Modeling.ObjectStoreCoordinator.ObjectStoreCoordinator

Package Modeling :: Module ObjectStoreCoordinator :: Class ObjectStoreCoordinator

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Class ObjectStoreCoordinator

ObjectStore --+
              |
             ObjectStoreCoordinator

ObjectStoreCoordinator API

Design Pattern: Chain of repsonsability

__TBD

By default only one 'ObjectStoreCoordinator' is created for an entire application ; however multiple coordinators might exist in an application (reasons will be details ine the future __TBD)

Implementation of interface 'ObjectStore'

With respect to implemented interface 'ObjectStoreInterface', the following methods make sense and are consequently overriden:

arrayFaultWithSourceGlobalID

faultForGlobalID

invalidateAllObjects

invalidateObjectsWithGlobalIDs

objectsForSourceGlobalID

objectsWithFetchSpecification

refaultObject

savesChangesInEditingContext

These methods' implementations simply forwards to the dedicated coordinator(s) the message ; determination of the coordinator(s) involved is done using either 'objectStoreForFetchSpecification', 'objectStoreForGlobalID' or 'objectStoreForObject'.

Implementation notes:

Remember that you should NOT access directly to instance variables, they are considered private (MT-safety)

Method Summary
	`__init__(self)`
	`addCooperatingObjectStore(self, aStore)` Adds a cooperating object store
	`arrayFaultWithSourceGlobalID(self, aGlobalID, aRelationshipName, anEditingContext)` See ObjectStore for details
	`cooperatingObjectStores(self)` Returns a copy of the list of registered cooperatingObjectStores
	`faultForGlobalID(self, aGlobalID, anEditingContext)` Forwards the message to the adequate CooperatingObjectStore, usually a DatabaseContext, and returns the result.
	`faultForRawRow(self, row, entityName, anEditingContext)` Forwards the message to the adequate CooperatingObjectStore, usually a DatabaseContext, and returns the result.
	`forwardUpdateForObject(self, anObject, aDictionaryOfChanges)` Called by a CooperatingObjectStore (usually a DatabaseContext) when it needs to notify that some changes were noticed that are not necessarily already noticed --this is the case, for example, when a toMany relationship, with no inverseRelationship declared in the model, has been changed.
	`initializeObject(self, anObject, aGlobalID, anEditingContext)` See ObjectStore for details
	`invalidateAllObjects(self)` See ObjectStore for details
	`invalidateObjectsWithGlobalIDs(self, globalIDs)` See ObjectStore
	`lock(self)` Acquire the lock for the ObjectStoreCoordinator.
	`objectsCountWithFetchSpecification(self, aFetchSpecification, anEditingContext)` Forwards the message to the appropriate CooperatingObjectStore, usually a DatabaseContext.
	`objectsForSourceGlobalID(self, aGlobalID, aRelationshipName, anEditingContext)` See ObjectStore for details
	`objectStoreForEntityName(self, entityName)` Iterates on objectStores and returns the first one who answers positively to message 'ownsEntityName'
	`objectStoreForFetchSpecification(self, aFetchSpecification)` Iterates on objectStores and returns the first one who answers positively to message 'handlesFetchSpecification'.
	`objectStoreForGlobalID(self, aGlobalID)` Iterates on objectStores and returns the first one who answers positively to message 'ownsGlobalID'
	`objectStoreForObject(self, anObject)` Iterates on objectStores and returns the first one who answers positively to message 'ownsObject'
	`objectsWithFetchSpecification(self, aFetchSpecification, anEditingContext)` See ObjectStore for details
	`ownsObject(self, anObject)` Tells whether the ObjectStore can handle the supplied object.
	`refaultObject(self, anObject, aGlobalID, anEditingContext)` See ObjectStore for details
	`removeCooperatingObjectStore(self, aStore)` Removes a cooperating object store
	`rootObjectStore(self)` Returns 'self', since an 'ObjectStoreCoordinator' object is designed to be the root of an ObjectStore hierarchy.
	`saveChangesInEditingContext(self, anEditingContext)` See ObjectStore for details
	`unlock(self)` Releases the lock for the ObjectStoreCoordinator.
Inherited from ObjectStore
	`editingContextDidForgetObjectWithGlobalID(self, aContext, aGlobalID)` See interfaces.ObjectStore for details
	`handlesObject(self, anObject)` An alias for ownsObject().
	`isObjectLockedWithGlobalID(self, aGlobalID, anEditingContext)` See interfaces.ObjectStore for details
	`lockObjectWithGlobalID(self, aGlobalID, anEditingContext)` See interfaces.ObjectStore for details
	`savesChangesInEditingContext(self, anEditingContext)` See interfaces.ObjectStore for details

Class Variable Summary
Inherited from ObjectStore
`tuple`	`__implements__` = `(<class Modeling.interfaces.ObjectStore...`

Method Details

addCooperatingObjectStore(self, aStore)

Adds a cooperating object store

Posts CooperatingObjectStoreWasAdded

arrayFaultWithSourceGlobalID(self, aGlobalID, aRelationshipName, anEditingContext)

See ObjectStore for details

Overrides:: Modeling.ObjectStore.ObjectStore.arrayFaultWithSourceGlobalID

cooperatingObjectStores(self)

Returns a copy of the list of registered cooperatingObjectStores

faultForGlobalID(self, aGlobalID, anEditingContext)

Forwards the message to the adequate CooperatingObjectStore, usually a DatabaseContext, and returns the result.

