{"id":7215,"date":"2025-08-01T00:58:18","date_gmt":"2025-07-31T19:28:18","guid":{"rendered":"https:\/\/www.sapewmhelp.com\/?question=what-is-singleton-class-how-to-use-singleton-class-in-sap-abap"},"modified":"2025-08-01T00:58:18","modified_gmt":"2025-07-31T19:28:18","slug":"what-is-singleton-class-how-to-use-singleton-class-in-sap-abap","status":"publish","type":"question","link":"https:\/\/www.sapewmhelp.com\/?question=what-is-singleton-class-how-to-use-singleton-class-in-sap-abap","title":{"rendered":"What is Singleton Class ? how to use Singleton class in SAP ABAP ?"},"content":{"rendered":"

A\u00a0<\/span>Singleton class<\/strong>\u00a0<\/span>is a design pattern that restricts the instantiation of a class to\u00a0<\/span>one single object<\/strong>\u00a0<\/span>throughout the lifecycle of a program. This is useful when exactly one object is needed to coordinate actions across the system \u2014 such as logging, configuration management, or connection handling.<\/p>\n

Key Characteristics of Singleton Pattern:<\/h3>\n
    \n
  • Only one instance of the class exists.<\/li>\n
  • The class controls its own instantiation.<\/li>\n
  • A global access point is provided to access.<\/li>\n<\/ul>\n
    \n
    *&---------------------------------------------------------------------*<\/span>\r\n*&\u00a0Report\u00a0\u00a0ZREP_LCLCLASS<\/span>\r\n*&<\/span>\r\n*&---------------------------------------------------------------------*<\/span>\r\n*&<\/span>\r\n*&<\/span>\r\n*&---------------------------------------------------------------------*<\/span>\r\n\r\nREPORT\u00a0<\/span>zrep_lclclass.<\/span>\r\n\r\nCLASS\u00a0<\/span>lcl_class_singleton\u00a0DEFINITION\u00a0<\/span>CREATE\u00a0<\/span>PRIVATE<\/span>.<\/span>\r\n\u00a0\u00a0PUBLIC\u00a0<\/span>SECTION<\/span>.<\/span>\r\n\u00a0\u00a0\"\u00a0to\u00a0check\u00a0the\u00a0instance\u00a0is\u00a0created\u00a0or\u00a0not.<\/span>\r\n\u00a0\u00a0\u00a0\u00a0CLASS-METHODS<\/span>:\u00a0<\/span>m_factory\u00a0RETURNING\u00a0VALUE<\/span>(<\/span>r_instance)\u00a0<\/span>TYPE\u00a0<\/span>REF\u00a0<\/span>TO\u00a0<\/span>lcl_class_singleton.<\/span>\r\n\u00a0\u00a0\"\u00a0getter\u00a0and\u00a0setter\u00a0methods<\/span>\r\n\u00a0\u00a0\u00a0\u00a0METHODS\u00a0<\/span>:\u00a0<\/span>get_attribute\u00a0RETURNING\u00a0VALUE<\/span>(<\/span>r_attribute)\u00a0<\/span>TYPE\u00a0<\/span>i<\/span>,<\/span>\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0set_attribute\u00a0IMPORTING\u00a0<\/span>m_attribute\u00a0TYPE\u00a0<\/span>i<\/span>.<\/span>\r\n\r\n\u00a0\u00a0PRIVATE\u00a0<\/span>SECTION<\/span>.<\/span>\r\n*\u00a0\u00a0\u00a0\u00a0CLASS-DATA:\u00a0obj_instance\u00a0TYPE\u00a0REF\u00a0TO\u00a0lcl_class_singleton.<\/span>\r\n\u00a0\u00a0\u00a0\u00a0DATA\u00a0<\/span>gv_attribute\u00a0TYPE\u00a0<\/span>i<\/span>.<\/span>\r\nENDCLASS<\/span>.<\/span>\r\n\r\nclass\u00a0<\/span>lcl_class_singleton\u00a0IMPLEMENTATION<\/span>.<\/span>\r\n\u00a0\u00a0\u00a0\u00a0method\u00a0<\/span>m_factory.<\/span>\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0if\u00a0<\/span>r_instance\u00a0is\u00a0<\/span>not\u00a0<\/span>BOUND<\/span>.<\/span>\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0r_instance\u00a0=\u00a0<\/span>new\u00a0<\/span>lcl_class_singleton(\u00a0<\/span>)<\/span>.<\/span>\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0endif<\/span>.<\/span>\r\n\u00a0\u00a0\u00a0ENDMETHOD<\/span>.