wt.manager
Class RemoteServerManager

java.lang.Object
  wt.manager.RemoteServerManager

public class RemoteServerManager

extends Object

Class that provides access to a remote server manager. Instances of this class are local (non-remote) objects that encapsulate the communication with a remote server manager object. This encapsulation includes object location, and automatic recovery from communication errors.

The local object represents the "concept" of a remote server manager, not a particular instance of the remote server object. This allows the local object to manage connecting to a server object, and reconnecting to new server objects during error recovery.

Supported API: true
Extendable: false

Field Summary

private static Hashtable	codebaseMap
protected Registry	currentRegistry
protected ServerManager	currentServerManager
private static Object	lock
private static int	MARSHAL_RETRY
private static int	OTHER_RETRY
private static Object	remoteServerManagerKey
private static String	RESOURCE
private URL	serverCodebase
static boolean	ServerFlag 0 Server Manager flag - used to control conditional behavior in classes that may run in the server manager as well as outside the server manager.
private static boolean	VERBOSE_CLIENT

Constructor Summary

protected

RemoteServerManager(URL server_codebase) Construct a new RemoteServerManager object.

Method Summary

Vector	getAllServers(String service_name) Get all servers for the requested service_name.
static RemoteServerManager	getDefault() Get default instance of RemoteServerManager.
ServerManagerInfo	getInfo() Get usage information.
static RemoteServerManager	getInstance(URL server_codebase) Get instance of RemoteServermanager corresponding to the given server codebase URL.
protected String	getMessage(String key) Supported API: false
Remote	getNextServer(String service_name, Remote server) Get the next available server for the requested service_name.
protected Registry	getRegistry(Registry prev_registry) Get a remote registry instance associated with this RemoteMethodServer object.
Remote	getServer(String service_name) Get reference to a remote server object.
Remote	getServer(String service_name, int start_num) Get reference to a remote server object.
protected ServerManager	getServerManager(ServerManager prev_server_manager) Get a remote server manager instance associated with this RemoteServerManager object.
static void	main(String[] args) Simple tester Displays info from the default server.
private static RemoteException	newRemoteException(String msg, Throwable t)
void	ping() A no-op method available for testing communication.
private static void	printRegistryException(RemoteException e)
private static void	printRemoteException(RemoteException e)
void	registerServer(String service_name, Remote server) Register a new server instance.
void	reportDeadServer(String service_name, Remote server) Report a bad remote server reference.
void	reportDeadServer(String service_name, Remote server, Exception report_exception) Report a bad remote server reference.
private void	reportIncompatibleCodebase(String local_version, String server_version)
(package private) void	setServerManager(ServerManager server_manager)
void	stop() Stop the remote server manager.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

RESOURCE

private static final String RESOURCE

See Also:

Constant Field Values

ServerFlag

public static boolean ServerFlag

0 Server Manager flag - used to control conditional behavior in classes that may run in the server manager as well as outside the server manager. Should be set to true only within the server manager itself.

MARSHAL_RETRY

private static final int MARSHAL_RETRY

OTHER_RETRY

private static final int OTHER_RETRY

VERBOSE_CLIENT

private static final boolean VERBOSE_CLIENT

remoteServerManagerKey

private static final Object remoteServerManagerKey

codebaseMap

private static Hashtable codebaseMap

lock

private static Object lock

serverCodebase

private URL serverCodebase

currentRegistry

protected Registry currentRegistry

currentServerManager

protected ServerManager currentServerManager

Constructor Detail

RemoteServerManager

protected RemoteServerManager(URL server_codebase)

Construct a new RemoteServerManager object. The server_codebase argument is used to load server properties necessary to establish communication with the remote server manager.

Supported API: false

Parameters:

server_codebase - the server codebase URL

Method Detail

setServerManager

void setServerManager(ServerManager server_manager)

getInstance

public static RemoteServerManager getInstance(URL server_codebase)

Get instance of RemoteServermanager corresponding to the given server codebase URL.

Supported API: true

Parameters:

server_codebase - the server codebase URL

getDefault

public static RemoteServerManager getDefault()

Get default instance of RemoteServerManager. The default instance is the one corresponding to the server codebase of the current thread as returned by the WTProperties class.

