Package com.mysql.cj.jdbc.ha.ca

Interface TopologyService

All Known Implementing Classes:
AuroraTopologyService
public interface TopologyService
It's a generic interface for all topology services. It's expected that every implementation of topology service covers different cluster types or cluster deployment.

It's expected that each instance of ClusterAwareConnectionProxy uses it's own instance of topology service.

  • Method Details

    • setClusterId

      void setClusterId​(java.lang.String clusterId)
      Set unique cluster identifier for topology service instance.

      Cluster could be accessed through different connection strings like IP address, cluster dns endpoint, instance dns endpoint, custom domain alias (CNAME), etc. Cluster Id can be any string that unique identify a cluster despite the way it's been accessed.

      Parameters:
      clusterId - Cluster unique identifier.

    • setClusterInstanceTemplate

      void setClusterInstanceTemplate​(HostInfo clusterInstanceTemplate)
      Sets host details common to each instance in the cluster, including the host dns pattern. "?" (question mark) in a host dns pattern will be replaced with a host instance name to form a fully qualified dns host endpoint.

      Examples: "?.mydomain.com", "db-instance.?.mydomain.com"

      Parameters:
      clusterInstanceTemplate - Cluster instance details including host dns pattern.

    • getTopology

      java.util.List<HostInfo> getTopology​(JdbcConnection conn, boolean forceUpdate)
      Get cluster topology. A writer host is always at position 0.
      Parameters:
      conn - A connection to database to fetch the latest topology, if needed.
      forceUpdate - If true, it forces a service to ignore cached copy of topology and to fetch a fresh one.
      Returns:
      A list of hosts that describes cluster topology. A writer is always at position 0. Returns an empty list if topology isn't available or is invalid (doesn't contain a writer).

    • getCachedTopology

      java.util.List<HostInfo> getCachedTopology()
      Get cached topology.
      Returns:
      List of hosts that represents topology. If there's no topology in cache, it returns null.

    • getLastUsedReaderHost

      HostInfo getLastUsedReaderHost()
      Get details about the most recent reader that the driver has successfully connected to.
      Returns:
      The host details of the most recent reader connection.

    • setLastUsedReaderHost

      void setLastUsedReaderHost​(HostInfo reader)
      Set details about the most recent reader that the driver has connected to.
      Parameters:
      reader - A reader host.

    • getHostByName

      HostInfo getHostByName​(JdbcConnection conn)
      Return the HostInfo object that is associated with a provided connection from the topology host list.
      Parameters:
      conn - A connection to database.
      Returns:
      The HostInfo object from the topology host list. Returns null if the connection host is not found in the latest topology.

    • getDownHosts

      java.util.Set<java.lang.String> getDownHosts()
      Get a set of instance names that were marked down.
      Returns:
      A set of instance dns names with port. For example: "instance-1.my-domain.com:3306".

    • addToDownHostList

      void addToDownHostList​(HostInfo downHost)
      Mark host as down. Host stays marked down until next topology refresh.
      Parameters:
      downHost - The HostInfo object representing the host to mark as down

    • removeFromDownHostList

      void removeFromDownHostList​(HostInfo host)
      Unmark host as down. The host is removed from the list of down hosts
      Parameters:
      host - The HostInfo object representing the host to remove from the list of down hosts

    • isMultiWriterCluster

      boolean isMultiWriterCluster()
      Check if topology belongs to multi-writer cluster.
      Returns:
      True, if it's multi-writer cluster.

    • setRefreshRate

      void setRefreshRate​(int refreshRate)
      Set new topology refresh rate. Topology is considered valid (up to date) within provided duration of time.
      Parameters:
      refreshRate - Topology refresh rate in millis.

    • clearAll

      void clearAll()
      Clear topology service for all clusters.

    • clear

      void clear()
      Clear topology service for the current cluster.