CommandManager

java.lang.Object
- com.ibm.xtools.comparemerge.core.command.CommandManager

```
public class CommandManager
extends java.lang.Object
```
Responsible for managing the execution of commands. All repeatable actions (delegates and handlers) channel their command executions through a command manager. A command manager is always in one of four possible states, namely EXECUTING, IDLE, REDOING, or UNDOING. A command manager keeps track of the commands that have been executed, undone, and redone, and fires events to interested listeners whenever its state changes.

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

static class CommandManager.State
An enumeration of command manager states.

Nested Classes
Modifier and Type	Class and Description
`static class`	`CommandManager.State` An enumeration of command manager states.

Field Summary

Fields
Modifier and Type	Field and Description
`protected static int`	`DEFAULT_FLUSH_COUNT` The default flush count.
`protected static int`	`DEFAULT_FLUSH_THRESHOLD` The default flush threshold.
`protected static java.lang.String`	`EMPTY_STRING` The empty string.
`protected int`	`flushCount` The number of commands to flush from the undo stack.
`protected int`	`flushThreshold` The maximum size of the undo stack.
`static java.lang.String`	`REDO_LABEL_PREFIX` The prefix for Redo labels.
`protected static java.lang.String`	`SPACE` A string containing only a space character.
`static java.lang.String`	`UNDO_LABEL_PREFIX` The prefix for Undo labels.

Constructor Summary

Constructors
Constructor and Description

CommandManager()
Constructs a new command manager.

Constructors
Constructor and Description
`CommandManager()` Constructs a new command manager.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`protected void`	`addCommand(ICommand command)` Adds the specified command to the list of commands managed by this command manager.
`void`	`addCommandManagerChangeListener(ICommandManagerChangeListener listener)` Adds the specified listener to the list of command manager change listeners for this command manager.
`boolean`	`canRedo()` Retrieves a Boolean indicating whether a command can be redone.
`boolean`	`canUndo()` Retrieves a Boolean indicating whether a command can be undone.
`void`	`clear()` Clears this command manager by emptying its list of commands.
`protected void`	`clearRedoCommands()` Clears the redo stack.
`void`	`clearSilent()` Clears this command manager by emptying its list of commands WITHOUT broadcasting CommandManagerChangeEvent.
`protected void`	`clearUndoCommands()` Clears the undo stack.
`CommandResult`	`execute(ICommand command)` Executes the specified command.
`CommandResult`	`execute(ICommand command, org.eclipse.core.runtime.IProgressMonitor progressMonitor)` Executes the specified command.
`protected void`	`fireCommandManagerChange(CommandManagerChangeEvent event)` Notifies the listeners for this command manager that the specified event has occurred.
`protected void`	`flush()` Removes `flushCount` commands from the undo stack.
`void`	`flush(ICommand command)` Removes commands on the command stack down to, and including, the given command
`protected void`	`flushCommands(ICommand command)` Removes commands on the command stack down to, and including, the given command
`protected java.util.List`	`getCommands()` Retrieves the value of the `commands` instance variable.
`java.util.List`	`getCommandsAsList()` Retrieves a read-only list of the commands
`static CommandManager`	`getDefault()` Retrieves the default command manager.
`int`	`getFlushCount()` Retrieves the value of the `flushCount` instance variable.
`int`	`getFlushThreshold()` Retrieves the value of the `flushThreshold` instance variable.
`protected java.util.List`	`getListeners()` Retrieves the value of the `listeners` instance variable.
`java.lang.String`	`getRedoLabel()` Retrieves a label for the command that can be redone.
`CommandManager.State`	`getState()` Retrieves the value of the `state` instance variable.
`protected int`	`getUndoIndex()` Retrieves the value of the `undoIndex` instance variable.
`java.lang.String`	`getUndoLabel()` Retrieves a label for the command that can be undone.
`CommandResult`	`redo()` Redoes the command on the top of the redo stack.
`void`	`redo(ICommand command)` Redoes the every command up to, and including, the given command
`void`	`removeCommandManagerChangeListener(ICommandManagerChangeListener listener)` Removes the specified listener from the list of command manager change listeners for this command manager.
`void`	`setFlushCount(int flushCount)` Sets the `flushCount` instance variable to the specified value.
`void`	`setFlushThreshold(int flushThreshold)` Sets the `flushThreshold` instance variable to the specified value.
`protected void`	`setState(CommandManager.State state)` Sets the `state` instance variable to the specified value.
`protected void`	`setUndoIndex(int undoIndex)` Sets the `undoIndex` instance variable to the specified value.
`CommandResult`	`undo()` Undoes the command on the top of the undo stack.
`void`	`undo(ICommand command)` Undoes the every command down to, and including, the given command

