org.jacop.core

Class TimeStamp<T>

java.lang.Object

org.jacop.core.TimeStamp<T>

Type Parameters:

T - a class being stored at different time stamps.

All Implemented Interfaces:

Stateful

public class TimeStamp<T>
extends Object
implements Stateful

This class provides mutable variable functionality. The variable value depends on the store level. Each value is time stamped with different store level. This class lets you avoid recomputation every time a solver backtracks. It will simply use the value with older time stamp. It is appropriate for objects which do not share data across store levels. If you have objects which share data across store levels than you need to make your own implementation of mutable variable using MutableVar interface.

It will (it has to) store the same object at different levels as users of the timestamp may ask for the level at which the timestamp was recently updated.

Version:

4.9

Author:

Radoslaw Szymanek and Krzysztof Kuchcinski

Field Summary

Fields

Modifier and Type	Field and Description
int	pointer4Last
int[]	stamps
T[]	values

Constructor Summary

Constructors

Constructor and Description
TimeStamp(Store store, T input) The constructor.

Method Summary

Modifier and Type	Method and Description
void	ensureCapacity(int minCapacity) Specify least number of different values to be used by Timestamp.
T	previousValue()
void	removeLevel(int level) The function removes the level specified by the stamp.
int	stamp() It returns the value of the most recent stamp used within that timestamp.
String	toString()
void	update(T val) It updates the value of the timestamp with the provided value.
T	value() It returns the most recent value of the timestamp.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.jacop.api.Stateful

isStateful

Field Detail

pointer4Last

public int pointer4Last

stamps

public transient int[] stamps

values

public transient T[] values

Constructor Detail

TimeStamp

public TimeStamp(Store store,
                 T input)

The constructor.

Parameters:

store - the store where the timestamp is registered.

input - the value of the stamp to be stored.

Method Detail

ensureCapacity

public void ensureCapacity(int minCapacity)

Specify least number of different values to be used by Timestamp.

Parameters:

minCapacity - capacity that will be ensured

previousValue

public final T previousValue()

Returns:

the previous value according to the stamp.

removeLevel

public void removeLevel(int level)

The function removes the level specified by the stamp. It assumes that it removes all the levels from the most recent until the level (inclusive) specified by the parameter.

Specified by:

removeLevel in interface Stateful

Parameters:

level - the number of the level.

stamp

public final int stamp()

It returns the value of the most recent stamp used within that timestamp.

Returns:

the stamp value.

toString

public String toString()

Overrides:

toString in class Object

update

public void update(T val)

It updates the value of the timestamp with the provided value.

Parameters:

val - value to which the timestamp needs to be updated.

value

public final T value()

It returns the most recent value of the timestamp.

Returns:

the most recent value of the timestamp.