topic oops concepts in Application Development and Automation Discussions

oops concepts

Former Member — Wed, 26 Nov 2008 05:32:22 GMT

Hi All,

Could you please explain me the meaning of the following statement .I know the basic oops concepts but still i am confusing .

l_current_controller ?= wd_this->wd_get_api( ).

Thanks in advance.

Regards,

kumar.

Re: oops concepts

Former Member — Wed, 26 Nov 2008 05:36:05 GMT

Hi,

The method WD_GET_API which is contained in all generic controller interfaces allows the access to the corresponding runtime API.

Please check

http://help.sap.com/SAPHELP_NW04S/helpdata/EN/35/447741b0d6157de10000000a155106/content.htm

Edited by: Neenu Jose on Nov 26, 2008 6:39 AM

Re: oops concepts

Former Member — Wed, 26 Nov 2008 05:46:23 GMT

l_current_controller ?= wd_this->wd_get_api( )

It means

Is l_current_controller equal to the value returned by the method wd_get_api of class or object wd_this

Re: oops concepts

Former Member — Wed, 26 Nov 2008 05:51:01 GMT

thanks amit. What exactly the operator ' ?= ' means .

cheers,

kumar.

Re: oops concepts

Former Member — Wed, 26 Nov 2008 05:51:55 GMT

It checks weather the condition is true or false, just as in C++

Re: oops concepts

Former Member — Wed, 26 Nov 2008 06:26:57 GMT

amit please go through the following code .

Here it differs as per your clarification .

now i want to know what exactly the operator ?= doing here.

DATA: descriptor TYPE REF TO cl_abap_structdescr.

descriptor ?= cl_abap_structdescr=>describe_by_name( tablename ).

here after the above statement ' descriptor ' getting some values .

so let me know , is ?= assignment operator or conditional operator ?

cheers,

kumar.

Edited by: kumar on Nov 26, 2008 8:17 AM

Re: oops concepts

Former Member — Wed, 26 Nov 2008 07:25:54 GMT

Hi Kumar,

This is called WIDENING CASTING.

there is a much theory, so please go through the reliable documentaion.

Regards

ramchander Rao.K

Re: oops concepts

Former Member — Wed, 26 Nov 2008 07:56:11 GMT

hi,

DATA: descriptor TYPE REF TO cl_abap_structdescr.

descriptor ?= cl_abap_structdescr=>describe_by_name( tablename ).

?= is a "Widening Cast"

cl_abap_structdescr is a class which is a "Narrow Cast"

describe_by_name is a "Class Method"

tablename is a "Attribute of the Class method"

"descriptor ?=" means assigning the class method "describe_by_name" of the class "cl_abap_structdescr" i.e making the class "descriptor"

to point to the method "describe_by_name".