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

- Field Detail
  - DEFAULT_FLUSH_THRESHOLD
```
protected static int DEFAULT_FLUSH_THRESHOLD
```
    The default flush threshold.
  - DEFAULT_FLUSH_COUNT
```
protected static int DEFAULT_FLUSH_COUNT
```
    The default flush count.
  - EMPTY_STRING
```
protected static final java.lang.String EMPTY_STRING
```
    The empty string.
    
    See Also:
    
    Constant Field Values
  - REDO_LABEL_PREFIX
```
public static final java.lang.String REDO_LABEL_PREFIX
```
    The prefix for Redo labels.
  - SPACE
```
protected static final java.lang.String SPACE
```
    A string containing only a space character.
    
    See Also:
    
    Constant Field Values
  - UNDO_LABEL_PREFIX
```
public static final java.lang.String UNDO_LABEL_PREFIX
```
    The prefix for Undo labels.
  - flushThreshold
```
protected int flushThreshold
```
    The maximum size of the undo stack.
  - flushCount
```
protected int flushCount
```
    The number of commands to flush from the undo stack.
- Constructor Detail
  - CommandManager
```
public CommandManager()
```
    Constructs a new command manager.
- Method Detail
  - getDefault
```
public static CommandManager getDefault()
```
    Retrieves the default command manager.
    
    Returns:
    
    The default command manager.
  - getCommands
```
protected final java.util.List getCommands()
```
    Retrieves the value of the commands instance variable.
    
    Returns:
    
    The value of the commands instance variable.
  - getCommandsAsList
```
public final java.util.List getCommandsAsList()
```
    Retrieves a read-only list of the commands
    
    Returns:
    
    a read-only list of the commands
  - getListeners
```
protected final java.util.List getListeners()
```
    Retrieves the value of the listeners instance variable.
    
    Returns:
    
    The value of the listeners instance variable.
  - getState
```
public final CommandManager.State getState()
```
    Retrieves the value of the state instance variable.
    
    Returns:
    
    The value of the state instance variable.
  - setState
```
protected final void setState(CommandManager.State state)
```
    Sets the state instance variable to the specified value.
    
    Parameters:
    
    state - The new value for the state instance variable.
  - getUndoIndex
```
protected final int getUndoIndex()
```
    Retrieves the value of the undoIndex instance variable.
    
    Returns:
    
    The value of the undoIndex instance variable.
  - setUndoIndex
```
protected final void setUndoIndex(int undoIndex)
```
    Sets the undoIndex instance variable to the specified value.
    
    Parameters:
    
    undoIndex - The new value for the undoIndex instance variable.
  - getFlushThreshold
```
public final int getFlushThreshold()
```
    Retrieves the value of the flushThreshold instance variable.
    
    Returns:
    
    The value of the flushThreshold instance variable.
  - setFlushThreshold
```
public final void setFlushThreshold(int flushThreshold)
```
    Sets the flushThreshold instance variable to the specified value.
    
    Parameters:
    
    flushThreshold - The new value for the flushThreshold instance variable.
  - getFlushCount
```
public final int getFlushCount()
```
    Retrieves the value of the flushCount instance variable.
    
    Returns:
    
    The value of the flushCount instance variable.
  - setFlushCount
```
public final void setFlushCount(int flushCount)
```
    Sets the flushCount instance variable to the specified value.
    
    Parameters:
    
    flushCount - The new value for the flushCount instance instance variable.
  - addCommandManagerChangeListener
```
public void addCommandManagerChangeListener(ICommandManagerChangeListener listener)
```
    Adds the specified listener to the list of command manager change listeners for this command manager.
    
    Parameters:
    
    listener - The listener to be added.
  - removeCommandManagerChangeListener
```
public void removeCommandManagerChangeListener(ICommandManagerChangeListener listener)
```
    Removes the specified listener from the list of command manager change listeners for this command manager.
    
    Parameters:
    
    listener - The listener to be removed.
  - fireCommandManagerChange
```
protected void fireCommandManagerChange(CommandManagerChangeEvent event)
```
    Notifies the listeners for this command manager that the specified event has occurred.
    
