de.fhg.igd.atlas.core
Class LSProxy

java.lang.Object
  de.fhg.igd.semoa.service.AbstractService
      de.fhg.igd.semoa.net.AbstractServer
          de.fhg.igd.atlas.core.LSProxy

All Implemented Interfaces:

Runnable, Server, Service

public class LSProxy

extends AbstractServer

Provides a proxy server that will be used as gateway to Location Service Servers (LSServer) by Location Service Clients (LSClient) in the local LAN if existent. This Location Service Proxy (LSProxy) can be installed as potential proxy to improve the lookup speed and the fault tolerance in case of network breakdowns. The active proxy will be elected automatically among all existent potential proxys in the common LAN.

Following request are accepted as LSP messages from the local LAN:

• LSPLookup
• LSPRegisterPlain
• LSPRefresh
• LSPProxyInvalidate

Version:

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

Author:

Jan Peters

See Also:

LSProxyService, ProxyInfo

Nested Class Summary

Nested classes inherited from class de.fhg.igd.semoa.net.AbstractServer

AbstractServer.Job

Field Summary

private static String[]	DEPEND_ The dependencies to other objects in the global Environment.
private static Logger	log_ The Logger instance for this class
static int	MAX_CAPACITY The maximum capacity of this server.
static String	OPT_DESCR The ArgsParser option descriptor for the case that this class is initiated from command line.
static String	PROTOCOL The string identifier of the protocol spoken by this server.
protected ProxyInfo	proxyInfo_ The reference to an instance of , which is used to publish this component as electable LSProxy,
protected LSProxyServiceImpl	proxyService_ The reference to the LSProxyService interface.
static long	STORAGE_DB_TIMEOUT Timeout for entries of the internal storage database in milli seconds.

Fields inherited from class de.fhg.igd.semoa.net.AbstractServer

bad_, DEFAULT_CAPACITY, good_, thread_

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

REV_POSTFIX, REV_PREFIX

Fields inherited from interface de.fhg.igd.semoa.net.Server

BOUND_TO_PORT, ERROR, RUNNING, SHUTDOWN, UNDEFINED

Constructor Summary

protected

LSProxy(StorageDB storageDB, boolean verifyContactAddress) Creates an instance of this class and initializes the LSProxyService with the given parameters.

Method Summary

String	author() Returns the String with the author's name.
protected boolean	checkHostLocality() Checks if another LSProxy already runs on the same host with the initialized port.
protected boolean	checkLANLocality(Socket connection) Checks the LAN locality of the source of the given connection.
String[]	dependencies() Returns the dependencies of this service as described in Service.
protected void	handleConnection(Socket connection) Handles the given connection according to a simple request/response scheme.
protected LSPReply	handleRequest(LSPRequest request) Handles the given request and returns a corresponding reply.
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 LSProxy from command line.
String	protocol()
String	revision() Returns the revision number of this class as a string.
protected void	serverStateChanged(int state) Implementation of the server state hook, which is called by the servers run method.

Methods inherited from class de.fhg.igd.semoa.net.AbstractServer

bad, createJob, createServerSocket, exceptionInfo, getCapacity, getMaximumSize, getPort, getServerState, good, isEnabled, localURL, rebind, run, setCapacity, setEnabled, setMaximumSize, setPort, shutdown, signal, toString

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

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

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.

PROTOCOL

public static final String PROTOCOL

The string identifier of the protocol spoken by this server.

See Also:

Constant Field Values

MAX_CAPACITY

public static final int MAX_CAPACITY

The maximum capacity of this server.

See Also:

Constant Field Values

STORAGE_DB_TIMEOUT

public static long STORAGE_DB_TIMEOUT

Timeout for entries of the internal storage database in milli seconds.

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

proxyService_

protected LSProxyServiceImpl proxyService_

The reference to the LSProxyService interface.

proxyInfo_

protected ProxyInfo proxyInfo_

The reference to an instance of , which is used to publish this component as electable LSProxy,

Constructor Detail

LSProxy

protected LSProxy(StorageDB storageDB,
                  boolean verifyContactAddress)

Creates an instance of this class and initializes the LSProxyService with the given parameters. If storageDB is null, the MemoryDB is used as default database for the server. If filename is null, no server will be initialized.

Parameters:

storageDB - The storage database to use as part of the LSServer.

verifyContactAddress - If this flag is set, contact addresses to register are verified first (see LSProxyServiceImpl).

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

Overrides:

author in class AbstractServer

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.

protocol

public String protocol()

Specified by:

protocol in interface Server

Specified by:

protocol in class AbstractServer

Returns:

The string identifier of the protocol spoken by this server.

serverStateChanged

protected void serverStateChanged(int state)

Implementation of the server state hook, which is called by the servers run method. According to the current server state, the status of the local proxy is updated for the Vicinity election.

Overrides:

serverStateChanged in class AbstractServer

handleConnection

protected void handleConnection(Socket connection)

Handles the given connection according to a simple request/response scheme. This method is called if the server has accepted a new connection. In addition to the regular replies of corresponding requests, replies with the following states can be returned to sender in case of an error, which has been occured during request decoding:

• WRONG_VERSION
• REQUEST_TYPE_INVALID
• REQUEST_BODY_INVALID

Overrides:

handleConnection in class AbstractServer

Parameters:

connection - The socket connection that must be handled by this method.

checkHostLocality

protected boolean checkHostLocality()

Checks if another LSProxy already runs on the same host with the initialized port.

Returns:

true iff another LSProxy server is running locally, false otherwise.

checkLANLocality

protected boolean checkLANLocality(Socket connection)

Checks the LAN locality of the source of the given connection.

Returns:

true if the source of the connection lies in the current subnet; false otherwise.

handleRequest

protected LSPReply handleRequest(LSPRequest request)

Handles the given request and returns a corresponding reply. Following requests are allowed:

• LSPLookup
• LSPRegisterPlain
• LSPRefresh
• LSPProxyInvalidate

Parameters:

request - The request to be handled.

Returns:

The reply to the given request.

main

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

Initializes the LSProxy from command line.

Parameters:

argv - The command line parameters.

Throws:

ArgsParserException

ObjectExistsException