de.fhg.igd.atlas.core
Class LSClient

java.lang.Object
  de.fhg.igd.semoa.service.AbstractService
      de.fhg.igd.atlas.core.LSClient

All Implemented Interfaces:

AgentFilter, Listener, Runnable, Service

public class LSClient

extends AbstractService

implements Runnable, Listener, AgentFilter

Provides an interface between the SeMoA server and the location service. All important agent events are caught by this Location Service Client (LSClient) to initialize, update or delete the location entries of an existing Location Service Proxy (LSProxy) respectively the corresponding Location Service Server (LSServer). A refresh daemon is installed to refresh these entries periodically after certain time intervals while they are running on the local SeMoA server. Moreover the LSClientService is installed, which is used by this component and can be used by local agents to lookup the current location of other agents.

Version:

"$Id: LSClient.java 1913 2007-08-08 02:41:53Z jpeters $"

Author:

Jan Peters

See Also:

LSClientService

Nested Class Summary

Nested classes inherited from class de.fhg.igd.semoa.server.AgentFilter

AgentFilter.In, AgentFilter.Out

Field Summary

protected LSClientServiceImpl	clientService_ The reference to the LSClientService interface.
private static String[]	DEPEND_ The dependencies to other objects in the global Environment.
private static Logger	log_ The Logger instance for this class
static String	OPT_DESCR The ArgsParser option descriptor for the case that this class is initiated from command line.
protected long	proxyRefreshTime_ The time interval in milli seconds after that a proxy refresh of all local agent entries is initiated.
protected Thread	refreshThread_ Thread that provides a periodic refresh of all local agent entries.
protected long	serverRefreshTime_ The time interval in milli seconds after that a global refresh of all local agent entries is initiated.

Fields inherited from class de.fhg.igd.semoa.service.AbstractService

REV_POSTFIX, REV_PREFIX

Constructor Summary

protected

LSClient() Creates an instance of this class and initializes the LSClientService with the given parameters.

Method Summary

String	author() Returns the String with the author's name.
protected boolean	checkLANLocality(Ticket ticket) Checks the LAN locality of the destination URLs of the given ticket.
String[]	dependencies() Returns the dependencies of this service as described in Service.
ErrorCode	filter(AgentContext agentContext) Called from the information filter, which has to be installed within the incoming agent filter pipeline, whenever a new incomming agent has been detected.
protected void	globalRefreshAllAgents() Refreshes the location entries on the LSServer of all agents, which can be found on the local system through localLookupAll.
String	info() Returns the String with the service's short description.
protected boolean	initLSInfrastructure(String configFile) Initialize the location service infrastructure of distributed LS-Servers by parsing the given configuration file.
protected boolean	initLSInfrastructure(URL configLdapServer) Initialize the location service infrastructure of distributed LS-Servers by requesting the configuration from a LDAP server with the given URL.
static void	main(String[] argv) Initializes the LSClient from command line.
void	notifiedOf(Object obj) This method is called with the event that caused the notification.
protected void	proxyInvalidate(AgentContext ctx) Invalidates the proxy location entry for the agent with the given agent context.
protected void	proxyRefreshAllAgents() Refreshes the location entries on the LSProxy of all agents which can be found on the local system through localLokupAll.
protected void	register(AgentContext ctx, boolean init) Registers this system as new location for the agent with the given agent context.
protected void	registerDelete(AgentContext ctx) Deletes the location entry for the agent with the given agent context.
String	revision() Returns the revision number of this class as a string.
void	run() This method represents the functionality of the refresh daemon.

Methods inherited from class de.fhg.igd.semoa.service.AbstractService

checkDependencies, docs, doPrivileged, doPrivileged, getACC, getEnvironment, majorVersion, minorVersion, toString

Methods inherited from class java.lang.Object

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

Field Detail

log_

private static Logger log_

The Logger instance for this class

DEPEND_

private static final String[] DEPEND_

The dependencies to other objects in the global Environment.

OPT_DESCR

public static final String OPT_DESCR

The ArgsParser option descriptor for the case that this class is initiated from command line.

