minicp.state

Class Trailer

java.lang.Object

minicp.state.Trailer

All Implemented Interfaces:

StateManager

public class Trailer
extends Object
implements StateManager

StateManager that will lazily store the state of state object at each saveState() call. Only the one that effectively change are stored and at most once between any to call to saveState(). This can be seen as an optimized version of Copier.

Constructor Summary

Constructors

Constructor and Description
Trailer()

Method Summary

Modifier and Type	Method and Description
int	getLevel() Returns the current level.
long	getMagic()
StateBool	makeStateBool(boolean initValue) Creates a Stateful boolean (restorable)
StateInt	makeStateInt(int initValue) Creates a Stateful integer (restorable)
StateMap	makeStateMap() Creates a Stateful map (restorable)
void	onRestore(Procedure listener) Add a listener that is notified each time the StateManager.restoreState() is called.
void	pushState(StateEntry entry)
void	restoreAllState() Restores the state as it was at level 0 (first saveState) The level is now -1.
void	restoreState() Restores state as it was at getLevel()-1 Decrease the level by 1
void	restoreStateUntil(int level) Restores the state up the the given level.
void	saveState() Stores the current state such that it can be recovered using restoreState() Increase the level by 1
void	withNewState(Procedure body) Higher-order function that preserves the state prior to calling body and restores it after.

Methods inherited from class java.lang.Object

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

Constructor Detail

Trailer

public Trailer()

Method Detail

onRestore

public void onRestore(Procedure listener)

Description copied from interface: StateManager

Add a listener that is notified each time the StateManager.restoreState() is called.

Specified by:

onRestore in interface StateManager

Parameters:

listener - the listener to be notified

getMagic

public long getMagic()

pushState

public void pushState(StateEntry entry)

getLevel

public int getLevel()

Description copied from interface: StateManager

Returns the current level. It is increased at each StateManager.saveState() and decreased at each StateManager.restoreState(). It is initially equal to -1.

Specified by:

getLevel in interface StateManager

Returns:

the level

saveState

public void saveState()

Description copied from interface: StateManager

Stores the current state such that it can be recovered using restoreState() Increase the level by 1

Specified by:

saveState in interface StateManager

restoreState

public void restoreState()

Description copied from interface: StateManager

Restores state as it was at getLevel()-1 Decrease the level by 1

Specified by:

restoreState in interface StateManager

withNewState

public void withNewState(Procedure body)

Description copied from interface: StateManager

Higher-order function that preserves the state prior to calling body and restores it after.

Specified by:

withNewState in interface StateManager

Parameters:

body - the first-order function to execute.

restoreAllState

public void restoreAllState()

Description copied from interface: StateManager

Restores the state as it was at level 0 (first saveState) The level is now -1. Notice that you'll probably want to saveState after this operation.

Specified by:

restoreAllState in interface StateManager

restoreStateUntil

public void restoreStateUntil(int level)

Description copied from interface: StateManager

Restores the state up the the given level.

Specified by:

restoreStateUntil in interface StateManager

Parameters:

level - the level, a non negative number between 0 and StateManager.getLevel()

makeStateInt

public StateInt makeStateInt(int initValue)

Description copied from interface: StateManager

Creates a Stateful integer (restorable)

Specified by:

makeStateInt in interface StateManager

Parameters:

initValue - the initial setValue

Returns:

a reference to the integer.

makeStateBool

public StateBool makeStateBool(boolean initValue)

Description copied from interface: StateManager

Creates a Stateful boolean (restorable)

Specified by:

makeStateBool in interface StateManager

Parameters:

initValue - the initial setValue

Returns:

a reference to the boolean.

makeStateMap

public StateMap makeStateMap()

Description copied from interface: StateManager

Creates a Stateful map (restorable)

Specified by:

makeStateMap in interface StateManager

Returns:

a reference to the map.