abapGit/docs/collections/_development/serializers.md

title	order
Serializers	220

Overview

An abapGit Serializer is an ABAP class that supports create, read, update, and delete (CRUD) of objects of a given object type. In abapGit, read of an object is implemented in a 'serialize' method. Create and update are combined into a 'deserialize' method. There is a 'delete' method to remove an object from the system.

All object serializers must implement interface ZIF_ABAPGIT_OBJECT and be named ZCL_ABAPGIT_OBJECT_{type}, where {type} is the corresponding SAP object type (TADIR-OBJECT). As a description for the class, use {type} - {description of type} (for example, TABL - Table). It's recommended to use ZCL_ABAPGIT_OBJECTS_SUPER as a super class since it provides several convenient methods.

In general, only SAP Standard APIs for retriving and updating object information shall be used. If that is not possible, try using ZCL_ABAPGIT_OBJECTS_GENERIC which handles any logical transport object.

As code is stored in git, no usernames, timestamps, states (e.g. active/inactive) or other system specific information should be part of the serialized object files. Only the active, most recent and consistent version of an object shall be serialized.

If an inactive version of an object exists, the class shall indicate so in the is_active method. abapGit displays such objects with a yellow bolt icon in the repo view. However, the inactive version must be ignored by the serializer.

As a result, a repo shall only contain the definition of active objects. Therefore, the deserializer can assume that the repo contains a consistent object definition and shall create an active version of the object (or update and activate it).

Constructor

The constructor is implemented in the super class and take two parameters as input:

Parameter	Description
IS_ITEM	Contains object type, object name, SAP package, and state (active/inactive)
IV_LANGUAGE	Contains the language key for the main language of the repository

These parameters are stored in attributes MS_ITEM and MV_LANGUAGE respectively.

Interface

Serializers must implement all methods of interface ZIF_ABAPGIT_OBJECT:

Method	Description
SERIALIZE	Contains of all process steps to read the relevant object type specific information and serialize it (as one or more files)
DESERIALIZE	Contains of all process steps to create or update an object based on one or more files
DELETE	Contains of all process steps to delete an object based on one or more files
EXISTS	Returns whether a given object already exists in any state (i.e. return abap_true for inactive objects)
IS_LOCKED	Returns whether a given object is currently locked
IS_ACTIVE	Returns whether a given object exists in active state
CHANGED_BY	Returns the name of the use who last changed a given object (if undetermined, return c_user_unknown)
JUMP	Navigates to the corresponding object maintenance screen
GET_METADATA	Returns object specific metadata (see below)
GET_COMPARATOR	Triggered before deserialization to perform checks (for example, to warn the user that database tables are changed)
GET_DESERIALIZE_STEPS	Defines the deserialzation step or steps used to build the processing sequence (see below)

Example: DOMA.

Metadata

It is mandatory to provide the following metadata:

Attribute	Description
CLASS	Technical name used to identify the serializer within serialized XML files (format LCL_OBJECT_{type})
VERSION	Version number of the serializer (format v1.0.0)
DELETE_TADIR	Set to abap_true to force the removal of the TADIR entry after deletion of the object
DDIC	Set to abap_true if it is a DDIC object type (used for mass activation of DDIC objects)
LATE_DESER	Obsolete (to be removed)

It's recommended to fill CLASS and VERSION metadata using SUPER->GET_METADATA( ) and then changing settings as required.

Deserialization Step

It is mandatory to provide at least one deserialization step (see below).

Super Class

Serializers can take advantage of the following methods in ZCL_ABAPGIT_OBJECTS_SUPER:

Method	Description
GET_METADATA	Return default metadata for class and version
CORR_INSERT	Insert object into a transport (for transportable objects)
TADIR_INSERT	Insert object into TADIR
EXISTS_A_LOCK_ENTRY_FOR	Check if an enqueue lock exists
SET_DEFAULT_PACKAGE	Set SAP package for it can't be supplied via APIs for RS_CORR_INSERT
IS_ACTIVE	Method to check if an ABAP Workbench object or it's parts are active
DELETE_DDIC	Method to remove DDIC objects
CHECK_TIMESTAMP	Obsolete (to be removed)
JUMP_ADT	Obsolete (to be removed; use ZCL_ABAPGIT_OBJECTS->JUMP instead)
JUMP_SE11	Obsolete (to be removed; use ZCL_ABAPGIT_OBJECTS->JUMP instead)

In addition, there are some methods to handle documents associated with an object (transaction SE61, table DOKIL).