See Also:

Constant Field Values

clientService_

protected LSClientServiceImpl clientService_

The reference to the LSClientService interface.

proxyRefreshTime_

protected long proxyRefreshTime_

The time interval in milli seconds after that a proxy refresh of all local agent entries is initiated.

serverRefreshTime_

protected long serverRefreshTime_

The time interval in milli seconds after that a global refresh of all local agent entries is initiated.

refreshThread_

protected Thread refreshThread_

Thread that provides a periodic refresh of all local agent entries.

Constructor Detail

LSClient

protected LSClient()

Creates an instance of this class and initializes the LSClientService with the given parameters. Moreover the refresh daemon is started.

Method Detail

initLSInfrastructure

protected boolean initLSInfrastructure(String configFile)

Initialize the location service infrastructure of distributed LS-Servers by parsing the given configuration file. If configFile is null, no server will be initialized.

Parameters:

configFile - The name the configuration file containing the configuration of the location service infrastructure.

Returns:

true, if the given configuration file has been parsed successfully, false otherwise.

initLSInfrastructure

protected boolean initLSInfrastructure(URL configLdapServer)

Initialize the location service infrastructure of distributed LS-Servers by requesting the configuration from a LDAP server with the given URL. If configLdapServer is null, no server will be initialized.

Parameters:

configLdapServer - The URL of the ldap server maintaining the configuration of the location service infrastructure.

Returns:

true, if the configuration has been received successfully from the given LDAP server, false otherwise.

info

public String info()

Returns the String with the service's short description.

Specified by:

info in interface Service

Specified by:

info in class AbstractService

Returns:

The String with the service's short description.

author

public String author()

Returns the String with the author's name.

Specified by:

author in interface Service

Specified by:

author in class AbstractService

Returns:

The String with the author's name.

revision

public String revision()

Returns the revision number of this class as a string.

Specified by:

revision in class AbstractService

Returns:

The revision number of this class as a string.

dependencies

public String[] dependencies()

Returns the dependencies of this service as described in Service.

Specified by:

dependencies in interface Service

Overrides:

dependencies in class AbstractService

Returns:

The array of dependencies.

run

public void run()

This method represents the functionality of the refresh daemon.

Specified by:

run in interface Runnable

notifiedOf

public void notifiedOf(Object obj)

Description copied from interface: Listener

This method is called with the event that caused the notification.

Specified by:

notifiedOf in interface Listener

Parameters:

obj - The object describing the event.

filter

public ErrorCode filter(AgentContext agentContext)

Called from the information filter, which has to be installed within the incoming agent filter pipeline, whenever a new incomming agent has been detected.

Specified by:

filter in interface AgentFilter

Parameters:

agentContext - The agent context of the agent that is to be filtered.

Returns:

OK.

checkLANLocality

protected boolean checkLANLocality(Ticket ticket)
                            throws UnknownHostException

Checks the LAN locality of the destination URLs of the given ticket.

Parameters:

ticket - The ticket.

Returns:

true if every destination URL of the ticket lies in the current subnet; false otherwise.

Throws:

UnknownHostException - if the IP address of one of the ticket's URLs or the local Host could not be resolved.

proxyRefreshAllAgents

protected void proxyRefreshAllAgents()

Refreshes the location entries on the LSProxy of all agents which can be found on the local system through localLokupAll.

globalRefreshAllAgents

protected void globalRefreshAllAgents()

Refreshes the location entries on the LSServer of all agents, which can be found on the local system through localLookupAll.

register

protected void register(AgentContext ctx,
                        boolean init)

Registers this system as new location for the agent with the given agent context. This method considers the different error cases and handles them internally as good as possible. (It's assumed, that there already exists an older location entry for this entry and the agent contains the valid current cookie.)

Parameters:

ctx - The agent context.

init - true if a new entry should be initialized; true for an update request.

registerDelete

protected void registerDelete(AgentContext ctx)

Deletes the location entry for the agent with the given agent context. This method considers the different error cases and handles them internally as good as possible. (It's assumed that there exists a location entry for this agent.)

Parameters:

ctx - The agent context.

proxyInvalidate

protected void proxyInvalidate(AgentContext ctx)

Invalidates the proxy location entry for the agent with the given agent context. This method is called, if an agent migrates to another host outside the local LAN.

Parameters:

ctx - The agent context.

main

public static void main(String[] argv)
                 throws ArgsParserException,
                        ObjectExistsException

Initializes the LSClient from command line.

Parameters:

argv - The command line parameters.

Throws:

ArgsParserException

ObjectExistsException