java.lang.Object
- org.openstreetmap.josm.data.UndoRedoHandler

```
public final class UndoRedoHandler
extends java.lang.Object
```
This is the global undo/redo handler for all DataSets.
If you want to change a data set, you can use add(Command) to execute a command on it and make that command undoable.

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description
`static class`	`UndoRedoHandler.CommandAddedEvent`	Event fired after a command has been added to the command queue.
`static class`	`UndoRedoHandler.CommandQueueCleanedEvent`	Event fired after the command queue has been cleaned.
`(package private) static class`	`UndoRedoHandler.CommandQueueEvent`
`static interface`	`UndoRedoHandler.CommandQueueListener`	A simple listener that gets notified of command queue (undo/redo) size changes.
`static interface`	`UndoRedoHandler.CommandQueuePreciseListener`	A listener that gets notified of command queue (undo/redo) operations individually.
`static class`	`UndoRedoHandler.CommandRedoneEvent`	Event fired after a command has been redone.
`static class`	`UndoRedoHandler.CommandUndoneEvent`	Event fired after a command has been undone.
`private static class`	`UndoRedoHandler.InstanceHolder`

Field Summary

Fields
Modifier and Type	Field	Description
`private java.util.LinkedList<Command>`	`commands`	All commands that were made on the dataset
`private java.util.LinkedList<UndoRedoHandler.CommandQueueListener>`	`listenerCommands`
`private java.util.LinkedList<UndoRedoHandler.CommandQueuePreciseListener>`	`preciseListenerCommands`
`private java.util.LinkedList<Command>`	`redoCommands`	The stack for redoing commands

Constructor Summary

Constructors
Modifier Constructor Description

private UndoRedoHandler()
Constructs a new UndoRedoHandler.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`add(Command c)`	Executes the command and add it to the intern command queue.
`void`	`add(Command c, boolean execute)`	Executes the command only if wanted and add it to the intern command queue.
`boolean`	`addCommandQueueListener(UndoRedoHandler.CommandQueueListener l)`	Adds a command queue listener.
`boolean`	`addCommandQueuePreciseListener(UndoRedoHandler.CommandQueuePreciseListener l)`	Adds a precise command queue listener.
`void`	`addNoRedraw(Command c)`	Executes the command and add it to the intern command queue.
`void`	`addNoRedraw(Command c, boolean execute)`	Executes the command and add it to the intern command queue.
`void`	`afterAdd(java.util.List<? extends Command> cmds)`	Fires a commands change event after adding a list of commands.
`void`	`afterAdd(Command cmd)`	Fires a commands change event after adding a command.
`void`	`clean()`	Resets the undo/redo list.
`void`	`clean(DataSet dataSet)`	Resets all commands that affect the given dataset.
`private void`	`fireCommandsChanged()`	Fires a command change to all listeners.
`private void`	`fireEvent(UndoRedoHandler.CommandQueueEvent e)`
`static UndoRedoHandler`	`getInstance()`	Returns the unique instance.
`Command`	`getLastCommand()`	Gets the last command that was executed on the command stack.
`java.util.List<Command>`	`getRedoCommands()`	Returns all commands that were made and undone on the dataset, that can be redone.
`java.util.List<Command>`	`getUndoCommands()`	Returns all commands that were made on the dataset, that can be undone.
`boolean`	`hasRedoCommands()`	Determines if commands can be redone.
`boolean`	`hasUndoCommands()`	Determines if commands can be undone.
`void`	`redo()`	Redoes the last undoed command.
`void`	`redo(int num)`	Redoes multiple commands.
`void`	`removeCommandQueueListener(UndoRedoHandler.CommandQueueListener l)`	Removes a command queue listener.
`void`	`removeCommandQueuePreciseListener(UndoRedoHandler.CommandQueuePreciseListener l)`	Removes a precise command queue listener.
`void`	`undo()`	Undoes the last added command.
`void`	`undo(int num)`	Undoes multiple commands.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - commands
```
private final java.util.LinkedList<Command> commands
```
    All commands that were made on the dataset
    
    See Also:
    
    getLastCommand(), getUndoCommands()
  - redoCommands
```
private final java.util.LinkedList<Command> redoCommands
```
    The stack for redoing commands
    
    See Also:
    
    getRedoCommands()
  - listenerCommands
```
private final java.util.LinkedList<UndoRedoHandler.CommandQueueListener> listenerCommands
```
  - preciseListenerCommands
```
private final java.util.LinkedList<UndoRedoHandler.CommandQueuePreciseListener> preciseListenerCommands
```
- Constructor Detail
  - UndoRedoHandler
```
private UndoRedoHandler()
```
    Constructs a new UndoRedoHandler.
- Method Detail
  - getInstance
```
public static UndoRedoHandler getInstance()
```
    Returns the unique instance.
    
    Returns:
    
    the unique instance
    
    Since:
    
    14134
  - getUndoCommands
```
public java.util.List<Command> getUndoCommands()
```
    Returns all commands that were made on the dataset, that can be undone.
    
