Package org.eclipse.persistence.sessions.coordination

Interface CommandManager

All Known Implementing Classes:
RemoteCommandManager
public interface CommandManager

Purpose: Provide an interface that clients can use to invoke remote commands on other EclipseLink instances, or on other applications that may want to receive and process EclipseLink commands.

Description: This is the main interface that is used to send and receive remote commands in a EclipseLink cluster. The sequence of remote command execution is as follows:

  1. CommandProcessor creates a command and gives it to its local CommandManager to send to remote services.
  2. CommandManager uses its CommandConverter to convert the command into a TopLink Command object
  3. CommandManager then uses its TransportManager to send the Command to all other known cluster members that are subscribing to the same channel
  4. Each remote TransportManager receives the Command and passes it off to the CommandManager
  5. Each CommandManager uses its local CommandConverter to convert the command into a format appropriate to its application (CommandProcessor)
  6. Each CommandManager invokes its local CommandProcessor and passes it the command (formatted the way that the application-specified converter left it in) to be executed. If the CommandProcessor is a EclipseLink session then the executeWithSession method will be invoked on the command.

Responsibilities:

  • Invoke the DiscoveryManager to establish the EclipseLink cluster
  • Propagate remote command to EclipseLink cluster
  • Delegate processing command to its CommandProssesor
  • Convert command to appropriate format for sending to EclipseLink cluster or its command processor
See Also:
Author:
Steven Vo

  • Method Summary

    Modifier and Type
    Method
    Description
    String
    getChannel()
    PUBLIC: Return the service channel for this command manager.
    CommandConverter
    getCommandConverter()
    PUBLIC: Return the converter instance used to convert between TopLink Command objects and an application command format.
    CommandProcessor
    getCommandProcessor()
    PUBLIC: Return the command processor that processes commands received from the cluster.
    DiscoveryManager
    getDiscoveryManager()
    PUBLIC: Return the discovery manager that manages membership in the EclipseLink cluster.
    TransportManager
    getTransportManager()
    PUBLIC: Return the transport manager that manages sending and receiving of remote commands.
    String
    getUrl()
    PUBLIC: Return the URL for this command manager.
    void
    initialize()
    PUBLIC: Initialize the remote command manager.
    boolean
    isCommandProcessorASession()
    ADVANCE: Return whether this commandProcessor is a EclipseLink session or not.
    void
    propagateCommand(Object command)
    ADVANCED: Propagate a remote command to all remote RCM services participating in the EclipseLink cluster.
    void
    setChannel(String channel)
    ADVANCED: Set the service channel for this command manager.
    void
    setCommandConverter(CommandConverter commandConverter)
    ADVANCED: Set the converter instance that will be invoked by this CommandProcessor to convert commands from their application command format into EclipseLink Command objects before being propagated to remote command manager services.
    void
    setCommandProcessor(CommandProcessor commandProcessor)
    ADVANCED: Set the command processor that will be invoked to process commands.
    void
    setShouldPropagateAsynchronously(boolean asyncMode)
    ADVANCED: Set whether this command manager should propagate commands synchronously or asynchronously.
    void
    setTransportManager(TransportManager newTransportManager)
    ADVANCED: Set a specific transport manager to manage sending and receiving of remote commands.
    void
    setUrl(String url)
    ADVANCED: Set the URL for this command manager.
    boolean
    shouldPropagateAsynchronously()
    PUBLIC: Return whether this command manager should propagate commands synchronously or asynchronously.
    void
    shutdown()
    PUBLIC: Shut down the remote command manager.

  • Method Details

    • initialize

      void initialize()
      PUBLIC: Initialize the remote command manager. This will also trigger the DiscoveryManager to start establishing the EclipseLink cluster.

    • shutdown

      void shutdown()
      PUBLIC: Shut down the remote command manager. This will also trigger the DiscoveryManager to stop. NOTE: Although this call initiates the shutdown process, no guarantees are made as to when it will actually complete.

    • getUrl

      String getUrl()
      PUBLIC: Return the URL for this command manager.
      Returns:
      The URL String for this CommandManager

    • setUrl

      void setUrl(String url)
      ADVANCED: Set the URL for this command manager.
      Parameters:
      url - The URL String for this CommandManager

    • getChannel

      String getChannel()
      PUBLIC: Return the service channel for this command manager. All command managers with the same service channel will send and receive commands from each other. Commands sent on other service channels will not be exchanged with this command manager.
      Returns:
      The service channel String subscribed to by this CommandManager

    • setChannel

      void setChannel(String channel)
      ADVANCED: Set the service channel for this command manager. All command managers with the same service channel will send and receive commands from each other. Commands sent on other service channels will not be exchanged with this command manager.
      Parameters:
      channel - The service channel subscribed to by this CommandManager

    • propagateCommand

      void propagateCommand(Object command)
      ADVANCED: Propagate a remote command to all remote RCM services participating in the EclipseLink cluster.
      Parameters:
      command - An object representing a TopLink command

    • getCommandProcessor

      CommandProcessor getCommandProcessor()
      PUBLIC: Return the command processor that processes commands received from the cluster.
      Returns:
      An implementation instance of CommandProcessor

    • setCommandProcessor

      void setCommandProcessor(CommandProcessor commandProcessor)
      ADVANCED: Set the command processor that will be invoked to process commands. EclipseLink applications can implement this interface in order to receive remote commands from a EclipseLink cluster.
      Parameters:
      commandProcessor - The intended processor of remote commands

    • setTransportManager

      void setTransportManager(TransportManager newTransportManager)
      ADVANCED: Set a specific transport manager to manage sending and receiving of remote commands.
      Parameters:
      newTransportManager - An instance of the desired transport manager type

    • getTransportManager

      TransportManager getTransportManager()
      PUBLIC: Return the transport manager that manages sending and receiving of remote commands.
      Returns:
      The TransportManager instance being used by this CommandManager

    • getDiscoveryManager

      DiscoveryManager getDiscoveryManager()
      PUBLIC: Return the discovery manager that manages membership in the EclipseLink cluster.
      Returns:
      The DiscoveryManager instance being used by this CommandManager

    • getCommandConverter

      CommandConverter getCommandConverter()
      PUBLIC: Return the converter instance used to convert between TopLink Command objects and an application command format.
      Returns:
      The converter being used by this CommandManager

    • setCommandConverter

      void setCommandConverter(CommandConverter commandConverter)
      ADVANCED: Set the converter instance that will be invoked by this CommandProcessor to convert commands from their application command format into EclipseLink Command objects before being propagated to remote command manager services. The converter will also be invoked to convert EclipseLink Command objects into application format before being sent to the CommandProcessor for execution.
      Parameters:
      commandConverter - The converter to be used by this CommandManager

    • shouldPropagateAsynchronously

      boolean shouldPropagateAsynchronously()
      PUBLIC: Return whether this command manager should propagate commands synchronously or asynchronously. If set to synchronous propagation then propagateCommand() will not return to the caller until the command has been executed on all of the services in the cluster. In asynchronous mode the command manager will create a separate thread for each of the remote service executions, and then promptly return to the caller.

    • setShouldPropagateAsynchronously

      void setShouldPropagateAsynchronously(boolean asyncMode)
      ADVANCED: Set whether this command manager should propagate commands synchronously or asynchronously. If set to synchronous propagation then propagateCommand() will not return to the caller until the command has been executed on all of the services in the cluster. In asynchronous mode the command manager will create a separate thread for each of the remote service executions, and then promptly return to the caller.

    • isCommandProcessorASession

      boolean isCommandProcessorASession()
      ADVANCE: Return whether this commandProcessor is a EclipseLink session or not.