ptolemy.domains.dt.kernel
Class DTReceiver

java.lang.Object
  ptolemy.actor.AbstractReceiver
      ptolemy.domains.sdf.kernel.SDFReceiver
          ptolemy.domains.dt.kernel.DTReceiver

All Implemented Interfaces:

Receiver

public class DTReceiver
extends SDFReceiver

A first-in, first-out (FIFO) queue receiver with variable capacity. Tokens are put into the receiver with the put() method, and removed from the receiver with the get() method. The token removed is the oldest one in the receiver. Time is incremented by a fixed amount delta time every time the get() method is called. Each receiver has its own value of delta time. We calculate delta time as "period / (rate * repetitions)" where:

• period is the execution time of the director per iteration
• rate is the rate of the port that holds this receiver
• repetitions is the firing count per iteration of the actor that holds this receiver

Since:

Ptolemy II 1.0

Version:

$Id: DTReceiver.java,v 1.63 2008/01/24 00:34:08 cxh Exp $

Author:

C. Fong

Accepted Rating:

Yellow (vogel)

Proposed Rating:

Yellow (chf)

Field Summary

Fields inherited from class ptolemy.domains.sdf.kernel.SDFReceiver

_waitingTokens, INFINITE_CAPACITY

Constructor Summary

DTReceiver()
Construct an empty receiver with no container.

DTReceiver(IOPort container)
Construct an empty receiver with the specified container.

DTReceiver(IOPort container, int size)
Construct an empty receiver with the specified container and size.

Method Summary

void	calculateDeltaTime() Calculate the constant time increment for this receiver.
void	determineEnds() Determine the source and destination ports that use this receiver in their communications.
Token	get() Remove the first token (the oldest one) from the receiver and return it.
double	getCurrentTime() Deprecated. As of Ptolemy II 4.1, replaced by getModelTime()
double	getDeltaTime() Return the time interval between tokens for this receiver.
Time	getModelTime() Return the local time associated with this receiver.
TypedIOPort	getSourcePort() Return the port that feeds this Receiver The port returned by this method is precalculated during the determineEnds() method call.
int	getTokenFlowRate() Return the token flow rate for this receiver In DT, the token flow rate has the value "rate * repetitions"; where 'rate' is the port rate and 'repetitions' is the firing count of the actor that contains this receiver.
boolean	hasToken() Return true if get() will succeed in returning a token.
void	put(Token token) Put a token to the receiver.
void	reset() Reset this receiver to its initial state, which includes calling clear() and resetting the current time to 0.0.

Methods inherited from class ptolemy.domains.sdf.kernel.SDFReceiver

clear, get, getArray, getCapacity, getHistoryCapacity, hasRoom, hasRoom, hasToken, historyElements, historySize, setCapacity, setHistoryCapacity, size

Methods inherited from class ptolemy.actor.AbstractReceiver

getContainer, isKnown, putArray, putArrayToAll, putToAll, setContainer, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

DTReceiver

public DTReceiver()

Construct an empty receiver with no container.

DTReceiver

public DTReceiver(IOPort container)
           throws IllegalActionException

Construct an empty receiver with the specified container.

Parameters:

container - The container of the receiver.

Throws:

IllegalActionException - If the container does not accept this receiver.

DTReceiver

public DTReceiver(IOPort container,
                  int size)
           throws IllegalActionException

Construct an empty receiver with the specified container and size.

Parameters:

container - The container of the receiver.

size - The size of the buffer for the receiver.

Throws:

IllegalActionException - If the container does not accept this receiver.

Method Detail

calculateDeltaTime

public void calculateDeltaTime()
                        throws IllegalActionException

Calculate the constant time increment for this receiver. This method should only be invoked by the DT Director.

Throws:

IllegalActionException - If there is an error in getting attribute information from the ports.

determineEnds

public void determineEnds()

Determine the source and destination ports that use this receiver in their communications. In DT, the source and destination ports are distinct for each receiver because "non-deterministic merge" type relations are not allowed.

get

public Token get()

Remove the first token (the oldest one) from the receiver and return it. If there is no token in the receiver, throw an exception. Increment the local time by deltaTime.

Specified by:

get in interface Receiver

Overrides:

get in class SDFReceiver

Returns:

The oldest token in the receiver.

getCurrentTime

public double getCurrentTime()

Deprecated. As of Ptolemy II 4.1, replaced by getModelTime()

Return the local time associated with this receiver.

Overrides:

getCurrentTime in class AbstractReceiver

Returns:

The local time associated with this receiver.

getDeltaTime

public double getDeltaTime()

Return the time interval between tokens for this receiver. Delta time is defined as "period / (token flow rate)"; where period is the director's period parameter and token flow rate is the number of tokens flowing through this receiver per iteration

Returns:

The time interval between tokens

getModelTime

public Time getModelTime()

Return the local time associated with this receiver.

Overrides:

getModelTime in class AbstractReceiver

Returns:

The local time associated with this receiver.

getSourcePort

public TypedIOPort getSourcePort()

Return the port that feeds this Receiver The port returned by this method is precalculated during the determineEnds() method call.

Returns:

The port that feeds this receiver.

getTokenFlowRate

public int getTokenFlowRate()

Return the token flow rate for this receiver In DT, the token flow rate has the value "rate * repetitions"; where 'rate' is the port rate and 'repetitions' is the firing count of the actor that contains this receiver.

Returns:

The token flow rate of this receiver

hasToken

public boolean hasToken()

Return true if get() will succeed in returning a token.

Specified by:

hasToken in interface Receiver

Overrides:

hasToken in class SDFReceiver

Returns:

A boolean indicating whether there is a token in this receiver.

put

public void put(Token token)

Put a token to the receiver. If the port feeding this receiver is null, report an internal error.

Specified by:

put in interface Receiver

Overrides:

put in class SDFReceiver

Parameters:

token - The token to be put to the receiver.

Throws:

InternalErrorException - If the source port is null.

reset

public void reset()
           throws IllegalActionException

Reset this receiver to its initial state, which includes calling clear() and resetting the current time to 0.0.

Specified by:

reset in interface Receiver

Overrides:

reset in class AbstractReceiver

Throws:

IllegalActionException - If there is no director.