    Returns:
    
    all commands that were made on the dataset, that can be undone
    
    Since:
    
    14281, 16567 (signature)
  - getRedoCommands
```
public java.util.List<Command> getRedoCommands()
```
    Returns all commands that were made and undone on the dataset, that can be redone.
    
    Returns:
    
    all commands that were made and undone on the dataset, that can be redone.
    
    Since:
    
    14281, 16567 (signature)
  - getLastCommand
```
public Command getLastCommand()
```
    Gets the last command that was executed on the command stack.
    
    Returns:
    
    That command or null if there is no such command.
    
    Since:
    
    #12316
  - hasUndoCommands
```
public boolean hasUndoCommands()
```
    Determines if commands can be undone.
    
    Returns:
    
    true if at least a command can be undone
    
    Since:
    
    14281
  - hasRedoCommands
```
public boolean hasRedoCommands()
```
    Determines if commands can be redone.
    
    Returns:
    
    true if at least a command can be redone
    
    Since:
    
    14281
  - addNoRedraw
```
public void addNoRedraw(Command c)
```
    Executes the command and add it to the intern command queue.
    
    Parameters:
    
    c - The command to execute. Must not be null.
  - addNoRedraw
```
public void addNoRedraw(Command c,
                        boolean execute)
```
    Executes the command and add it to the intern command queue.
    
    Parameters:
    
    c - The command to execute. Must not be null.
    
    execute - true: Execute, else it is assumed that the command was already executed
    
    Since:
    
    14845
  - afterAdd
```
public void afterAdd(Command cmd)
```
    Fires a commands change event after adding a command.
    
    Parameters:
    
    cmd - command added
    
    Since:
    
    13729
  - afterAdd
```
public void afterAdd(java.util.List<? extends Command> cmds)
```
    Fires a commands change event after adding a list of commands.
    
    Parameters:
    
    cmds - commands added
    
    Since:
    
    14381
  - add
```
public void add(Command c,
                boolean execute)
```
    Executes the command only if wanted and add it to the intern command queue.
    
    Parameters:
    
    c - The command to execute. Must not be null.
    
    execute - true: Execute, else it is assumed that the command was already executed
  - add
```
public void add(Command c)
```
    Executes the command and add it to the intern command queue.
    
    Parameters:
    
    c - The command to execute. Must not be null.
  - undo
```
public void undo()
```
    Undoes the last added command.
  - undo
```
public void undo(int num)
```
    Undoes multiple commands.
    
    Parameters:
    
    num - The number of commands to undo
  - redo
```
public void redo()
```
    Redoes the last undoed command.
  - redo
```
public void redo(int num)
```
    Redoes multiple commands.
    
    Parameters:
    
    num - The number of commands to redo
  - fireCommandsChanged
```
private void fireCommandsChanged()
```
    Fires a command change to all listeners.
  - fireEvent
```
private void fireEvent(UndoRedoHandler.CommandQueueEvent e)
```
  - clean
```
public void clean()
```
    Resets the undo/redo list.
  - clean
```
public void clean(DataSet dataSet)
```
    Resets all commands that affect the given dataset.
    
    Parameters:
    
    dataSet - The data set that was affected.
    
    Since:
    
    12718
  - removeCommandQueueListener
```
public void removeCommandQueueListener(UndoRedoHandler.CommandQueueListener l)
```
    Removes a command queue listener.
    
    Parameters:
    
    l - The command queue listener to remove
  - addCommandQueueListener
```
public boolean addCommandQueueListener(UndoRedoHandler.CommandQueueListener l)
```
    Adds a command queue listener.
    
    Parameters:
    
    l - The command queue listener to add
    
    Returns:
    
    true if the listener has been added, false otherwise
  - removeCommandQueuePreciseListener
```
public void removeCommandQueuePreciseListener(UndoRedoHandler.CommandQueuePreciseListener l)
```
    Removes a precise command queue listener.
    
    Parameters:
    
    l - The precise command queue listener to remove
    
    Since:
    
    13729
  - addCommandQueuePreciseListener
```
public boolean addCommandQueuePreciseListener(UndoRedoHandler.CommandQueuePreciseListener l)
```
    Adds a precise command queue listener.
    
    Parameters:
    
    l - The precise command queue listener to add
    
    Returns:
    
    true if the listener has been added, false otherwise
    
    Since:
    
    13729

Class UndoRedoHandler

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

commands

redoCommands

listenerCommands

preciseListenerCommands

Constructor Detail

UndoRedoHandler

Method Detail

getInstance

getUndoCommands

getRedoCommands

getLastCommand

hasUndoCommands

hasRedoCommands

addNoRedraw

addNoRedraw

afterAdd

afterAdd

add

add

undo

undo

redo

redo

fireCommandsChanged

fireEvent

clean

clean

removeCommandQueueListener

addCommandQueueListener

removeCommandQueuePreciseListener

addCommandQueuePreciseListener