Package org.apache.cxf.clustering

Class LoadDistributorTargetSelector

java.lang.Object
org.apache.cxf.endpoint.AbstractConduitSelector
org.apache.cxf.clustering.FailoverTargetSelector
org.apache.cxf.clustering.LoadDistributorTargetSelector
All Implemented Interfaces:
Closeable, AutoCloseable, org.apache.cxf.endpoint.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 Details

    • LoadDistributorTargetSelector

      public LoadDistributorTargetSelector()
      Normal constructor.

    • LoadDistributorTargetSelector

      public LoadDistributorTargetSelector(String clientBootstrapAddress)

    • LoadDistributorTargetSelector

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

  • Method Details

    • isFailover

      public boolean isFailover()

    • setFailover

      public void setFailover(boolean failover)

    • getLogger

      protected Logger getLogger()
      Overrides:
      getLogger in class FailoverTargetSelector
      Returns:
      the logger to use

    • selectConduit

      public org.apache.cxf.transport.Conduit selectConduit(org.apache.cxf.message.Message message)
      Called when a Conduit is actually required.
      Specified by:
      selectConduit in interface org.apache.cxf.endpoint.ConduitSelector
      Overrides:
      selectConduit in class FailoverTargetSelector
      Parameters:
      message -
      Returns:
      the Conduit to use for mediation of the message

    • getFailoverTarget

      protected org.apache.cxf.endpoint.Endpoint getFailoverTarget(org.apache.cxf.message.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.

    • requiresFailover

      protected boolean requiresFailover(org.apache.cxf.message.Exchange exchange, Exception ex)
      Description copied from class: FailoverTargetSelector
      Check if the exchange is suitable for a failover.
      Overrides:
      requiresFailover in class FailoverTargetSelector
      Parameters:
      exchange - the current Exchange
      Returns:
      boolean true if a failover should be attempted