com.vaadin.addon.spreadsheet

Class SpreadsheetHistoryManager

java.lang.Object

com.vaadin.addon.spreadsheet.SpreadsheetHistoryManager

All Implemented Interfaces:

Serializable

public class SpreadsheetHistoryManager
extends Object
implements Serializable

SpreadsheetHistoryManager is an utility class of the Spreadsheet add-on. This class handles remembering any actions done in the Spreadsheet. The purpose is to allow the user to undo and redo any action.

Author:

Vaadin Ltd.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected LinkedList<Command>	commands All executed command in chronological order
protected int	historyIndex Current index within the history
protected Spreadsheet	spreadsheet Target Spreadsheet component

Constructor Summary

Constructors

Constructor and Description
SpreadsheetHistoryManager(Spreadsheet spreadsheet) Creates a new history manager for the given Spreadsheet.

Method Summary

Modifier and Type	Method and Description
void	addCommand(Command command) Adds a command to the end of the command history.
boolean	canRedo() Determines if redo is possible at the moment.
boolean	canUndo() Determines if undo is possible at the moment.
protected void	changeSelection(Command command) Applies the cell selection from the given Command.
void	clear() Clears the history.
protected void	discardAllAfter(int index) Clears all history after the given history index NOT including the command at the given index.
Command	getCommand(int historyIndex) Gets the Command at the given history index.
int	getHistoryIndex() Gets the current index within the Command history.
int	getHistorySize() Gets the current size of the Command history.
protected void	makeSureCorrectSheetActive(Command command) Ensures that the correct sheet is active, as recorded in the given Command.
void	redo() Does redo if possible.
void	setHistorySize(int historySize) Changes the history size.
void	undo() Does undo if possible.

Methods inherited from class java.lang.Object

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

Field Detail

historyIndex

protected int historyIndex

Current index within the history

commands

protected final LinkedList<Command> commands

All executed command in chronological order

spreadsheet

protected final Spreadsheet spreadsheet

Target Spreadsheet component

Constructor Detail

SpreadsheetHistoryManager

public SpreadsheetHistoryManager(Spreadsheet spreadsheet)

Creates a new history manager for the given Spreadsheet.

Parameters:

spreadsheet - Target spreadsheet

Method Detail

clear

public void clear()

Clears the history.

addCommand

public void addCommand(Command command)

Adds a command to the end of the command history. Discards commands after the current position (historyIndex) within the history.

Parameters:

command - Command to add as the latest command in history

getCommand

public Command getCommand(int historyIndex)

Gets the Command at the given history index.

Parameters:

historyIndex - Index of Command to get, 0-based

Returns:

The command at the index or IndexOutOfBoundsException

canRedo

public boolean canRedo()

Determines if redo is possible at the moment. In practice tells if there is at least one Command available after the current history index.

Returns:

true if redo() possible, false otherwise.

canUndo

public boolean canUndo()

Determines if undo is possible at the moment. In practice tells if there is at least one Command available before the current history index.

Returns:

true if undo() possible, false otherwise.

redo

public void redo()

Does redo if possible. Changes the active sheet to match the one the command belongs to and updates the selection if needed.

undo

public void undo()

Does undo if possible. Changes the active sheet to match the one that the command belongs to and updates the selection if needed.

setHistorySize

public void setHistorySize(int historySize)

Changes the history size. Discards possible commands that won't fit the size anymore.

Parameters:

historySize - New size for Command history

getHistorySize

public int getHistorySize()

Gets the current size of the Command history. The default size is 20 commands.

Returns:

Current size of history.

getHistoryIndex

public int getHistoryIndex()

Gets the current index within the Command history.

Returns:

Current history index, 0-based

makeSureCorrectSheetActive

protected void makeSureCorrectSheetActive(Command command)

Ensures that the correct sheet is active, as recorded in the given Command.

Parameters:

command - Command to fetch the sheet from

changeSelection

protected void changeSelection(Command command)

Applies the cell selection from the given Command.

Parameters:

command - Command to fetch the cell selection from.

discardAllAfter

protected void discardAllAfter(int index)

Clears all history after the given history index NOT including the command at the given index.

Parameters:

index - History index to start the clearing from.