br.usp.ime.klava.segmentit.util
Class UndoRedo<T>

java.lang.Object
  br.usp.ime.klava.segmentit.util.UndoRedo<T>

Type Parameters:

T - type of the states

public class UndoRedo<T>
extends java.lang.Object

Stores states from which is possible to undo/redo actions.

Author:

Bruno Klava

Constructor Summary

UndoRedo(int capacity)
Creates a Undo/Redo structure that can store capacity states.

Method Summary

void	addNewState(T state) Adds a new state to the structure.
T	getCurrentState() Returns the current state.
boolean	isRedoAvailable() Returns if it is possible to go to a later state.
boolean	isUndoAvailable() Returns if it is possible to go to a previous state.
static void	main(java.lang.String[] args)
T	redo() Returns the state after the current state.
java.lang.String	toString()
T	undo() Returns the state before the current state.

Methods inherited from class java.lang.Object

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

Constructor Detail

UndoRedo

public UndoRedo(int capacity)

Creates a Undo/Redo structure that can store capacity states.

Parameters:

capacity - the maximum number of states stored

Method Detail

isUndoAvailable

public boolean isUndoAvailable()

Returns if it is possible to go to a previous state.

Returns:

if it is possible to go to a previous state

isRedoAvailable

public boolean isRedoAvailable()

Returns if it is possible to go to a later state.

Returns:

if it is possible to go to a later state

undo

public T undo()

Returns the state before the current state.

Returns:

the state before the current state, null if there isn't any previous accessible state.

redo

public T redo()

Returns the state after the current state.

Returns:

the state after the current state, null if there isn't any later accessible state.

addNewState

public void addNewState(T state)

Adds a new state to the structure.

Parameters:

state - the state to be added to the structure

getCurrentState

public T getCurrentState()

Returns the current state.

Returns:

the current state, null if there isn't any state available

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

main

public static void main(java.lang.String[] args)