Package com.launchdarkly.sdk.server

Class LDClient

  • All Implemented Interfaces:
    LDClientInterface, java.io.Closeable, java.lang.AutoCloseable
    public final class LDClient
extends java.lang.Object
implements LDClientInterface
    A client for the LaunchDarkly API. Client instances are thread-safe. Applications should instantiate a single LDClient for the lifetime of their application.

    • Constructor Summary

      Constructors 
      Constructor Description
      LDClient​(java.lang.String sdkKey)
      Creates a new client instance that connects to LaunchDarkly with the default configuration.
      LDClient​(java.lang.String sdkKey, LDConfig config)
      Creates a new client to connect to LaunchDarkly with a custom configuration.

    • Constructor Detail

      • LDClient

        public LDClient​(java.lang.String sdkKey)
        Creates a new client instance that connects to LaunchDarkly with the default configuration.

        If you need to specify any custom SDK options, use LDClient(String, LDConfig) instead.

        Applications should instantiate a single instance for the lifetime of the application. In unusual cases where an application needs to evaluate feature flags from different LaunchDarkly projects or environments, you may create multiple clients, but they should still be retained for the lifetime of the application rather than created per request or per thread.

        The client will begin attempting to connect to LaunchDarkly as soon as you call the constructor. The constructor will return when it successfully connects, or when the default timeout of 5 seconds expires, whichever comes first. If it has not succeeded in connecting when the timeout elapses, you will receive the client in an uninitialized state where feature flags will return default values; it will still continue trying to connect in the background. You can detect whether initialization has succeeded by calling isInitialized(). If you prefer to customize this behavior, use LDClient(String, LDConfig) instead.

        For rules regarding the throwing of unchecked exceptions for error conditions, see LDClient(String, LDConfig).

        Parameters:
        sdkKey - the SDK key for your LaunchDarkly environment
        Throws:
        java.lang.IllegalArgumentException - if a parameter contained a grossly malformed value; for security reasons, in case of an illegal SDK key, the exception message does not include the key
        java.lang.NullPointerException - if a non-nullable parameter was null
        See Also:
        LDClient(String, LDConfig)

      • LDClient

        public LDClient​(java.lang.String sdkKey,
                LDConfig config)
        Creates a new client to connect to LaunchDarkly with a custom configuration.

        This constructor can be used to configure advanced SDK features; see LDConfig.Builder.

        Applications should instantiate a single instance for the lifetime of the application. In unusual cases where an application needs to evaluate feature flags from different LaunchDarkly projects or environments, you may create multiple clients, but they should still be retained for the lifetime of the application rather than created per request or per thread.

        Unless it is configured to be offline with LDConfig.Builder.offline(boolean) or Components.externalUpdatesOnly(), the client will begin attempting to connect to LaunchDarkly as soon as you call the constructor. The constructor will return when it successfully connects, or when the timeout set by LDConfig.Builder.startWait(java.time.Duration) (default: 5 seconds) expires, whichever comes first. If it has not succeeded in connecting when the timeout elapses, you will receive the client in an uninitialized state where feature flags will return default values; it will still continue trying to connect in the background. You can detect whether initialization has succeeded by calling isInitialized().

        If you prefer to have the constructor return immediately, and then wait for initialization to finish at some other point, you can use getDataSourceStatusProvider() as follows: 

        
     LDConfig config = new LDConfig.Builder()
         .startWait(Duration.ZERO)
         .build();
     LDClient client = new LDClient(sdkKey, config);
     
     // later, when you want to wait for initialization to finish:
     boolean inited = client.getDataSourceStatusProvider().waitFor(
         DataSourceStatusProvider.State.VALID, Duration.ofSeconds(10));
     if (!inited) {
         // do whatever is appropriate if initialization has timed out
     }

        This constructor can throw unchecked exceptions if it is immediately apparent that the SDK cannot work with these parameters. For instance, if the SDK key contains a non-printable character that cannot be used in an HTTP header, it will throw an IllegalArgumentException since the SDK key is normally sent to LaunchDarkly in an HTTP header and no such value could possibly be valid. Similarly, a null value for a non-nullable parameter may throw a NullPointerException. The constructor will not throw an exception for any error condition that could only be detected after making a request to LaunchDarkly (such as an SDK key that is simply wrong despite being valid ASCII, so it is invalid but not illegal); those are logged and treated as an unsuccessful initialization, as described above.

