ptolemy.actor.sched

Class FixedPointReceiver

java.lang.Object

ptolemy.actor.AbstractReceiver

ptolemy.actor.sched.FixedPointReceiver

All Implemented Interfaces:

Receiver

public class FixedPointReceiver
extends AbstractReceiver

The receiver for use with FixedPointDirector or any of its subclasses. This receiver has capacity 1. The status of this receiver can be either known or unknown. If it is known, then it can be either present or absent. If it is present, then it has a token, which provides a value.

At first, an instance of this class has status unknown. The clear() method makes the status known and absent. The put() method makes the status known and present, and provides a value. The reset() method reverts the status to unknown. Once the status of a receiver becomes known, the value cannot be changed, nor can the status be changed from present to absent or vice versa. To change the value or the status, call reset() first. Normally, the reset() method is called only by the director and constructors.

The isKnown() method returns true if the receiver has status known. The hasRoom() method returns true if the receiver has status unknown. If the receiver has a known status, the hasToken() method returns true if the receiver contains a token. If the receiver has an unknown status, the hasToken() method will throw an InvalidStateException.

This class is based on the original SRReceiver, written by Paul Whitaker.

Since:

Ptolemy II 5.2

Version:

$Id$

Author:

Haiyang Zheng and Edward A. Lee

Pt.AcceptedRating:

Yellow (eal)

Pt.ProposedRating:

Green (hyzheng)

Field Summary

Fields

Modifier and Type	Field and Description
protected FixedPointDirector	_director The director of this receiver.
protected boolean	_known A flag indicating whether this receiver has status known.
protected Token	_token The token held.

Constructor Summary

Constructors

Constructor and Description
FixedPointReceiver() Construct an FixedPointReceiver with unknown status.
FixedPointReceiver(FixedPointDirector director) Construct an FixedPointReceiver with unknown status.

Method Summary

Modifier and Type	Method and Description
void	clear() Set the status of this receiver to be known and absent.
java.util.List<Token>	elementList() Return a list with the token currently in the receiver, or an empty list if there is no such token.
Token	get() Return the contained token.
boolean	hasRoom() Return true if the status of the receiver is unknown.
boolean	hasRoom(int numberOfTokens) If the argument is 1, return true if the status of the receiver is unknown.
boolean	hasToken() Return true if the receiver contains a token, and false otherwise.
boolean	hasToken(int numberOfTokens) If the argument is 1, return true if the receiver contains a token, and false otherwise.
boolean	isKnown() Return true if this receiver has status known, that is, this receiver either is either known to have a token or known to not to have a token.
void	put(Token token) If the specified token is non-null, then set the status of this receiver to known and present, and to contain the specified token.
void	reset() Reset the receiver by deleting any contained tokens and setting the status of this receiver to unknown, unless the containing port has no sources, in which case set to known and absent.
void	setContainer(IOPort port) Set the container.

Methods inherited from class ptolemy.actor.AbstractReceiver

getArray, getContainer, getCurrentTime, getModelTime, putArray, putArrayToAll, putToAll, toString

Methods inherited from class java.lang.Object

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

Field Detail

_director

protected FixedPointDirector _director

The director of this receiver.

_known

protected boolean _known

A flag indicating whether this receiver has status known.

_token

protected Token _token

The token held.

Constructor Detail

FixedPointReceiver

public FixedPointReceiver()

Construct an FixedPointReceiver with unknown status. This constructor does not need a director.

FixedPointReceiver

public FixedPointReceiver(FixedPointDirector director)

Construct an FixedPointReceiver with unknown status.

Parameters:

director - The director of this receiver.

Method Detail

clear

public void clear()
           throws IllegalActionException

Set the status of this receiver to be known and absent.

Specified by:

clear in interface Receiver

Overrides:

clear in class AbstractReceiver

Throws:

IllegalActionException - If this receiver is known and present.

elementList

public java.util.List<Token> elementList()

Return a list with the token currently in the receiver, or an empty list if there is no such token.

