ABAP Keyword Documentation → ABAP - Reference → Declarative statemnts → Classes and Interfaces → Components in Classes and Interfaces → Methods → METHODS
METHODS - FOR EVENT
Other versions: 7.31 | 7.40 | 7.54
Syntax
METHODS meth [ABSTRACT|FINAL]
FOR EVENT evt OF {class|intf}
[IMPORTING p1 p2 ... [sender]].
Extras
1. ... IMPORTING p1 p2 ... [sender]
2. ... ABSTRACT
3. ... FINAL
Effect
This statement declares the instance method meth as an
event handler for the
event evt of class class or interface intf.
For class and intf, you can specify all classes
and interfaces which are visible in this position and which contain an event evt as a component that is visible here.
The visibility section of the event handler cannot be more general than the visibility section of the event. Otherwise properties of the method would be defined in a visibility section more restricted than the method itself.
If the event evt is an instance event, the event handler meth
can handle it for all objects whose classes match class or that are subclasses
of class or which implement the interface intf directly or by using a superclass. If the event is a
static event, the event
handler meth can handle it for the class class and its subclasses or for all classes that implement the interface intf.
Notes
-
To ensure that an event handler handles a triggered event, it must be registered with the statement
SET HANDLER.
In event handlers, no class-based exceptions can be declared usingRAISING. See Class-Based Exceptions in Event Handlers. -
When you declare event handlers for static events, remember that these events are generally triggered
in static methods as well. In a method of this type, the class in which the method is declared is always
the trigger, and not the subclass in which the method was called (or called using the name of the subclass).
Addition 1
... IMPORTING p1 p2 ... [sender]
Effect
The addition IMPORTING defines the input parameters of the event handler.
For p, you can specify only those names of formal parameters that are defined
as output parameters of the event by using the addition EXPORTING of the
statement EVENTS or
CLASS-EVENTS. This is done in the declaration of the event evt
in the class class or in the interface intf. The
additions TYPE or LIKE and OPTIONAL or DEFAULT are not possible. The
typing of the input parameters,
whether they are optional, and any replacement parameters are all defined in the declaration of the event. Not all output parameters of the event need to be specified.
If evt is an instance event, a formal parameter called sender
can be defined as an input parameter of an event handler, in addition to the explicitly defined output
parameters of the event. The formal parameter sender is an implicit output
parameter of every instance event. It is fully typed as a reference variable, which itself has the class
class or the interface intf as a static type,
as specified in the declaration of the event handler after EVENT evt OF.
If the event handler is called by an instance event, a reference to the triggering object is passed to it in sender.
Note
Each event handler determines the type of its formal parameter sender.
Example
The class picture contains an event handler handle_double_click
for the instance event picture_dblclick of the global class cl_gui_picture.
The event handler inherits two explicit output parameters of the event and the implicit parameter sender as input parameters.
CLASS picture DEFINITION.
PUBLIC SECTION.
METHODS handle_double_click
FOR EVENT picture_dblclick OF cl_gui_picture
IMPORTING mouse_pos_x mouse_pos_y sender.
ENDCLASS.
CLASS picture IMPLEMENTATION.
METHOD handle_double_click.
...
ENDMETHOD.
ENDCLASS.
Addition 2
... ABSTRACT
Addition 3
... FINAL
Effect
Using the additions ABSTRACT and FINAL, event handlers can either be made abstract or final just like
general methods.