        Parameters:
        sdkKey - the SDK key for your LaunchDarkly environment
        config - a client configuration object
        Throws:
        java.lang.IllegalArgumentException - if a parameter contained a grossly malformed value; for security reasons, in case of an illegal SDK key, the exception message does not include the key
        java.lang.NullPointerException - if a non-nullable parameter was null
        See Also:
        LDClient(String, LDConfig)

    • Method Detail

      • isInitialized

        public boolean isInitialized()
        Description copied from interface: LDClientInterface
        Tests whether the client is ready to be used.
        Specified by:
        isInitialized in interface LDClientInterface
        Returns:
        true if the client is ready, or false if it is still initializing

      • trackData

        public void trackData​(java.lang.String eventName,
                      LDUser user,
                      LDValue data)
        Description copied from interface: LDClientInterface
        Tracks that a user performed an event, and provides additional custom data.
        Specified by:
        trackData in interface LDClientInterface
        Parameters:
        eventName - the name of the event
        user - the user that performed the event
        data - an LDValue containing additional data associated with the event

      • trackMetric

        public void trackMetric​(java.lang.String eventName,
                        LDUser user,
                        LDValue data,
                        double metricValue)
        Description copied from interface: LDClientInterface
        Tracks that a user performed an event, and provides an additional numeric value for custom metrics.
        Specified by:
        trackMetric in interface LDClientInterface
        Parameters:
        eventName - the name of the event
        user - the user that performed the event
        data - an LDValue containing additional data associated with the event; if not applicable, you may pass either null or LDValue.ofNull()
        metricValue - a numeric value used by the LaunchDarkly experimentation feature in numeric custom metrics. Can be omitted if this event is used by only non-numeric metrics. This field will also be returned as part of the custom event for Data Export.

      • allFlagsState

        public FeatureFlagsState allFlagsState​(LDUser user,
                                       FlagsStateOption... options)
        Description copied from interface: LDClientInterface
        Returns an object that encapsulates the state of all feature flags for a given user, including the flag values and also metadata that can be used on the front end. This method does not send analytics events back to LaunchDarkly.

        The most common use case for this method is to bootstrap a set of client-side feature flags from a back-end service.

        Specified by:
        allFlagsState in interface LDClientInterface
        Parameters:
        user - the end user requesting the feature flags
        options - optional FlagsStateOption values affecting how the state is computed - for instance, to filter the set of flags to only include the client-side-enabled ones
        Returns:
        a FeatureFlagsState object (will never be null; see FeatureFlagsState.isValid()

      • boolVariation

        public boolean boolVariation​(java.lang.String featureKey,
                             LDUser user,
                             boolean defaultValue)
        Description copied from interface: LDClientInterface
        Calculates the value of a feature flag for a given user.
        Specified by:
        boolVariation in interface LDClientInterface
        Parameters:
        featureKey - the unique key for the feature flag
        user - the end user requesting the flag
        defaultValue - the default value of the flag
        Returns:
        the variation for the given user, or defaultValue if there is an error fetching the variation or the flag doesn't exist

      • intVariation

        public int intVariation​(java.lang.String featureKey,
                        LDUser user,
                        int defaultValue)
        Description copied from interface: LDClientInterface
        Calculates the integer value of a feature flag for a given user.

        If the flag variation has a numeric value that is not an integer, it is rounded toward zero (truncated).

        Specified by:
        intVariation in interface LDClientInterface
        Parameters:
        featureKey - the unique key for the feature flag
        user - the end user requesting the flag
        defaultValue - the default value of the flag
        Returns:
        the variation for the given user, or defaultValue if there is an error fetching the variation or the flag doesn't exist

      • doubleVariation

        public double doubleVariation​(java.lang.String featureKey,
                              LDUser user,
                              double defaultValue)
        Description copied from interface: LDClientInterface
        Calculates the floating point numeric value of a feature flag for a given user.
        Specified by:
        doubleVariation in interface LDClientInterface
        Parameters:
        featureKey - the unique key for the feature flag
        user - the end user requesting the flag
        defaultValue - the default value of the flag
        Returns:
        the variation for the given user, or defaultValue if there is an error fetching the variation or the flag doesn't exist

      • stringVariation

        public java.lang.String stringVariation​(java.lang.String featureKey,
                                        LDUser user,
                                        java.lang.String defaultValue)
        Description copied from interface: LDClientInterface
        Calculates the String value of a feature flag for a given user.
        Specified by:
        stringVariation in interface LDClientInterface
        Parameters:
        featureKey - the unique key for the feature flag
        user - the end user requesting the flag
        defaultValue - the default value of the flag
        Returns:
        the variation for the given user, or defaultValue if there is an error fetching the variation or the flag doesn't exist

      • jsonValueVariation

        public LDValue jsonValueVariation​(java.lang.String featureKey,
                                  LDUser user,
                                  LDValue defaultValue)
        Description copied from interface: LDClientInterface
        Calculates the LDValue value of a feature flag for a given user.
        Specified by:
        jsonValueVariation in interface LDClientInterface
        Parameters:
        featureKey - the unique key for the feature flag
        user - the end user requesting the flag
        defaultValue - the default value of the flag
        Returns:
        the variation for the given user, or defaultValue if there is an error fetching the variation or the flag doesn't exist; will never be a null reference, but may be LDValue.ofNull()