Supported API: true

See Also:

WTProperties

registerServer

public void registerServer(String service_name,
                           Remote server)
                    throws RemoteException

Register a new server instance. Called when servers are started and initialized. Only servers on the server manager's local host are allowed to register.

Supported API: false

Parameters:

service_name - service name corresponding to this remote server instance

server - the remote server instance

Throws:

RemoteException

getServer

public Remote getServer(String service_name)
                 throws RemoteException

Get reference to a remote server object. A service name is used to identify the type of server desired. If no server is available, one will be started by the server manager.

Supported API: true

Parameters:

service_name - the corresponding service name

Returns:

a remote server reference

Throws:

RemoteException

getServer

public Remote getServer(String service_name,
                        int start_num)
                 throws RemoteException

Get reference to a remote server object. A service name is used to identify the type of server desired. If no server is available, one will be started by the server manager.

Supported API: true

Parameters:

service_name - the corresponding service name

start_num - used in start up of multiple servers for this service

Returns:

a remote server reference

Throws:

RemoteException

getNextServer

public Remote getNextServer(String service_name,
                            Remote server)
                     throws RemoteException

Get the next available server for the requested service_name. The previous server is used for a reference and if no other server is available, null is returned. This method is used by servers that wish to redirect clients to other servers when doing load leveling.

Supported API: true

Parameters:

service_name - corresponding service name

server - previous server

Throws:

RemoteException

getAllServers

public Vector getAllServers(String service_name)
                     throws RemoteException

Get all servers for the requested service_name.

Supported API: true

Parameters:

service_name - corresponding service name

Returns:

a vector of remote server references

Throws:

RemoteException

reportDeadServer

public void reportDeadServer(String service_name,
                             Remote server)
                      throws RemoteException

Report a bad remote server reference. A bad reference is one that is no longer alive or is throwing unexpected exceptions when trying to invoke services.

Supported API: false

Parameters:

service_name - corresponding service name

server - the remote server reference

Throws:

RemoteException

reportDeadServer

public void reportDeadServer(String service_name,
                             Remote server,
                             Exception report_exception)
                      throws RemoteException

Report a bad remote server reference. A bad reference is one that is no longer alive or is throwing unexpected exceptions when trying to invoke services.

Supported API: false

Parameters:

service_name - corresponding service name

server - the remote server reference

report_exception - exception to report

Throws:

RemoteException

getInfo

public ServerManagerInfo getInfo()
                          throws RemoteException

Get usage information.

Supported API: false

Throws:

RemoteException

ping

public void ping()
          throws RemoteException

A no-op method available for testing communication.

Supported API: true

Throws:

RemoteException

stop

public void stop()
          throws RemoteException

Stop the remote server manager. Only calls originating from the server manager's local host will be honored.

Supported API: true

Throws:

RemoteException

getServerManager

protected ServerManager getServerManager(ServerManager prev_server_manager)
                                  throws RemoteException

Get a remote server manager instance associated with this RemoteServerManager object. This is used to establish the association with a remote server manager object, or to reestablish a new association during exception handling.

Supported API: false

Parameters:

prev_server_manager - previous remote instance (null to force new association)

Throws:

RemoteException

printRemoteException

private static void printRemoteException(RemoteException e)

printRegistryException

private static void printRegistryException(RemoteException e)

getRegistry

protected Registry getRegistry(Registry prev_registry)
                        throws RemoteException

Get a remote registry instance associated with this RemoteMethodServer object. This is used to establish the association with a remote registry object, or to reestablish a new association during exception handling.

Supported API: false

Parameters:

prev_registry - previous remote instance (null to force new association)

Throws:

RemoteException

reportIncompatibleCodebase

private void reportIncompatibleCodebase(String local_version,
                                        String server_version)

newRemoteException

private static RemoteException newRemoteException(String msg,
                                                  Throwable t)

getMessage

protected String getMessage(String key)

Supported API: false

main

public static void main(String[] args)
                 throws RemoteException

Simple tester Displays info from the default server.

Supported API: true

Throws:

RemoteException