PersistenceStrategy

```
public interface PersistenceStrategy

                    
```
The main strategy used to persist data between the moment it's tracked and created, and the moment it's uploaded to the intake.

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description
`public interface`	`PersistenceStrategy.Factory`	A factory used to create an instance of a PersistenceStrategy. Each instance of a persistence strategy should have independent storage. Data written to one instance must not be readable from another one.
`public final class`	`PersistenceStrategy.Batch`	Describes the content of event batch.

Method Summary

Modifier and Type	Method	Description
`abstract ByteArray`	`currentMetadata()`
`abstract Boolean`	`write(RawBatchEvent event, ByteArray batchMetadata, EventType eventType)`	Writes the content of the event to the current available batch.
`abstract PersistenceStrategy.Batch`	`lockAndReadNext()`	Reads the next batch of data and lock it so that it can't be read or written to by anyone.
`abstract Unit`	`unlockAndKeep(String batchId)`	Marks the batch as unlocked and to be kept to be read again later.
`abstract Unit`	`unlockAndDelete(String batchId)`	Marks the batch as unlocked and to be deleted.
`abstract Unit`	`dropAll()`	Drop all data.
`abstract Unit`	`migrateData(PersistenceStrategy targetStrategy)`	Migrate the data to a different PersistenceStrategy.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Method Detail
  - currentMetadata
```
@WorkerThread() abstract ByteArray currentMetadata()
```
  - write
```
@WorkerThread() abstract Boolean write(RawBatchEvent event, ByteArray batchMetadata, EventType eventType)
```
    Writes the content of the event to the current available batch.
    
    Parameters:
    
    event - the event to write (content + metadata)
    
    batchMetadata - the optional updated batch metadata
    
    eventType - additional information about the event that can impact the way it is stored.
  - lockAndReadNext
```
@WorkerThread() abstract PersistenceStrategy.Batch lockAndReadNext()
```
    Reads the next batch of data and lock it so that it can't be read or written to by anyone.
  - unlockAndKeep
```
@WorkerThread() abstract Unit unlockAndKeep(String batchId)
```
    Marks the batch as unlocked and to be kept to be read again later.
  - unlockAndDelete
```
@WorkerThread() abstract Unit unlockAndDelete(String batchId)
```
    Marks the batch as unlocked and to be deleted. The corresponding batch should not be returned in any call to lockAndReadNext.
  - dropAll
```
@WorkerThread() abstract Unit dropAll()
```
    Drop all data.
  - migrateData
```
 abstract Unit migrateData(PersistenceStrategy targetStrategy)
```
    Migrate the data to a different PersistenceStrategy. All readable and ongoing batches must be transferred to the given strategy.