org.jacop.constraints.netflow

Class ArcCompanion

java.lang.Object

org.jacop.constraints.netflow.ArcCompanion

All Implemented Interfaces:

Comparable<ArcCompanion>, VarHandler

public final class ArcCompanion
extends Object
implements VarHandler, Comparable<ArcCompanion>

This class extends the definition of an arc by a lower bound on the capacity and connects the arc to variables that constrain it.

The ArcCompanion plays the role of the VarHandler for X- and W-variables. It also provides a hook for S-variables of any

Version:

4.9

Author:

Robin Steiger and Radoslaw Szymanek

Field Summary

Fields

Modifier and Type	Field and Description
Arc	arc The (forward) arc
int	arcID Identifier for this arc in the structure variable
int	flowOffset Current lower capacity of the arc
int	pruningScore The pruningScore
DomainStructure	structure The associated structure variable
IntVar	wVar The FDV for lower and upper cost
IntVar	xVar The FDV for lower and upper capacity

Constructor Summary

Constructors

Constructor and Description
ArcCompanion(Arc arc, int offset)

Method Summary

Modifier and Type	Method and Description
void	changeCapacity(int min, int max) Changes the lower and upper capacity of the arc in any way, performing the necessary changes to node balance and flow offset functions.
void	changeMaxCapacity(int max)
void	changeMinCapacity(int min)
int	compareTo(ArcCompanion that)
int	getPruningEvent(Var var) Retrieves the consistency pruning event of a handler variable that causes the handler to be reevaluated.
List<IntVar>	listVariables()
void	processEvent(IntVar variable, MutableNetwork network) Informs the handler that one of its variable has changed and asks the handler to update the state of the network accordingly.
void	restore(MutableNetwork network) Restores the capacity and weight of the arc after backtracking.
void	setFlow(int flow) Forces the flow to a given value (within capacity bounds).
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

arc

public final Arc arc

The (forward) arc

flowOffset

public int flowOffset

Current lower capacity of the arc

xVar

public IntVar xVar

The FDV for lower and upper capacity

wVar

public IntVar wVar

The FDV for lower and upper cost

structure

public DomainStructure structure

The associated structure variable

arcID

public int arcID

Identifier for this arc in the structure variable

pruningScore

public int pruningScore

The pruningScore

Constructor Detail

ArcCompanion

public ArcCompanion(Arc arc,
                    int offset)

Method Detail

toString

public String toString()

Overrides:

toString in class Object

changeCapacity

public void changeCapacity(int min,
                           int max)

Changes the lower and upper capacity of the arc in any way, performing the necessary changes to node balance and flow offset functions.

Parameters:

min - the new lower capacity

max - the new upper capacity

changeMinCapacity

public void changeMinCapacity(int min)

changeMaxCapacity

public void changeMaxCapacity(int max)

listVariables

public List<IntVar> listVariables()

Specified by:

listVariables in interface VarHandler

Returns:

the list of variables handled by this handler

processEvent

public void processEvent(IntVar variable,
                         MutableNetwork network)

Description copied from interface: VarHandler

Informs the handler that one of its variable has changed and asks the handler to update the state of the network accordingly.

Specified by:

processEvent in interface VarHandler

Parameters:

variable - the variable that changed

network - the network

restore

public void restore(MutableNetwork network)

Restores the capacity and weight of the arc after backtracking.

Parameters:

network - the network

setFlow

public void setFlow(int flow)

Forces the flow to a given value (within capacity bounds).

Parameters:

flow - the new flow value

getPruningEvent

public int getPruningEvent(Var var)

Description copied from interface: VarHandler

Retrieves the consistency pruning event of a handler variable that causes the handler to be reevaluated. For instance, X- and W-variables will listen to BOUND events while S-variables typically consider ANY events.

Specified by:

getPruningEvent in interface VarHandler

Parameters:

var - a handler variable

Returns:

the pruning event which causes reevaluation of the handler

compareTo

public int compareTo(ArcCompanion that)

Specified by:

compareTo in interface Comparable<ArcCompanion>