      • boolVariationDetail

        public EvaluationDetail<java.lang.Boolean> boolVariationDetail​(java.lang.String featureKey,
                                                               LDUser user,
                                                               boolean defaultValue)
        Description copied from interface: LDClientInterface
        Calculates the value of a feature flag for a given user, and returns an object that describes the way the value was determined. The reason property in the result will also be included in analytics events, if you are capturing detailed event data for this flag.
        Specified by:
        boolVariationDetail in interface LDClientInterface
        Parameters:
        featureKey - the unique key for the feature flag
        user - the end user requesting the flag
        defaultValue - the default value of the flag
        Returns:
        an EvaluationDetail object

      • intVariationDetail

        public EvaluationDetail<java.lang.Integer> intVariationDetail​(java.lang.String featureKey,
                                                              LDUser user,
                                                              int defaultValue)
        Description copied from interface: LDClientInterface
        Calculates the value of a feature flag for a given user, and returns an object that describes the way the value was determined. The reason property in the result will also be included in analytics events, if you are capturing detailed event data for this flag.

        If the flag variation has a numeric value that is not an integer, it is rounded toward zero (truncated).

        Specified by:
        intVariationDetail in interface LDClientInterface
        Parameters:
        featureKey - the unique key for the feature flag
        user - the end user requesting the flag
        defaultValue - the default value of the flag
        Returns:
        an EvaluationDetail object

      • doubleVariationDetail

        public EvaluationDetail<java.lang.Double> doubleVariationDetail​(java.lang.String featureKey,
                                                                LDUser user,
                                                                double defaultValue)
        Description copied from interface: LDClientInterface
        Calculates the value of a feature flag for a given user, and returns an object that describes the way the value was determined. The reason property in the result will also be included in analytics events, if you are capturing detailed event data for this flag.
        Specified by:
        doubleVariationDetail in interface LDClientInterface
        Parameters:
        featureKey - the unique key for the feature flag
        user - the end user requesting the flag
        defaultValue - the default value of the flag
        Returns:
        an EvaluationDetail object

      • stringVariationDetail

        public EvaluationDetail<java.lang.String> stringVariationDetail​(java.lang.String featureKey,
                                                                LDUser user,
                                                                java.lang.String defaultValue)
        Description copied from interface: LDClientInterface
        Calculates the value of a feature flag for a given user, and returns an object that describes the way the value was determined. The reason property in the result will also be included in analytics events, if you are capturing detailed event data for this flag.
        Specified by:
        stringVariationDetail in interface LDClientInterface
        Parameters:
        featureKey - the unique key for the feature flag
        user - the end user requesting the flag
        defaultValue - the default value of the flag
        Returns:
        an EvaluationDetail object

      • isFlagKnown

        public boolean isFlagKnown​(java.lang.String featureKey)
        Description copied from interface: LDClientInterface
        Returns true if the specified feature flag currently exists.
        Specified by:
        isFlagKnown in interface LDClientInterface
        Parameters:
        featureKey - the unique key for the feature flag
        Returns:
        true if the flag exists

      • getDataStoreStatusProvider

        public DataStoreStatusProvider getDataStoreStatusProvider()
        Description copied from interface: LDClientInterface
        Returns an interface for tracking the status of a persistent data store.

        The DataStoreStatusProvider has methods for checking whether the data store is (as far as the SDK knows) currently operational, tracking changes in this status, and getting cache statistics. These are only relevant for a persistent data store; if you are using an in-memory data store, then this method will return a stub object that provides no information.

        Specified by:
        getDataStoreStatusProvider in interface LDClientInterface
        Returns:
        a DataStoreStatusProvider

      • close

        public void close()
           throws java.io.IOException
        Description copied from interface: LDClientInterface
        Closes the LaunchDarkly client event processing thread. This should only be called on application shutdown.
        Specified by:
        close in interface java.lang.AutoCloseable
        Specified by:
        close in interface java.io.Closeable
        Specified by:
        close in interface LDClientInterface
        Throws:
        java.io.IOException - if an exception is thrown by one of the underlying network services

      • isOffline

        public boolean isOffline()
        Description copied from interface: LDClientInterface
        Returns true if the client is in offline mode.
        Specified by:
        isOffline in interface LDClientInterface
        Returns:
        whether the client is in offline mode

      • alias

        public void alias​(LDUser user,
                  LDUser previousUser)
        Description copied from interface: LDClientInterface
        Associates two users for analytics purposes. This can be helpful in the situation where a person is represented by multiple LaunchDarkly users. This may happen, for example, when a person initially logs into an application-- the person might be represented by an anonymous user prior to logging in and a different user after logging in, as denoted by a different user key.
        Specified by:
        alias in interface LDClientInterface
        Parameters:
        user - the newly identified user.
        previousUser - the previously identified user.

      • version

        public java.lang.String version()
        Returns the current version string of the client library.
        Specified by:
        version in interface LDClientInterface
        Returns:
        a version string conforming to Semantic Versioning (http://semver.org)