IlvChangeValueCommand Class Reference

A command class for storing simple attribute changes made to an object of the class IlvValueInterface. More...

#include <ilviews/base/command.h>

Inheritance diagram for IlvChangeValueCommand:

Public Member Functions
	IlvChangeValueCommand (IlvActionHistory *h=0, IlUInt n=0, const IlvValue *af=0, IlvValueInterface *o=0, const IlvValue *bf=0)
	Constructor. More...
virtual void	executeIt ()
	Executes the action (internal interface). More...
IlvValueInterface *	getObject () const
	Returns the object to which the command applies. More...
const IlvValue &	getValue (IlBoolean b, IlUInt i) const
	Returns the ith value stored in the command. More...
virtual void	snapshot (IlvValueInterface *o, const IlSymbol *s, IlBoolean before=IlTrue)
	Queries the specified value and records it. More...
virtual void	undoIt ()
	Implements the undo behavior. More...
IlString	userName () const
	Returns the name of the action in a readable form. More...
Public Member Functions inherited from IlvCommand
	IlvCommand (IlvActionHistory *h=0, IlvUndoabilityReason u=notImplemented, IlBoolean ps=IlFalse, IlBoolean r=IlTrue, IlBoolean p=IlFalse)
	Constructor. More...
IlBoolean	isPseudoCommand () const
	Is set to IlTrue if the command is a pseudocommand. More...
IlvUndoabilityReason	isUndoable () const
	Indicates whether the command can be undone, and tells why if it cannot. More...
virtual void	redo ()
	Redoes a command that was previously undone. More...
virtual void	undo ()
	Undoes a command. More...
Public Member Functions inherited from IlvAction
	IlvAction (IlvActionHistory *history=0, IlBoolean repeatable=IlTrue, IlBoolean persistent=IlFalse)
	Constructor. More...
	IlvAction (const IlvAction &action)
	Copy constructor used to repeat actions. More...
virtual	~IlvAction ()
	Destructor.
virtual IlvAction *	duplicate () const
	Must be implemented in subclasses for the action to be repeatable. More...
virtual IlString	errorMessage (IlUInt &severity) const
	Returns an error message. More...
virtual void	execute ()
	Executes the action. More...
IlvActionHistory *	getContext () const
	Returns the action history of the action or command. More...
IlBoolean	isCommand () const
	Indicates whether an action is an IlvCommand object. More...
IlBoolean	isDone () const
	Indicates whether the execute() method has already been called for this action. More...
IlBoolean	isRepeatable () const
	Indicates whether an action can be repeated. More...
virtual void	setContext (IlvActionHistory *history)
	Sets the execution context and the history of an action. More...
void	setDone (IlBoolean d=IlTrue)
	Specifies whether a command or action should be considered as being executed. More...

Additional Inherited Members
Public Attributes inherited from IlvAction
IlvActionFlags	_flags
	Action flags. Can be set directly by subclasses to change the status of the action.

Detailed Description

A command class for storing simple attribute changes made to an object of the class IlvValueInterface.

Library: views

Instances of IlvChangeValueCommand are used internally by IlvValueInterface::beforeChangeValues and IlvValueInterface::afterChangeValues to keep track of any value changes and store them in the current command history attached to a given value interface. If the flag recordValueChanges is IlTrue, all change value calls produce a change value object that will be added to the stack of executed commands. This process works by storing the value before and after it is modified.

See Also

IlvActionHistory, IlvCommand, IlvCommandHistory

Constructor & Destructor Documentation

IlvChangeValueCommand::IlvChangeValueCommand	(	IlvActionHistory *	h = 0,
		IlUInt	n = 0,
		const IlvValue *	af = 0,
		IlvValueInterface *	o = 0,
		const IlvValue *	bf = 0
	)

Constructor.

All these parameters are optional.

Parameters

h	The context to which the command applies.
n	The number of changed values.
af	The values after the command has been executed
o	The object to which the change of values is applied.
bf	The values before the command has been executed.

Member Function Documentation

virtual void IlvChangeValueCommand::executeIt ( )

virtual

Executes the action (internal interface).

This method must be implemented in subclasses to actually execute the action.

See Also

execute().

Implements IlvAction.

IlvValueInterface* IlvChangeValueCommand::getObject

(

)

const

Returns the object to which the command applies.

Returns

The object that the command applies to.

const IlvValue& IlvChangeValueCommand::getValue	(	IlBoolean	b,
		IlUInt	i
	)		const

Returns the ith value stored in the command.

Parameters

b	If set to IlTrue, the returned value is that of the object before the command is executed. Otherwise, it is the value of the object after the command is executed.
i	The index of the value in the array of stored values.

virtual void IlvChangeValueCommand::snapshot ( IlvValueInterface *  o, const IlSymbol *  s, IlBoolean  before = IlTrue  )

virtual

Queries the specified value and records it.

Parameters

o	The object to which the command applies.
s	The name of the value that is to be recorded.
before	If set to IlTrue, the command is considered as not executed. In this case, the snapshot is the state to which the undo method will revert the object. If set to IlFalse, the snapshot is the state to which the execute and redo methods should set the object.

virtual void IlvChangeValueCommand::undoIt ( )

virtual

Implements the undo behavior.

This method should be redefined in subclasses to cancel the executeIt method.

Reimplemented from IlvCommand.

IlString IlvChangeValueCommand::userName ( ) const

virtual

Returns the name of the action in a readable form.

By default, userName() searches the default message database of the display for an entry of the form '&<ActionClass>', and returns the string found.

Reimplemented from IlvAction.