    Parameters:
    
    event - The command manager change event to be fired.
  - addCommand
```
protected void addCommand(ICommand command)
```
    Adds the specified command to the list of commands managed by this command manager.
    
    Parameters:
    
    command - The command to be added.
  - clearRedoCommands
```
protected void clearRedoCommands()
```
    Clears the redo stack.
  - clearUndoCommands
```
protected void clearUndoCommands()
```
    Clears the undo stack.
  - flushCommands
```
protected void flushCommands(ICommand command)
```
    Removes commands on the command stack down to, and including, the given command
    
    Parameters:
    
    command - the command to flush down to
  - clear
```
public final void clear()
```
    Clears this command manager by emptying its list of commands.
  - clearSilent
```
public final void clearSilent()
```
    Clears this command manager by emptying its list of commands WITHOUT broadcasting CommandManagerChangeEvent. Used to clean-up the undo/redo stack while disposing everything and notifications are not to be processed.
  - flush
```
public final void flush(ICommand command)
```
    Removes commands on the command stack down to, and including, the given command
    
    Parameters:
    
    command - the command to flush down to
  - flush
```
protected void flush()
```
    Removes flushCount commands from the undo stack.
  - canRedo
```
public boolean canRedo()
```
    Retrieves a Boolean indicating whether a command can be redone.
    
    Returns:
    
    true is a command can be redone; false otherwise.
  - canUndo
```
public boolean canUndo()
```
    Retrieves a Boolean indicating whether a command can be undone.
    
    Returns:
    
    true is a command can be undone; false otherwise.
  - getRedoLabel
```
public java.lang.String getRedoLabel()
```
    Retrieves a label for the command that can be redone.
    
    Returns:
    
    A label for the command that can be redone.
  - getUndoLabel
```
public java.lang.String getUndoLabel()
```
    Retrieves a label for the command that can be undone.
    
    Returns:
    
    A label for the command that can be undone.
  - execute
```
public CommandResult execute(ICommand command)
```
    Executes the specified command. A NullProgressMonitor is used so that commands which wish to report progress can do so without considering whether or not a progress monitor was supplied. The NullProgressMonitor implements the IProgressMonitor interface with an implementation that does nothing.
    
    Parameters:
    
    command - The command to be executed.
    
    Returns:
    
    The result of executing the command.
    
    Throws:
    
    java.lang.UnsupportedOperationException - If the command cannot be executed.
  - execute
```
public CommandResult execute(ICommand command,
                             org.eclipse.core.runtime.IProgressMonitor progressMonitor)
```
    Executes the specified command.
    The progressMonitor must not be null. To execute a command without a progress monitor, use execute(ICommand).
    
    Parameters:
    
    command - The command to be executed.
    
    progressMonitor - The object that monitors the progress of this command execution.
    
    Returns:
    
    The result of executing the command.
    
    Throws:
    
    java.lang.UnsupportedOperationException - If the command cannot be executed.
  - redo
```
public CommandResult redo()
```
    Redoes the command on the top of the redo stack.
    
    Returns:
    
    The result of redoing the command.
    
    Throws:
    
    java.lang.UnsupportedOperationException - If a command cannot be redone.
  - undo
```
public CommandResult undo()
```
    Undoes the command on the top of the undo stack.
    
    Returns:
    
    The result of undoing the command.
    
    Throws:
    
    java.lang.UnsupportedOperationException - If a command cannot be undone.
  - undo
```
public void undo(ICommand command)
```
    Undoes the every command down to, and including, the given command
    
    Parameters:
    
    command - the command to undo to
  - redo
```
public void redo(ICommand command)
```
    Redoes the every command up to, and including, the given command
    
    Parameters:
    
    command - the command to redo to

Class CommandManager

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

DEFAULT_FLUSH_THRESHOLD

DEFAULT_FLUSH_COUNT

EMPTY_STRING

REDO_LABEL_PREFIX

SPACE

UNDO_LABEL_PREFIX

flushThreshold

flushCount

Constructor Detail

CommandManager

Method Detail

getDefault

getCommands

getCommandsAsList

getListeners

getState

setState

getUndoIndex

setUndoIndex

getFlushThreshold

setFlushThreshold

getFlushCount

setFlushCount

addCommandManagerChangeListener

removeCommandManagerChangeListener

fireCommandManagerChange

addCommand

clearRedoCommands

clearUndoCommands

flushCommands

clear

clearSilent

flush

flush

canRedo

canUndo

getRedoLabel

getUndoLabel

execute

execute

redo

undo

undo

redo