Package org.apache.cxf.clustering

Class LoadDistributorTargetSelector

  • All Implemented Interfaces:
    Closeable, AutoCloseable, ConduitSelector
    public class LoadDistributorTargetSelector
extends FailoverTargetSelector
    The LoadDistributorTargetSelector attempts to do the same job as the FailoverTargetSelector, but to choose an alternate target on every request rather than just when a fault occurs. The LoadDistributorTargetSelector uses the same FailoverStrategy interface as the FailoverTargetSelector, but has a few significant limitations: 1. Because the LoadDistributorTargetSelector needs to maintain a list of targets between calls it has to obtain that list without reference to a Message. Most FailoverStrategy classes can support this for addresses, but it cannot be supported for endpoints. If the list of targets cannot be obtained without reference to a Message then the list will still be obtained but it will be specific to the Message and thus discarded after this message has been processed. As a consequence, if the strategy chosen is a simple sequential one the first item in the list will be chosen every time. Conclusion: Be aware that if you are working with targets that are dependent on the Message the process will be less efficient and that the SequentialStrategy will not distribute the load at all. 2. The AbstractStaticFailoverStrategy base class excludes the 'default' endpoint from the list of alternate endpoints. If alternate endpoints (as opposed to alternate addresses) are to be used you should probably ensure that your FailoverStrategy overrides getAlternateEndpoints and calls getEndpoints with acceptCandidatesWithSameAddress = true.

    • Constructor Detail

      • LoadDistributorTargetSelector

        public LoadDistributorTargetSelector()
        Normal constructor.

      • LoadDistributorTargetSelector

        public LoadDistributorTargetSelector​(String clientBootstrapAddress)

      • LoadDistributorTargetSelector

        public LoadDistributorTargetSelector​(Conduit c)
        Constructor, allowing a specific conduit to override normal selection.
        Parameters:
        c - specific conduit

    • Method Detail

      • isFailover

        public boolean isFailover()

      • setFailover

        public void setFailover​(boolean failover)

      • getFailoverTarget

        protected Endpoint getFailoverTarget​(Exchange exchange,
                                     FailoverTargetSelector.InvocationContext invocation)
        Get the failover target endpoint, if a suitable one is available.
        Overrides:
        getFailoverTarget in class FailoverTargetSelector
        Parameters:
        exchange - the current Exchange
        invocation - the current InvocationContext
        Returns:
        a failover endpoint if one is available Note: The only difference between this and the super implementation is that the current (failed) address is removed from the list set of alternates, it could be argued that that change should be in the super implementation but I'm not sure of the impact.