Shared Objects - Terms 

Area

Repository object for storing shared objects. An area is the template for area instance versions in the shared memory. Each area is assigned an area class with the same name and an area root class. Areas are created and managed using Transaction SHMA.

Area Handle

An instance of an area class. An area handle enables an ABAP program to access an area instance version in the shared memory and the shared objects that are stored there. An area handle is created by the static methods of its area class and is bound to an area instance version. Each bound area handle sets an area lock on the relevant area instance version.

Area Instance

Quantity of all area instance versions with the same area instance name. An area instance is a unique instance of an area, which is divided into versions of the area.

Area Instance Version

Instance of an area in the shared objects memory. Shared objects are stored in an area instance version as instances of shared memory-enabled classes. Each area instance version has at least one instance of the area root class. Area instance versions are created and accessed exclusively using area handles. Each area instance version has a name. Area instance versions with the same name make up an area instance.

Area Class

Final global class whose instances are used as area handles. The attributes of the instances of an area class represent the properties of an area. The static methods of an area class are used to access the area. All area classes are subclasses of CL_ABAP_MEMORY_AREA. When you create areas, area classes with the same name as generated as subclasses of CL_SHM_AREA. A specially predefined area class is CL_IMODE_AREA, whose instance is the area handle for the internal session of a program.

Area Lock

Write, read or update lock on an area instance version in the shared objects memory. Area locks are set when area handles are bound to area instance versions.

Area Root Class

A global shared memory-enabled class that has to be assigned to an area when it is defined. A non-empty area instance version contains at least one instance of the area root class (root object). The ROOT attribute of a corresponding area handle refers to this instance of the area root class. The root object contains references to the remaining shared objects of the area instance version.

Shared Memory

Memory area on an application server, which is accessed by all of this server’s ABAP programs. Either data clusters or shared objects can be stored in the shared memory.

Shared Memory-enabled Classes

Classes whose instances can be stored as shared objects in area instance versions of the shared memory. Shared memory-enabled classes are defined by the SHARED MEMORY ENABLED addition of the CLASSstatement. In particular, all area root classes have to be shared memory-enabled.

Shared Object

Object of a shared memory-enabled class or an anonymous data object that is stored in an area instance version of the shared memory. A shared object is created with the AREA HANDLE addition of the CREATE OBJECT or CREATE DATA statements. References to shared objects are possible in other shared objects with the same area instance version and during binding to the relevant area instance version using an area handle.

Shared Objects Memory

Part of the shared memory in which shared objects are stored in area instance versions.