number of descriptors that will be pooled.