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

Constructor Summary

GroupCell()

Method Summary

void	close()
GroupCell	createCell() Groups are organized into a tree.
Value	forceArg(Token t)
Callable	forceCall(Token t)
boolean	isAlive() Check if a group has been killed
void	setRegion(GroupRegion region)
void	setValue(Value value) This call defines the fundamental behavior of groups: When the value is bound, all subgroups are killed and all waiting tokens are activated.
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, toString, wait, wait, wait

Constructor Detail

GroupCell

public GroupCell()

Method Detail

createCell

public GroupCell createCell()

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.

Returns:

the new group

setValue

public void setValue(Value value)

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

Parameters:

value - the value for the group

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 Value forceArg(Token t)

Specified by:

forceArg in interface Future

forceCall

public Callable forceCall(Token t)

Specified by:

forceCall in interface Future

close

public void close()

setRegion

public void setRegion(GroupRegion region)