org.jplot2d.env

Class UndoManager<E>

java.lang.Object

org.jplot2d.env.UndoManager<E>

public class UndoManager<E>
extends java.lang.Object

Maintains a queue of undo sets, a current set, and a redo sets.

Constructor Summary

Constructors

Constructor and Description
UndoManager() Construct a ChangeHistory with capacity 0.
UndoManager(int capacity) Construct a ChangeHistory with the given capacity.

Method Summary

Modifier and Type	Method and Description
void	add(E cs) Add the given change set as current, and push old change set into history.
boolean	canRedo() Returns true if redo is possible.
boolean	canUndo() Returns true if undo is possible.
E	current() Return the current change set.
int	getCapacity() Returns the capacity of undo stack.
int	getCSN() Returns the current CSN
int	getUndoSize() Returns the possible undo steps.
E	redo() Returns the next change set after the current change set.
void	setCapacity(int capacity) Sets the The capacity of undo stack.
E	undo() Move the change set before the current set to current, and return it.

Methods inherited from class java.lang.Object

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

Constructor Detail

UndoManager

public UndoManager()

Construct a ChangeHistory with capacity 0.

UndoManager

public UndoManager(int capacity)
            throws java.lang.IllegalArgumentException

Construct a ChangeHistory with the given capacity.

Parameters:

capacity - the capacity of the undo stack.

Throws:

java.lang.IllegalArgumentException - if the specified capacity is negative

Method Detail

getCapacity

public int getCapacity()

Returns the capacity of undo stack.

Returns:

the capacity of undo stack

setCapacity

public void setCapacity(int capacity)

Sets the The capacity of undo stack. The default capacity is 0.

Parameters:

capacity - the capacity of undo stack

getUndoSize

public int getUndoSize()

Returns the possible undo steps. The size dose not count the current change set.

Returns:

the possible undo steps

current

public E current()

Return the current change set.

Returns:

the current change set

getCSN

public int getCSN()

Returns the current CSN

Returns:

the current CSN

add

public void add(E cs)

Add the given change set as current, and push old change set into history.

Parameters:

cs - the change set

canUndo

public boolean canUndo()

Returns true if undo is possible.

Returns:

true if undo is possible

undo

public E undo()

Move the change set before the current set to current, and return it.

Returns:

the previous change set

canRedo

public boolean canRedo()

Returns true if redo is possible.

Returns:

true if redo is possible

redo

public E redo()

Returns the next change set after the current change set. Returns null if there is no next change set.

Returns:

the next change set