orc.runtime.values
Class GroupCell

java.lang.Object
  orc.runtime.Group
      orc.runtime.values.GroupCell

All Implemented Interfaces:

java.io.Serializable, Future

public final class GroupCell
extends Group
implements java.io.Serializable, Future

A value container that is also a group. Groups are essential to the evaluation of where clauses: all the tokens that arise from execution of a where definition are associated with the same group. Once a value is produced for the group, all these tokens are terminated.

Author:

wcook, dkitchin

See Also:

Serialized Form

Field Summary

Fields inherited from class orc.runtime.Group

alive

Constructor Summary

GroupCell(Group parent, TokenTracer.PullTrace pullTrace)

Method Summary

void	close() If a GroupRegion is closed, it closes the associated cell, even if that cell has not yet been bound.
java.lang.Object	forceArg(Token t)
Callable	forceCall(Token t)
Transaction	getTransaction()
boolean	isBound()
void	onKill() Override this.
java.lang.Object	peekValue()
void	setTransaction(Transaction trans)
void	setValue(Token token) This call defines the fundamental behavior of groups: When the value is bound, all subgroups are killed and all waiting tokens are activated.
java.lang.String	toString()
void	waitForValue(Token t) Add a token to the waiting queue of this group

Methods inherited from class orc.runtime.Group

add, isAlive, kill, remove

Methods inherited from class java.lang.Object

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

Constructor Detail

GroupCell

public GroupCell(Group parent,
                 TokenTracer.PullTrace pullTrace)

Parameters:

pullTrace - used to identify the group cell in traces (see TokenTracer.pull()).

Method Detail

setValue

public void setValue(Token token)

This call defines the fundamental behavior of groups: When the value is bound, all subgroups are killed and all waiting tokens are activated.

Parameters:

token - the token with the result value for the group

close

public void close()

If a GroupRegion is closed, it closes the associated cell, even if that cell has not yet been bound. This is necessary to ensure any tokens waiting on the cell are killed.

This is also called when a transaction is aborted.

onKill

public void onKill()

Description copied from class: Group

Override this.

Overrides:

onKill in class Group

waitForValue

public void waitForValue(Token t)

Add a token to the waiting queue of this group

Parameters:

t -

forceArg

public java.lang.Object forceArg(Token t)

Specified by:

forceArg in interface Future

forceCall

public Callable forceCall(Token t)
                   throws UncallableValueException

Specified by:

forceCall in interface Future

Throws:

UncallableValueException

getTransaction

public Transaction getTransaction()

setTransaction

public void setTransaction(Transaction trans)

peekValue

public java.lang.Object peekValue()

isBound

public boolean isBound()

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object