Collection

Classes
class	imtbase::CCachedObjectCollectionComp
class	imtbase::CCollectionInfo
class	imtbase::CCollectionObjectContext
class	imtbase::CFilterCollectionProxy
class	imtbase::CObjectCollection
class	imtbase::CObjectCollectionBase
class	imtbase::CObjectCollectionComp
class	imtbase::COptionsListAdapterComp
class	imtbase::COrderedObjectCollectionProxy
class	imtbase::CParamsManagerAdapterComp
class	imtbase::CStaticObjectCollection
class	imtbase::ICollectionDataController
class	imtbase::ICollectionFilter
class	imtbase::ICollectionInfo
class	imtbase::IComplexCollectionFilter
class	imtbase::IHierarchicalStructureIterator
class	imtbase::IObjectCollection
class	imtbase::IObjectCollectionEvent
class	imtbase::IObjectCollectionInfo
class	imtbase::IObjectCollectionIterator
class	imtbase::IObjectCollectionProvider
class	imtbase::IOrderedObjectCollection
class	imtbase::IReferenceCollection
class	imtbase::IRevisionController
class	imtdb::CSqlDatabaseCollectionStructureIterator
class	imtdb::CSqlDatabaseObjectCollectionIterator
class	imtgui::CDocumentCollectionViewDelegateComp
class	imtgui::CObjectCollectionViewDelegate
class	imtgui::CPluginStatusMonitorViewDelegateComp
class	imtgui::ICollectionViewDelegate
class	imtmongo::CMongoDatabaseObjectCollectionIterator
class	imtrepo::CFileCollectionComp
class	imtrepo::CFileObjectCollectionIterator
class	imtrepo::IFileObjectCollection
class	imtrepo::IRepositoryFileTransformation
class	imtrepo::IRepositoryFileTransformationStepsProvider
class	imtrepo::IRepositoryTransformationController

Detailed Description

Motivation

One of the most important aspects in the software development is the definition and implementation of the data layer. A general task here is the grouping of data, since we can assume that any software product must manage sets of entities. We call such sets of entities - Collection. The typical requirements for an entity collection are:

• Iterations over the collection
• Searching for entities based on one or more conditions
• Filtering of entities
• Reading and writing of entity data

The aim of the collection module is to standardize the working with object collections through a set of general interfaces and the associated implementations

Introduction

A collection is a container of items. We do not know anything about the structure or implementation detailes of the items in the container. The only thing we know about this container is that the items, that are located there, can be clearly identified (e.g. via a UUID). With regard to a collection, we therefore differentiate between two types of interfaces:

• Accessing to the items inside a collection
• Accessing to the information about the contents of a collection

The basic interface for access to information about a collection is imtbase::ICollectionInfo. This simple interface allows querying all existing IDs of the elements in the collection. If the IDs of elements are known, the properties (descriptions) of these elements can be accessed (via these IDs)

For a collection itself, we don't have a general interface. Instead, there are interfaces for certain types of collections, the most important one is - imtbase::IObjectCollection. This interface describes the collection of data objects, that is, objects that implement directly or indirectly the istd::IChangeable interface. "Concrete" collection interfaces can offer their specialized extensions to the imtbase::ICollectionInfo interface. There is a suitable imtbase::IObjectCollectionInfo interface for imtbase::IObjectCollection.

Object Collection

As already said, for the collection of data objects we provide the interface imtbase::IObjectCollection. This interface allows CRUD/L operations for a document container. There are following implementations of object/document collections:

• In-Memory collection (imtbase::CObjectCollection, imtbase::CObjectCollectionComp)
• File-based collection (imtrepo::CFileCollectionComp)
• SQL-Database collection (imtdb::CSqlDatabaseObjectCollectionComp)

An important aspect is the management of informations about objects containing in the collection. We differentiate between of followng kinds of such informations:

• Permanent/static information about a object/document in the collection such as Name or Description
• Meta-information related the object in the collection. For example Insertion Time, Last Modification Time. Important: these meta-informations are related to the Collection and not to the data object!
• Meta-information of the data object itself. Each object/document can have its own meta-informations