uwcse.location
Class LocationService

java.lang.Object
  |
  +--com.intel.research.rain.Service
        |
        +--uwcse.location.LocationService

All Implemented Interfaces:

MessageHandler

Direct Known Subclasses:

FuseSimDisplay, FusionClientService, FusionEval, FusionService, MeasurementLogger

public abstract class LocationService

extends Service

The abstract class to be extended by runnable Location Services.

Version:

$Revision: 1.20 $

Author:

Jeffrey Hightower

Nested Class Summary
class	LocationService.RediscoverServices           A task to rediscover a set of services.

 

Field Summary
protected static String	CONFIG_FILENAME
protected static String	MESSAGE_ELEMENT
protected static String	MESSAGE_EXTENSION
protected static String	RPC_ELEMENT
protected static String	RPC_EXCEPTION_ELEMENT
protected static String	RPC_EXTENSION
protected static String	RPC_RESULT_ELEMENT

 

Constructor Summary

LocationService()           Construct a new LocationService.

 

Method Summary
static void	addObject(Message m, String tagName, Object o)           This static utility method pickles the Object o into a Rain message under the given XML tagName.
LocationRpcResult	callLocationRpc(ServiceID id, LocationRpc rpc, long timeout)           A helper routine to execute a remote procedure call on the service with the given ServiceID and block until we receive result or an exception.
static long	correctedTimeMillis()           Get the current value of the system clock with a correction applied by the Ntp server.
static Object	getObject(Message m, String tagName)           This static helper method unpickles and extracts an Object from a Rain message under the given XML tagName.
static long	getSysclockError()           Get the number of milliseconds of error in our system clock versus the Ntp server.
protected  void	handleTerminalCommand(String cmd)           This routine is called to process command strings captured by runTerminalCommandLoop.
void	multicastLocationMsg(Collection serviceIDs, LocationMsg msg)           A helper routine to send a LocationMsg asynchronously to all the services in given Collection of ServiceIDs.
void	multicastLocationMsgs(Collection serviceIDs, Collection msgs)           A helper routine to send a Collection of LocationMsgs asynchronously to all the services in given Collection of ServiceIDs.
protected  void	processLocationMsg(ServiceID from, LocationMsg locationMsg)           Catch LocationMsgs which are not handled by any extending classes or multimethods.
protected  LocationRpcResult	processLocationRpc(ServiceID from, LocationRpc rpc)           Catch LocationRpc requests which are not handled by any extending classes or multimethods and throw an exception back to the sender.
void	runTerminalCommandLoop()           Run the terminal command reader to process location service terminal commands.
void	sendLocationMsg(ServiceID to, LocationMsg msg)           A helper routine to send a LocationMsg asynchronously to the given ServiceID.
void	sendLocationMsgs(ServiceID to, Collection msgs)           A helper routine to send a Collection of independent LocationMsgs to the given ServiceID.
void	setDescription(Element description)           Overridden to insert subclasses' descriptions inside the structured registration hierarchy before registering with discovery.
protected  void	withdraw()           Supplement the inherited behavior to shutdown the Ntp query timer when withdrawing from Rain.

 

Methods inherited from class com.intel.research.rain.Service

getDaemon, getDispatcher, getServiceID, process, receive, setDaemon

 

Methods inherited from class java.lang.Object

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

 

Field Detail

MESSAGE_EXTENSION

protected static final String MESSAGE_EXTENSION

MESSAGE_ELEMENT

protected static final String MESSAGE_ELEMENT

RPC_EXTENSION

protected static final String RPC_EXTENSION

RPC_ELEMENT

protected static final String RPC_ELEMENT

RPC_RESULT_ELEMENT

protected static final String RPC_RESULT_ELEMENT

RPC_EXCEPTION_ELEMENT

protected static final String RPC_EXCEPTION_ELEMENT

CONFIG_FILENAME

protected static final String CONFIG_FILENAME

LocationService

public LocationService()
                throws RainException,
                       LocationException

Construct a new LocationService. Ntp synchronization information is obtained if specified in the runtime definitions.

Throws:

RainException

LocationException

setDescription

public void setDescription(Element description)

Overridden to insert subclasses' descriptions inside the structured registration hierarchy before registering with discovery.

Overrides:

setDescription in class Service

processLocationMsg

protected void processLocationMsg(ServiceID from,
                                  LocationMsg locationMsg)

Catch LocationMsgs which are not handled by any extending classes or multimethods.

processLocationRpc

protected LocationRpcResult processLocationRpc(ServiceID from,
                                               LocationRpc rpc)
                                        throws Exception

Catch LocationRpc requests which are not handled by any extending classes or multimethods and throw an exception back to the sender.

