{"id":1414,"date":"2015-05-31T15:59:16","date_gmt":"2015-05-31T14:59:16","guid":{"rendered":"http:\/\/oprsteny.cz\/?p=1414"},"modified":"2015-06-03T08:16:16","modified_gmt":"2015-06-03T07:16:16","slug":"abap-local-exception-classes","status":"publish","type":"post","link":"https:\/\/oprsteny.cz\/?p=1414","title":{"rendered":"ABAP – Local exception classes"},"content":{"rendered":"

\"SAP\"In this article I’d like to present a solution how to implement a global class<\/strong> where all internal<\/em> exceptions<\/em> (exceptions raised by private methods only\u00a0\u21d2 always catched within the class itself) will be handled with its local exception class<\/strong>. <\/p>\n

It is generally possible (and recommended) to use global exception classes but sometimes you\u00a0can find a local exception class be more practical (no DDIC entries, no heavy coding\/maintenance, …).<\/p>\n

I wanted a simple solution supporting WHERE-USED functionality for all messages defined in SE91 which can be generated in my program’s exceptions.<\/p>\n

\"Exception<\/a><\/p>\n

Sadly it is not possible to create a local exception class in a global class’s “local definitions” section AND use it in the global class method’s EXCEPTIONS section (by default<\/em>). This is because the class editor’s compiler does NOT see this local exception class as will be demonstrated in the following few steps.<\/p>\n

You maybe noticed the “by default”<\/em> note in the previous paragraph – this will be explained in the following paragraphs…<\/p>\n

Navigation to the global class’s local definitions & implementations:<\/p>\n

\"Navigation<\/a><\/p>\n

Here follows our local exception class definition which I entered in the “Local Class Definitions\/Types” section<\/p>\n