Overrides:: Modeling.ObjectStore.ObjectStore.faultForGlobalID

faultForRawRow(self, row, entityName, anEditingContext)

Forwards the message to the adequate CooperatingObjectStore, usually a DatabaseContext, and returns the result.

Overrides:: Modeling.ObjectStore.ObjectStore.faultForRawRow

forwardUpdateForObject(self, anObject, aDictionaryOfChanges)

Called by a CooperatingObjectStore (usually a DatabaseContext) when it needs to notify that some changes were noticed that are not necessarily already noticed --this is the case, for example, when a toMany relationship, with no inverseRelationship declared in the model, has been changed.

The ObjectStoreCoordinator simply locates the appropriate CooperatingObjectStore for 'anObject' then forwards the notification of changes to it.

Refer to DatabaseContext.recordUpdateForObject() and DatabaseOperation for a more complete discussion on this topic.

Paremeters:

anObject -- the object that needs to be notified of some changes.

aDictionary -- dictionary key/values corresponding to changes

See also: objectStoreForObject(),: CooperatingObjectStore.recordUpdateForObject()

initializeObject(self, anObject, aGlobalID, anEditingContext)

See ObjectStore for details

Overrides:: Modeling.ObjectStore.ObjectStore.initializeObject

invalidateAllObjects(self)

See ObjectStore for details

Overrides:: Modeling.ObjectStore.ObjectStore.invalidateAllObjects

invalidateObjectsWithGlobalIDs(self, globalIDs)

See ObjectStore

Overrides:: Modeling.ObjectStore.ObjectStore.invalidateObjectsWithGlobalIDs

lock(self)

Acquire the lock for the ObjectStoreCoordinator. Calls to 'lock()' should be balanced with the same number of 'unlock()' for the lock to be released.

You normally do not need to call this method directly.

objectsCountWithFetchSpecification(self, aFetchSpecification, anEditingContext)

Forwards the message to the appropriate CooperatingObjectStore, usually a DatabaseContext.

Returns the approximate number of objects that would be returned by objectsWithFetchSpecification() if called with the very same parameters.

About ``approximate'': the number returned is in fact the upper bound ; as the objects are not actually fetched against the database, it is not possible to determine whether some have already been deleted within anEditingContext (in which case objectsWithFetchSpecification() would not return them --see its documentation as well).

Parameters:

aFetchSpecification -- a FetchSpecification object describing the

objects to be fetched

anEditingContext -- the EditingContext in which the objects would be

fetched. This is in fact an optional argument: since no objects are fetched it is not really needed.

Overrides:: Modeling.ObjectStore.ObjectStore.objectsCountWithFetchSpecification

objectsForSourceGlobalID(self, aGlobalID, aRelationshipName, anEditingContext)

See ObjectStore for details

Overrides:: Modeling.ObjectStore.ObjectStore.objectsForSourceGlobalID

objectStoreForEntityName(self, entityName)

Iterates on objectStores and returns the first one who answers positively to message 'ownsEntityName'

Posts 'CooperatingObjectStoreNeeded' in case no store can be found at first glance, so that listeners get a chance to register an adequate 'CooperatingObjectStore' ; then the requested 'ObjectStore' is returned, or 'None' if it still cannot be found.

objectStoreForFetchSpecification(self, aFetchSpecification)

Iterates on objectStores and returns the first one who answers positively to message 'handlesFetchSpecification'.

objectStoreForGlobalID(self, aGlobalID)

Iterates on objectStores and returns the first one who answers positively to message 'ownsGlobalID'

objectStoreForObject(self, anObject)

Iterates on objectStores and returns the first one who answers positively to message 'ownsObject'

objectsWithFetchSpecification(self, aFetchSpecification, anEditingContext)

See ObjectStore for details

Overrides:: Modeling.ObjectStore.ObjectStore.objectsWithFetchSpecification

ownsObject(self, anObject)

Tells whether the ObjectStore can handle the supplied object. ObjectStoreCoordinator determines this by searching a matching CooperatingObjectStore for that object. If such a CooperatingObjectStore is found, returns true (1), else return false (0).

Note: this method directly triggers objectStoreForObject() --refer to its doc. for more info. on its side-effect.

refaultObject(self, anObject, aGlobalID, anEditingContext)

See ObjectStore for details

Overrides:: Modeling.ObjectStore.ObjectStore.refaultObject

removeCooperatingObjectStore(self, aStore)

Removes a cooperating object store

Posts CooperatingObjectStoreWasRemoved

rootObjectStore(self)

Returns 'self', since an 'ObjectStoreCoordinator' object is designed to be the root of an ObjectStore hierarchy.

See also: interface 'ObjectStore' for details

Overrides:: Modeling.ObjectStore.ObjectStore.rootObjectStore

saveChangesInEditingContext(self, anEditingContext)

See ObjectStore for details

unlock(self)

Releases the lock for the ObjectStoreCoordinator.