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Object class encapsulating the interpretation of an action of the user in a given context. More...
#include <ilviews/base/action.h>
Public Member Functions | |
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... | |
virtual void | executeIt ()=0 |
Executes the action (internal interface). 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... | |
virtual IlString | userName () const |
Returns the name of the action in a readable form. More... | |
Public Attributes | |
IlvActionFlags | _flags |
Action flags. Can be set directly by subclasses to change the status of the action. | |
Object class encapsulating the interpretation of an action of the user in a given context.
Library: views
The IlvAction
class implements actions performed by the user. An action is often the result of the interpretation of a series of events by an interactor. For example, a "move object" interactor intercepts events such as pressing, dragging, and releasing the mouse and transforms them to a "move object" action. Generally, interactors, such as the button interactor, generate callbacks instead of actions.
An action is the object equivalent of a callback that provides access to more features.
The IlvAction
class has an important subclass, IlvCommand
, which defines actions that cause the data structure to be modified, and that the user should be able to undo.
IlvActionHistory
, IlvCommand
, IlvCommandHistory
. IlvAction::IlvAction | ( | IlvActionHistory * | history = 0 , |
IlBoolean | repeatable = IlTrue , |
||
IlBoolean | persistent = IlFalse |
||
) |
Constructor.
history | The action history defining the context in which the action is performed. |
repeatable | Specifies whether the action can be repeated. |
persistent | Specifies whether the action is persistent. |
IlvAction::IlvAction | ( | const IlvAction & | action | ) |
Copy constructor used to repeat actions.
This constructor calls setDone(IlFalse)
so that the action can be repeated by copying it and calling execute()
on the copy.
action | The action to be copied. |
|
virtual |
Returns an error message.
This method should be redefined in action subclasses to generate error messages in case of failure.
severity | A value whose interpretation can be defined by the implementer. |
|
virtual |
Executes the action.
Checks the return value of isDone()
. If it is IlFalse
, execute()
calls executeIt()
and informs all the observers associated with the action class or the action history that an action has been performed.
|
pure virtual |
Executes the action (internal interface).
This method must be implemented in subclasses to actually execute the action.
execute()
. Implemented in IlvChangeValueCommand, and IlvMacroCommand.
IlvActionHistory* IlvAction::getContext | ( | ) | const |
Returns the action history of the action or command.
An IlvActionHistory
object is a context that stores the actions and commands that have been executed. It can be used to store additional information that can be used to simplify the execution of further actions.
For example, this context can store the arguments provided to past commands to facilitate the implementation of a smart repeat mechanism.
IlBoolean IlvAction::isCommand | ( | ) | const |
Indicates whether an action is an IlvCommand
object.
IlTrue
if this action is a command and IlFalse
otherwise. IlBoolean IlvAction::isDone | ( | ) | const |
Indicates whether the execute()
method has already been called for this action.
This flag is set by the execute()
method so that the same action is not executed twice.
It is especially useful for IlvCommand
objects because it indicates whether a command has been successfully executed (and therefore can be undone) or has been undone (and therefore can be redone).
IlBoolean IlvAction::isRepeatable | ( | ) | const |
Indicates whether an action can be repeated.
IlTrue
if this action can be repeated, and IlFalse
otherwise.
|
virtual |
Sets the execution context and the history of an action.
history | The history of this action. |
Specifies whether a command or action should be considered as being executed.
When an action or command is created and added to an IlvActionHistory
, the action history will check isDone()
to see if the command has been done.
If it is IlFalse
it will call the execute()
method.
You can call setDone(IlTrue)
to prevent the action history from calling execute
.
When a command is undone, setDone(IlFalse)
is called to indicate that the command can be executed again (IlvCommand::execute()
) or redone (IlvCommand::redo()
).
|
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 in IlvChangeValueCommand, and IlvMacroCommand.
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