Method	Description
SERIALIZE_LONGTEXTS	Serialize document including I18N handling
DESERIALIZE_LONGTEXTS	Deserialize document including I18N handling
DELETE_LONGTEXTS	Delete document

Generic Class

If it's not possible to provide a native implementation for an object serializer, using generic class ZCL_ABAPGIT_OBJECTS_GENERIC is possible for logical transport objects (see table OBJH, object type L).

Example: IWMO.

Serialize Object

The serialize method shall produce one or several files containing the data that represents a given object. There are a few methods available to define files and attach data using ZIF_ABAPGIT_OUTPUT_XML (input parameter IO_XML).

Method	Description
ADD	Append a value, structure, or internal table to the output (using ID transformation to XML suppressing initial fields)
ADD_XML	Append an instance of an XML document to the output (IF_XML_ELEMENT)
SET_RAW	Set the output to an instance of an XML document (IF_XML_ELEMENT)
I18N_PARAMS	Get the settings for internationalization (see below)

Deserialize Object

The deserialize method shall read the file or files representing a given object and create such object in the system. If such object already exist, it shall be updated according to the definition in the file or files. There are a few methods available to process files using ZIF_ABAPGIT_INPUT_XML (input parameter IO_XML).

Method	Description
READ	Return a value, structure, or internal table from the input (using ID transformation from XML accepting data loss)
GET_RAW	Return the input as an instance of an XML document (IF_XML_ELEMENT)
GET_METADATA	Return the metadata used at time of serializing the object

In addition, the deserialize method must add or update the TADIR entry for the given object and insert the object into a transport request (for transportable packages). If the used SAP APIs are not performing these tasks, TADIR_INSERT( iv_package ) and CORR_INSERT( iv_package ) shall be called by the deserialize method.

Activate Object

After deserializing, an object (or dependent objects) might have to be activated. Add such objects to the activation queue using [ZCL_ABAPGIT_OBJECTS_ACTIVATION]:

Method	Description
ADD	Append a given object type and name to the queue (for example, INDX {table} for database indexes when deserializing tables)
ADD_ITEM	Append a given object to the queue (for example, use ms_item for activating the object itself)

The activation queue is built separately for each phase (see 'Deserialize Process' below).

Internationalization (I18N)

In general, the serializer class shall process texts of an object in all available languages i.e. the original language as well as any translations. It shall respect the "Serialize Main Language Only" setting of a repository and limit the texts to the language provided to the constructor (MV_LANGUAGE).

The recommended approach is to check io_xml->i18n_params( )-serialize_master_lang_only = abap_false and then serialize the additional translations in the XML (typically using I18N prefix). During deserialize the translation languages can then be retrieved and processed accordingly (

Example: TABL.

Testing

When adding new serializers, add at least one test repository to organization abapGit-tests which the name of the object type in capitals (for example, TABL. This test will be used by abapGit Continuous Integration.

Example (using SUSH):

1. Go to https://github.com/abapGit-tests/SUSH and create a fork
2. In your system (where you have the new SUSH class), start abapGit and create a new online repo for the URL of your fork (pick any local package like $SUSH).
3. Add one SUSH object to this package (like ZAG_UNIT_TEST)
4. Go back to abapGit and you should see the new object in the object list of the repo
5. Stage everything and commit
6. Go to your forked repo and create a pull request (at the top there's a section showing the delta to the original and a compare button which you can click to create the PR)

Processing Order and Dependencies

Serialize Process

abapGit determines which objects need to be serialized based on the SAP package assigned to a repository (including subpackages unless "Ignore subpackages" is selected in the repository settings). The list of objects is then sorted by package, object type, and object name.

If a sufficient number of work processes is available, abapGit will activate objects in parallel (unless "Disable Parallel Processing" is selected in the repository settings).

For details, see ZCL_ABAPGIT_SERIALIZE.

Deserialize Process

Objects are deserialized in three phases. After each phase all objects included in the phase will be activated.

Step	Description	Activation
DDIC	Used for DDIC objects which require early processing and activation before other object types	DDIC Mass Activation
ABAP	Used for non-DDIC objects (code or mostly anything else) which might depend on DDIC objects	Workbench Mass Activation
LATE	Used for objects that depend on other objects processed in the previous two phases	DDIC & Workbench Mass Activation

Within each phase, the sequence of objects is determined by abapGit based on known object type dependencies. For details, see ZCL_ABAPGIT_OBJECTS->PRIORITIZE_DESER.

Uninstall Process

During uninstallation of a repository, abapGit will determine the objects in the same fashion as the serialize process. The sequence of objects is determined by abapGit based on known object type dependencies. For details, see ZCL_ABAPGIT_DEPENDENCIES->RESOLVE.

Note: There are suggestions to refactor the logic to determine the processing order.