<\/span>\r\n\r\n\u00a0\u00a0\u00a0method\u00a0<\/span>get_attribute.<\/span>\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0r_Attribute\u00a0=\u00a0<\/span>gv_Attribute.<\/span>\r\n\u00a0\u00a0\u00a0ENDMETHOD<\/span>.<\/span>\r\n\r\n\u00a0\u00a0\u00a0method\u00a0<\/span>set_attribute.<\/span>\r\n\u00a0\u00a0\u00a0\u00a0\u00a0gv_Attribute\u00a0=\u00a0\u00a0<\/span>m_attribute.<\/span>\r\n\u00a0\u00a0\u00a0ENDMETHOD<\/span>.<\/span>\r\n\u00a0ENDCLASS<\/span>.<\/span>\r\n\r\n\u00a0START-OF-SELECTION<\/span>.<\/span>\r\n\u00a0\"\u00a0create\u00a0an\u00a0instance\u00a0of\u00a0class<\/span>\r\n\u00a0\u00a0\u00a0data<\/span>(<\/span>lo_obj)\u00a0<\/span>=\u00a0\u00a0<\/span>lcl_class_singleton=><\/span>m_factory(\u00a0<\/span>)<\/span>.<\/span>\r\n\u00a0\"\u00a0set\u00a0the\u00a0value\u00a0for\u00a0the\u00a0attribute.<\/span>\r\n\u00a0\u00a0\u00a0lo_obj-><\/span>set_attribute(\u00a0<\/span>10\u00a0<\/span>)<\/span>.<\/span>\r\n\r\n\u00a0\u00a0\u00a0\"\u00a0try\u00a0to\u00a0create\u00a0another\u00a0instace\u00a0of\u00a0the\u00a0class.<\/span>\r\n\u00a0\u00a0\u00a0\u00a0data<\/span>(<\/span>lo_obj2)\u00a0<\/span>=\u00a0<\/span>lcl_class_singleton=><\/span>m_factory(\u00a0<\/span>)<\/span>.<\/span>\r\n\u00a0\u00a0\u00a0\"\u00a0check\u00a0the\u00a0attribute\u00a0of\u00a0the\u00a0new\u00a0instance<\/span>\r\n\u00a0\u00a0\u00a0\"\u00a0it\u00a0should\u00a0be\u00a0same\u00a0as\u00a0go_obj\u00a0as\u00a0it\u00a0contains\u00a0a\u00a0static\u00a0attribute<\/span>\r\n\u00a0\u00a0\u00a0\"\u00a0get\u00a0the\u00a0data\u00a0and\u00a0print\u00a0it.<\/span>\r\n\u00a0\u00a0\u00a0write<\/span>:\u00a0<\/span>'First\u00a0object\u00a0attribute\u00a0value\u00a0<\/span>',\u00a0<\/span>lo_obj-><\/span>get_attribute(\u00a0<\/span>)<\/span>.<\/span>\r\n\u00a0\u00a0\u00a0write\u00a0<\/span>:<\/span>\/\u00a0'Second\u00a0object\u00a0attribute\u00a0value\u00a0<\/span>',\u00a0<\/span>lo_obj2-><\/span>get_attribute(\u00a0<\/span>)<\/span>.<\/span><\/span> \r\n<\/code><\/pre>\n
    Output:
    \n<\/p>\n<\/div>\n","protected":false},"author":3,"featured_media":0,"comment_status":"open","ping_status":"closed","template":"","question-category":[174],"question_tags":[178,171,195,168,177,211],"class_list":["post-7215","question","type-question","status-publish","hentry","question-category-ooabap","question_tags-abap","question_tags-class","question_tags-object","question_tags-ooabap","question_tags-sap","question_tags-singleton-class"],"_links":{"self":[{"href":"https:\/\/www.sapewmhelp.com\/index.php?rest_route=\/wp\/v2\/question\/7215","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.sapewmhelp.com\/index.php?rest_route=\/wp\/v2\/question"}],"about":[{"href":"https:\/\/www.sapewmhelp.com\/index.php?rest_route=\/wp\/v2\/types\/question"}],"author":[{"embeddable":true,"href":"https:\/\/www.sapewmhelp.com\/index.php?rest_route=\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/www.sapewmhelp.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=7215"}],"wp:attachment":[{"href":"https:\/\/www.sapewmhelp.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=7215"}],"wp:term":[{"taxonomy":"question-category","embeddable":true,"href":"https:\/\/www.sapewmhelp.com\/index.php?rest_route=%2Fwp%2Fv2%2Fquestion-category&post=7215"},{"taxonomy":"question_tags","embeddable":true,"href":"https:\/\/www.sapewmhelp.com\/index.php?rest_route=%2Fwp%2Fv2%2Fquestion_tags&post=7215"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}