Specified by:

elementList in interface Receiver

Overrides:

elementList in class AbstractReceiver

Returns:

A list of instances of Token.

get

public Token get()
          throws NoTokenException

Return the contained token. If there is no token or the status of this receiver is unknown, throw an exception.

Specified by:

get in interface Receiver

Specified by:

get in class AbstractReceiver

Returns:

The token contained in the receiver.

Throws:

NoTokenException - If there is no token.

InvalidStateException - If the status is unknown.

hasRoom

public boolean hasRoom()

Return true if the status of the receiver is unknown.

Specified by:

hasRoom in interface Receiver

Specified by:

hasRoom in class AbstractReceiver

Returns:

True if the status of the receiver is unknown.

See Also:

isKnown()

hasRoom

public boolean hasRoom(int numberOfTokens)
                throws java.lang.IllegalArgumentException

If the argument is 1, return true if the status of the receiver is unknown. Otherwise, throw an exception. This receiver has capacity one.

Specified by:

hasRoom in interface Receiver

Specified by:

hasRoom in class AbstractReceiver

Parameters:

numberOfTokens - The number of tokens to put into the receiver.

Returns:

True if the receiver can accept a token.

Throws:

java.lang.IllegalArgumentException - If the argument is not positive.

See Also:

isKnown(), hasRoom()

hasToken

public boolean hasToken()

Return true if the receiver contains a token, and false otherwise. If the receiver has status unknown, this method will throw an exception.

Specified by:

hasToken in interface Receiver

Specified by:

hasToken in class AbstractReceiver

Returns:

True if this receiver contains a token.

Throws:

InvalidStateException - If the status is unknown.

hasToken

public boolean hasToken(int numberOfTokens)

If the argument is 1, return true if the receiver contains a token, and false otherwise. If the argument is larger than 1, return false (this receiver has capacity one). If the receiver has status unknown, throw an exception.

Specified by:

hasToken in interface Receiver

Specified by:

hasToken in class AbstractReceiver

Parameters:

numberOfTokens - The number of tokens.

Returns:

True if the argument is 1 and the receiver has a token.

Throws:

java.lang.IllegalArgumentException - If the argument is not positive.

InvalidStateException - If the status is unknown.

See Also:

hasToken()

isKnown

public boolean isKnown()

Return true if this receiver has status known, that is, this receiver either is either known to have a token or known to not to have a token.

Specified by:

isKnown in interface Receiver

Overrides:

isKnown in class AbstractReceiver

Returns:

True if this receiver has status known.

put

public void put(Token token)
         throws IllegalActionException

If the specified token is non-null, then set the status of this receiver to known and present, and to contain the specified token. If the receiver is already known and the value of the contained token is different from that of the new token, throw an exception. If the specified token is null, then set the status to be known and absent (by calling clear()).

Specified by:

put in interface Receiver

Specified by:

put in class AbstractReceiver

Parameters:

token - The token to be put into this receiver.

Throws:

java.lang.IllegalArgumentException - If the argument is null.

IllegalActionException - If the status is known and absent, or a token is present but not have the same value, or a token is present and cannot be compared to the specified token.

reset

public void reset()

Reset the receiver by deleting any contained tokens and setting the status of this receiver to unknown, unless the containing port has no sources, in which case set to known and absent. This is called by the , normally in its initialize() and postfire() methods.

Specified by:

reset in interface Receiver

Overrides:

reset in class AbstractReceiver

setContainer

public void setContainer(IOPort port)
                  throws IllegalActionException

Set the container. This overrides the base class so that if the container is being set to null, and if the director of this receiver is not null, this method removes the receiver from the list in that director.

Specified by:

setContainer in interface Receiver

Overrides:

setContainer in class AbstractReceiver

Parameters:

port - The container.

Throws:

IllegalActionException - If the container is not of an appropriate subclass of IOPort. Not thrown in this base class, but may be thrown in derived classes.

See Also:

AbstractReceiver.getContainer()