Throws:

Exception

callLocationRpc

public final LocationRpcResult callLocationRpc(ServiceID id,
                                               LocationRpc rpc,
                                               long timeout)
                                        throws LocationRpcException

A helper routine to execute a remote procedure call on the service with the given ServiceID and block until we receive result or an exception. The ServiceID and reqMsg must not be null.

Parameters:

rpc - the remote procedure call to run

timeout - the timeout out in milliseconds to wait for a reply after which an exception will be thorwn

Returns:

the RPC result unless an exception is thrown on the remote service

Throws:

LocationRpcException - when an exception is thrown by the remote service. The cause is the exception thrown on the remote service.

See Also:

Throwable.getCause()

sendLocationMsg

public final void sendLocationMsg(ServiceID to,
                                  LocationMsg msg)
                           throws RainException

A helper routine to send a LocationMsg asynchronously to the given ServiceID. The service ID and msg must not be null.

Throws:

RainException

See Also:

multicastLocationMsg(Collection,LocationMsg), sendLocationMsgs(ServiceID,Collection), multicastLocationMsgs(Collection,Collection)

multicastLocationMsg

public final void multicastLocationMsg(Collection serviceIDs,
                                       LocationMsg msg)
                                throws RainException

A helper routine to send a LocationMsg asynchronously to all the services in given Collection of ServiceIDs. This method behaves similarly to calling sendLocationMsg() in a loop iterating over serviceIDs.

Throws:

RainException

See Also:

sendLocationMsg(ServiceID,LocationMsg), sendLocationMsgs(ServiceID,Collection), multicastLocationMsgs(Collection,Collection)

sendLocationMsgs

public final void sendLocationMsgs(ServiceID to,
                                   Collection msgs)
                            throws RainException

A helper routine to send a Collection of independent LocationMsgs to the given ServiceID. This method behaves similarly to calling sendLocationMsg() in a loop iterating over msgs. Msgs may be delivered to the remote service in arbitrary order.

Throws:

RainException

See Also:

sendLocationMsg(ServiceID,LocationMsg), multicastLocationMsg(Collection,LocationMsg), multicastLocationMsgs(Collection,Collection)

multicastLocationMsgs

public final void multicastLocationMsgs(Collection serviceIDs,
                                        Collection msgs)
                                 throws RainException

A helper routine to send a Collection of LocationMsgs asynchronously to all the services in given Collection of ServiceIDs. This method behaves similarly to calling sendLocationMsg() in a set of nested loops iterating over serviceIDs and msgs. Msgs may be delivered to each service in arbitrary and possibly different order.

Throws:

RainException

See Also:

sendLocationMsg(ServiceID,LocationMsg), multicastLocationMsg(Collection,LocationMsg), sendLocationMsgs(ServiceID,Collection)

addObject

public static void addObject(Message m,
                             String tagName,
                             Object o)

This static utility method pickles the Object o into a Rain message under the given XML tagName.

getObject

public static Object getObject(Message m,
                               String tagName)

This static helper method unpickles and extracts an Object from a Rain message under the given XML tagName.

Returns:

An Object extracted from the given tagName in the message or null if no such tagName or object is found or an error occurs.

runTerminalCommandLoop

public final void runTerminalCommandLoop()
                                  throws IOException

Run the terminal command reader to process location service terminal commands. This routine does not return until 'quit' (case insensitive) is read. This routine calls handleTerminalCommand(String) for all input except 'quit'

Throws:

IOException

See Also:

handleTerminalCommand(String)

correctedTimeMillis

public static final long correctedTimeMillis()

Get the current value of the system clock with a correction applied by the Ntp server.

See Also:

System.currentTimeMillis()

getSysclockError

public static final long getSysclockError()

Get the number of milliseconds of error in our system clock versus the Ntp server.

Returns:

the long offset in milliseconds of the system time versus the Ntp server's time

handleTerminalCommand

protected void handleTerminalCommand(String cmd)

This routine is called to process command strings captured by runTerminalCommandLoop. Classes extending LocationService may handle any command strings they wish except 'quit' (case insensitive) is a reserved command that causes the shell to exit.

See Also:

runTerminalCommandLoop()

withdraw

protected void withdraw()

Supplement the inherited behavior to shutdown the Ntp query timer when withdrawing from Rain.

Overrides:

withdraw in class Service