CLASS lcx_exception DEFINITION INHERITING FROM cx_static_check.\r\n  PUBLIC SECTION.\r\n    METHODS:\r\n      constructor,\r\n      get_text REDEFINITION.\r\n    CLASS-DATA:\r\n*     Statically accessible variable - the reason will be shown later\r\n      message TYPE bapiret2-message.\r\n  PRIVATE SECTION.\r\n    DATA:\r\n      mv_message TYPE bapiret2-message.\r\nENDCLASS.<\/pre>\n
I keep the local exception class implementation very simple:<\/p>\n
CLASS lcx_exception IMPLEMENTATION.\r\n  METHOD constructor.\r\n    super->constructor( ).\r\n*   Save the static variable to instance variable\r\n    me->mv_message = lcx_exception=>message.\r\n  ENDMETHOD.                   \r\n\r\n  METHOD get_text.\r\n*   Return message from the instance variable\r\n    result = me->mv_message.\r\n  ENDMETHOD.                   \r\nENDCLASS.<\/pre>\n
Now I’m trying to create new class method (called e.g. TEST_METHOD<\/em>), which would like to raise exceptions of type LCX_EXCEPTION – you can see the system reacts with popup message saying that such exception class is NOT KNOWN!!!<\/p>\n
…so the system offers to create a new GLOBAL exception class – but this is not what we wanted.<\/p>\n
\"Local<\/a><\/p>\n
Therefore the class method must<\/strong> raise a generic exception (e.g. CX_STATIC_CHECK) or a global exception from which your local exception class is inheriting from (by default<\/em>).<\/p>\n
\"Raising<\/a><\/p>\n
Did you notice the “by default<\/em>” note again in paragraph above?
\nIt is a “dark corner”<\/em> of the “Form-based”<\/em> class editor. This means that the form-based<\/em> editor can be very nice, intuitive, easy to navigate, … BUT…<\/p>\n
It is apparently missing some functionalities offered in the “Source code-based<\/em>” editor.<\/p>\n
Just try switching to the source-based<\/em> editor in SE24, put your local exception class (not the CX_STATIC_CHECK) in the RAISING section of the class-method and try to compile your code.<\/p>\n
\"Method<\/a><\/p>\n
WHAT, IT WORKS???!!!<\/p>\n
Now with equanimity you can switch back to the form-based editor and continue working as you were used to – the compiler won’t scream again unless you modify the EXCEPTIONS section of the class-method raising the local exception<\/em>.
\nBut in such case you can re-do this “source-editor trick”<\/em> againg of course.<\/p>\n
In the caller method (called e.g. RUN_TEST) you handle the exception occurrence like it was of you local exception class type.<\/p>\n
Note:<\/em> For testing purpose I created method RUN_TEST as Instance & Public<\/em> so I can execute it directly with F8.<\/p>\n
METHOD run_test.\r\n  DATA:\r\n    lr_my_exception     TYPE REF TO lcx_exception,\r\n    lr_static_exception TYPE REF TO cx_static_check,\r\n    lv_message          TYPE bapiret2-message.\r\n\r\n  TRY.\r\n    \r\n      me->test_method( ).\r\n    \r\n*   Catch my locally defined exception      \r\n    CATCH lcx_exception INTO lr_my_exception.\r\n      lv_message = lr_my_exception->get_text( ).\r\n      WRITE lv_message.\r\n      \r\n*   Catch any other exception of type CX_STATIC_CHECK \r\n    CATCH cx_static_check INTO lr_static_exception.\r\n      lv_message = lr_static_exception->get_text( ).\r\n      WRITE lv_message.\r\n  ENDTRY.\r\nENDMETHOD.<\/pre>\n
The code of the TEST_METHOD would be like this:<\/p>\n
METHOD test_method.\r\n  MESSAGE e001(ztest)\r\n    WITH 'ZCL_EXCEPTION_DEMO-TEST_METHOD'\r\n    INTO lcx_exception=>message.\r\n\r\n  RAISE EXCEPTION TYPE lcx_exception.\r\nENDMETHOD.<\/pre>\n
Important note<\/strong>:<\/em> In the above code please note the MESSAGE command. Thanks to this command the SAP system is able to find usage of the applied message with the WHERE-USED functionality from SE91<\/p>\n
\"Message<\/a><\/p>\n
For testing purposes I prepared a simple program that tests our solution:<\/p>\n
REPORT  zr_test_local_exceptions.\r\nDATA:\r\n  lr_demo TYPE REF TO zcl_exception_demo.\r\n\r\nSTART-OF-SELECTION.\r\n  CREATE OBJECT lr_demo.\r\n  lr_demo->run_test( ).<\/pre>\n
…and here comes the output:<\/p>\n
\"Exception<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"
In this article I’d like to present a solution how to implement a global class where all internal exceptions (exceptions raised by private methods only\u00a0\u21d2 always catched within the class itself) will be handled with its local exception class.<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"ABAP - Local exception classes http:\/\/wp.me\/p3nYbe-mO","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[16,15,9],"tags":[433,153],"class_list":["post-1414","post","type-post","status-publish","format-standard","hentry","category-abap","category-algorithms","category-development","tag-cx_static_check","tag-exception"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p3nYbe-mO","jetpack-related-posts":[],"_links":{"self":[{"href":"https:\/\/oprsteny.cz\/index.php?rest_route=\/wp\/v2\/posts\/1414","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/oprsteny.cz\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/oprsteny.cz\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/oprsteny.cz\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/oprsteny.cz\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1414"}],"version-history":[{"count":7,"href":"https:\/\/oprsteny.cz\/index.php?rest_route=\/wp\/v2\/posts\/1414\/revisions"}],"predecessor-version":[{"id":1432,"href":"https:\/\/oprsteny.cz\/index.php?rest_route=\/wp\/v2\/posts\/1414\/revisions\/1432"}],"wp:attachment":[{"href":"https:\/\/oprsteny.cz\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1414"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/oprsteny.cz\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1414"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/oprsteny.cz\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1414"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}