orc.runtime.values
Class GroupCell

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

All Implemented Interfaces:

java.io.Serializable, Future

public class GroupCell
extends java.lang.Object
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

static GroupCell

ROOT

Constructor Summary

protected

GroupCell(TokenTracer.PullTrace pullTrace)

Method Summary

void	close()
GroupCell	createCell(TokenTracer.PullTrace pull) Groups are organized into a tree.
java.lang.Object	forceArg(Token t)
Callable	forceCall(Token t)
Transaction	getTransaction()
boolean	isAlive() Check if a group has been killed
boolean	isBound()
void	kill() Recursively kills all subgroups.
java.lang.Object	peekValue()
void	setRegion(Region region)
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 java.lang.Object

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

Field Detail

ROOT

public static final GroupCell ROOT

Constructor Detail

GroupCell

protected GroupCell(TokenTracer.PullTrace pullTrace)

Method Detail

createCell

public GroupCell createCell(TokenTracer.PullTrace pull)

Groups are organized into a tree. In this case a new subgroup is created and returned. When we add a new child cell, we can also remove any dead children so that their memory can be recycled.

Parameters:

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

Returns:

the new group

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

kill

public void kill()

Recursively kills all subgroups. After the children are killed, set children to null so that the memory used by the killed objects can be recycled.

isAlive

public boolean isAlive()

Check if a group has been killed

Returns:

true if the group has not been killed

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

close

public void close()

setRegion

public void setRegion(Region region)

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