Documentation

Converter interface definition.

System: The LHCb Offline System

Package: Converter

Purpose and functionality of data converters

The data converters are reposible to translate data from one representation into another. Concrete examples are e.g. converters creating transient objects representing parts of an event from the persistent (and disk based) representations. Converters will have to deal with the technology both representations are based on: in the upper example they have to know about the database internals as well as the structure of the transient representations. The converters know about the mechanism to retrieve persistent objects (ZEBRA, Objty, ) and only pass abstract instances of the converted objects, hence shielding the calling service from internals.

Data converters are meant to be light. This means there should not be all-in-one converters, which are able to convert the "world", but rather many converters. Each converter is then able to create a representation of a given type.

In order to function a converter must be able to

• Answer (when asked) which kind of representation the converter is able to create.
• Retrieve the source object from the source store.
• Create the requested representation using the information contained in the source object.
• Inform the registry entry of the created object that the object is now loaded.
• This registry entry is located in the data store which is supposed to manage the requested object.
• Register all leafs of the created object with the data store which is supposed to manage the requested object. Registering does not mean to create these representations, but rather to inform about the existence.

The interface should cover the entry points of concrete converter instances in order to serve conversion requests.

Dependencies:

• Experiment Kernel definitions: "Kernel/Kernel.h"
• Generic return code class: "Kernel/StatusCode.h"
• Generic interface definition: "Kernel/IInterface.h"

History:

+---------+----------------------------------------------+---------+
|    Date |                 Comment                      | Who     |
+---------+----------------------------------------------+---------+
| 3/11/98 | Initial version                              | M.Frank |
+---------+----------------------------------------------+---------+

This class has no child classes.

Author:

Markus Frank

Version:

1.0