= Anatomy of a !MeshBase =

[wiki:MeshBase MeshBases] are the containers for [wiki:MeshObject MeshObjects]. They have the following characteristics:

== General ==

 * Each MeshBase has a unique identifier, called the MeshBaseIdentifier.
 * Any MeshBase provides methods to find contained [wiki:MeshObject MeshObjects] by MeshObjectIdentifier and possibly by other criteria.
 * Any MeshBase has a reference to the ModelBase that contains the [wiki:Model] governing the content of the MeshBase.
 * Any MeshBase has an associated MeshObjectSetFactory object that knows how to construct [wiki:MeshObjectSet MeshObjectSets] appropriate for this MeshBase implementation.
 * Any MeshBase has an associated MeshObjectIdentifierFactory object that knows how to construct instances of MeshObjectIdentifier appropriate for [wiki:MeshObject MeshObjects] in this MeshBase.

== !HomeObject ==

 * Each MeshBase contains at least one MeshObject, called the MeshBase's HomeObject.
 * A MeshBase's HomeObject cannot be deleted; but it can participate in all other operations including [wiki:Blessing blessing], relationships etc.
 * The string form of the HomeObject's MeshObjectIdentifier is the same as the string form of the MeshBase's MeshBaseIdentifier.

== Modifying the content of the MeshBase ==

 * Life cycle operations on [wiki:MeshObject MeshObjects] are performed by means of an associated object called the MeshBaseLifecycleManager. There is exactly one MeshBaseLifecycleManager per MeshBase.
 * Read-only access to the content of a MeshBase does not require a [wiki:Transaction]. Listening to [wiki:Event Events] emitted by the MeshBase or a contained MeshObject does not require a [wiki:Transaction] either.
 * Any modifying operation to one or more [wiki:MeshObject MeshObjects] (e.g. [wiki:Property] update, relating, unrelating, blessing, unblessing, deleting etc.) in the MeshBase throws an exception unless it is performed within proper [wiki:Transaction] boundaries.

== !AccessManager ==

 * A MeshBase may have an associated AccessManager. The same AccessManager may be shared by several [wiki:MeshBase MeshBases].
 * The AccessManager encapsulates access control policies as they apply to the [wiki:MeshObject MeshObjects] in the MeshBase.

== Sweeper ==

 * A MeshBase may have an associated [wiki:Sweeper].
 * The [wiki:Sweeper]'s job is to periodically scan the content of the MeshBase and remove obsolete [wiki:MeshObject MeshObjects]. For example, a [wiki:Sweeper] may remove all [wiki:MeshObject MeshObjects] whose expiration time has passed. The [wiki:Sweeper] is in charge of its own policy.


See also:
 * [wiki:Docs/MeshObjectAnatomy Anatomy of a MeshObject]
 * [wiki:Docs/NetMeshBaseAnatomy Anatomy of a NetMeshBase]
 * MeshBase.