com.launchdarkly.client.integrations

Class PersistentDataStoreBuilder

java.lang.Object

com.launchdarkly.client.integrations.PersistentDataStoreBuilder

All Implemented Interfaces:

FeatureStoreFactory, DiagnosticDescription

public abstract class PersistentDataStoreBuilder
extends java.lang.Object
implements FeatureStoreFactory, DiagnosticDescription

A configurable factory for a persistent data store.

Several database integrations exist for the LaunchDarkly SDK, each with its own behavior and options specific to that database; this is described via some implementation of PersistentDataStoreFactory. There is also universal behavior that the SDK provides for all persistent data stores, such as caching; the PersistentDataStoreBuilder adds this.

After configuring this object, pass it to LDConfig.Builder.dataStore(FeatureStoreFactory) to use it in the SDK configuration. For example, using the Redis integration:

     LDConfig config = new LDConfig.Builder()
         .dataStore(
             Components.persistentDataStore(
                 Redis.dataStore().url("redis://my-redis-host")
             ).cacheSeconds(15)
         )
         .build();
 

In this example, .url() is an option specifically for the Redis integration, whereas ttlSeconds() is an option that can be used for any persistent data store.

Note that this class is abstract; the actual implementation is created by calling Components.persistentDataStore(PersistentDataStoreFactory).

Since:

4.12.0

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	PersistentDataStoreBuilder.StaleValuesPolicy Possible values for staleValuesPolicy(StaleValuesPolicy).

Field Summary

Fields

Modifier and Type	Field and Description
protected CacheMonitor	cacheMonitor
protected FeatureStoreCacheConfig	caching
static int	DEFAULT_CACHE_TTL_SECONDS The default value for the cache TTL.
protected PersistentDataStoreFactory	persistentDataStoreFactory

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	PersistentDataStoreBuilder(PersistentDataStoreFactory persistentDataStoreFactory) Creates a new builder.

Method Summary

Modifier and Type	Method and Description
PersistentDataStoreBuilder	cacheForever() Specifies that the in-memory cache should never expire.
PersistentDataStoreBuilder	cacheMillis(long millis) Shortcut for calling cacheTime(long, TimeUnit) with TimeUnit.MILLISECONDS.
PersistentDataStoreBuilder	cacheMonitor(CacheMonitor cacheMonitor) Provides a conduit for an application to monitor the effectiveness of the in-memory cache.
PersistentDataStoreBuilder	cacheSeconds(long seconds) Shortcut for calling cacheTime(long, TimeUnit) with TimeUnit.SECONDS.
PersistentDataStoreBuilder	cacheTime(long cacheTime, java.util.concurrent.TimeUnit cacheTimeUnit) Specifies the cache TTL.
PersistentDataStoreBuilder	noCaching() Specifies that the SDK should not use an in-memory cache for the persistent data store.
PersistentDataStoreBuilder	staleValuesPolicy(PersistentDataStoreBuilder.StaleValuesPolicy staleValuesPolicy) Specifies how the cache (if any) should deal with old values when the cache TTL expires.

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.launchdarkly.client.FeatureStoreFactory

createFeatureStore

Methods inherited from interface com.launchdarkly.client.interfaces.DiagnosticDescription

describeConfiguration

Field Detail

DEFAULT_CACHE_TTL_SECONDS

public static final int DEFAULT_CACHE_TTL_SECONDS

The default value for the cache TTL.

See Also:

Constant Field Values

persistentDataStoreFactory

protected final PersistentDataStoreFactory persistentDataStoreFactory

caching

protected FeatureStoreCacheConfig caching

cacheMonitor

protected CacheMonitor cacheMonitor

Constructor Detail

PersistentDataStoreBuilder

protected PersistentDataStoreBuilder(PersistentDataStoreFactory persistentDataStoreFactory)

Creates a new builder.

Parameters:

persistentDataStoreFactory - the factory implementation for the specific data store type

Method Detail

noCaching

public PersistentDataStoreBuilder noCaching()

Specifies that the SDK should not use an in-memory cache for the persistent data store. This means that every feature flag evaluation will trigger a data store query.

Returns:

the builder

cacheTime

public PersistentDataStoreBuilder cacheTime(long cacheTime,
                                            java.util.concurrent.TimeUnit cacheTimeUnit)

Specifies the cache TTL. Items will be evicted or refreshed (depending on the StaleValuesPolicy) after this amount of time from the time when they were originally cached.

If the value is zero, caching is disabled (equivalent to noCaching()).

If the value is negative, data is cached forever (equivalent to cacheForever()).

Parameters:

cacheTime - the cache TTL in whatever units you wish

cacheTimeUnit - the time unit

Returns:

the builder

cacheMillis

public PersistentDataStoreBuilder cacheMillis(long millis)

Shortcut for calling cacheTime(long, TimeUnit) with TimeUnit.MILLISECONDS.

Parameters:

millis - the cache TTL in milliseconds

Returns:

the builder

cacheSeconds

public PersistentDataStoreBuilder cacheSeconds(long seconds)

Shortcut for calling cacheTime(long, TimeUnit) with TimeUnit.SECONDS.

Parameters:

seconds - the cache TTL in seconds

Returns:

the builder

cacheForever

public PersistentDataStoreBuilder cacheForever()

Specifies that the in-memory cache should never expire. In this mode, data will be written to both the underlying persistent store and the cache, but will only ever be read from the persistent store if the SDK is restarted.

Use this mode with caution: it means that in a scenario where multiple processes are sharing the database, and the current process loses connectivity to LaunchDarkly while other processes are still receiving updates and writing them to the database, the current process will have stale data.

Returns:

the builder

staleValuesPolicy

public PersistentDataStoreBuilder staleValuesPolicy(PersistentDataStoreBuilder.StaleValuesPolicy staleValuesPolicy)

Specifies how the cache (if any) should deal with old values when the cache TTL expires. The default is PersistentDataStoreBuilder.StaleValuesPolicy.EVICT. This property has no effect if caching is disabled.

Parameters:

staleValuesPolicy - a PersistentDataStoreBuilder.StaleValuesPolicy constant

Returns:

the builder

cacheMonitor

public PersistentDataStoreBuilder cacheMonitor(CacheMonitor cacheMonitor)

Provides a conduit for an application to monitor the effectiveness of the in-memory cache.

Create an instance of CacheMonitor; retain a reference to it, and also pass it to this method when you are configuring the persistent data store. The store will use CacheMonitor.setSource(java.util.concurrent.Callable) to make the caching statistics available through that CacheMonitor instance.

Note that turning on cache monitoring may slightly decrease performance, due to the need to record statistics for each cache operation.

Example usage:

     CacheMonitor cacheMonitor = new CacheMonitor();
     LDConfig config = new LDConfig.Builder()
         .dataStore(Components.persistentDataStore(Redis.dataStore()).cacheMonitor(cacheMonitor))
         .build();
     // later...
     CacheMonitor.CacheStats stats = cacheMonitor.getCacheStats();
 

Parameters:

cacheMonitor - an instance of CacheMonitor

Returns:

the builder