Package com.launchdarkly.sdk.android.subsystems

Interface PersistentDataStore

  • public interface PersistentDataStore
    Interface for a data store that holds feature flag data and other SDK properties in a simple string format.

    The SDK has a default implementation which uses the Android SharedPreferences API. A custom implementation of this interface could store data somewhere else, or use that API in a different way.

    Each data item is uniquely identified by the combination of a "namespace" and a "key", and has a string value. These are defined as follows:

    • Both the namespace and the key are non-empty strings.
    • Both the namespace and the key contain only alphanumeric characters, hyphens, and underscores.
    • The value can be any non-null string, including an empty string.

    The store implementation does not need to worry about adding a LaunchDarkly-specific prefix to namespaces to distinguish them from storage that is used for other purposes; the SDK will take care of that at a higher level. PersistentDataStore is just a low-level storage mechanism.

    The SDK will also provide its own caching layer on top of the persistent data store; the data store implementation should not provide caching, but simply do every query or update that the SDK tells it to do.

    Error handling is defined as follows: if any data store operation encounters an I/O error, or is otherwise unable to complete its task, it should throw an exception to make the SDK aware of this. The SDK will decide whether to log the exception.

    Since:
    4.0.0

    • Method Summary

      All Methods Instance Methods Abstract Methods 
      Modifier and Type Method Description
      void clear​(java.lang.String storeNamespace, boolean fullyDelete)
      Removes any values that currently exist in the given namespace.
      java.util.Collection<java.lang.String> getAllNamespaces()
      Returns all namespaces that exist in the data store.
      java.util.Collection<java.lang.String> getKeys​(java.lang.String storeNamespace)
      Returns all keys that exist in the namespace.
      java.lang.String getValue​(java.lang.String storeNamespace, java.lang.String key)
      Attempts to retrieve a string value from the store.
      void setValue​(java.lang.String storeNamespace, java.lang.String key, java.lang.String value)
      Attempts to update or remove a string value in the store.
      void setValues​(java.lang.String storeNamespace, java.util.Map<java.lang.String,​java.lang.String> keysAndValues)
      Attempts to update multiple values atomically.

    • Method Detail

      • getValue

        java.lang.String getValue​(java.lang.String storeNamespace,
                          java.lang.String key)
        Attempts to retrieve a string value from the store.
        Parameters:
        storeNamespace - the namespace identifier
        key - the unique key within that namespace
        Returns:
        the value, or null if not found

      • setValue

        void setValue​(java.lang.String storeNamespace,
              java.lang.String key,
              java.lang.String value)
        Attempts to update or remove a string value in the store.
        Parameters:
        storeNamespace - the namespace identifier
        key - the unique key within that namespace
        value - the new value, or null to remove the key

      • setValues

        void setValues​(java.lang.String storeNamespace,
               java.util.Map<java.lang.String,​java.lang.String> keysAndValues)
        Attempts to update multiple values atomically.
        Parameters:
        storeNamespace - the namespace identifier
        keysAndValues - the keys and values to update

      • getKeys

        java.util.Collection<java.lang.String> getKeys​(java.lang.String storeNamespace)
        Returns all keys that exist in the namespace.
        Parameters:
        storeNamespace - the namespace identifier
        Returns:
        the keys

      • getAllNamespaces

        java.util.Collection<java.lang.String> getAllNamespaces()
        Returns all namespaces that exist in the data store.

        This may be an inefficient operation, but the SDK will not call this method on a regular basis. It is used only when migrating data from earlier SDK versions.

        Returns:
        the namespaces

      • clear

        void clear​(java.lang.String storeNamespace,
           boolean fullyDelete)
        Removes any values that currently exist in the given namespace.
        Parameters:
        storeNamespace - the namespace identifier
        fullyDelete - true to purge all data structures related to the namespace, false to simply leave it empty