TBoldSystemHandle¶

A TBoldSystemHandle component is used in the IDE of Delphi to represent an entire system of business elements, also known as an object-space.

Unit: BoldSystemHandle

Declaration¶

TBoldSystemHandle = class(TBoldAbstractSystemHandle)

Hierarchy¶

Description¶

In order to use it you must set SystemTypeInfoHandle to point at a TBoldSystemTypeInfoHandle which in turn must be connected to the TBoldModel for the system. If the system is to be persistent PersistenceHandle must also be connected. The active property decides whether the system is active or not. In most cases Active is left false at designtime, and AutoActivate is used instead.

Value
The value of the handle is the system owned by the handle. It will be nil if active is false.

Typing
The StaticBoldType is the type information for the entire system, which is held by SystemTypeInfoHandle.

Bold Events
TBoldSystemHandle is a subclass of TBoldSubscribableComponent, and can therefore by subscribed to using AddSmallSubscription. A TBoldSystemHandle can send the following events:

beDestroying: Sent when the handle is about to be destroyed.
beValueIdentityChanged: Sent whenever Active or TBoldAbstractSystemHandle.SystemTypeInfoHandle is changed.

Properties¶

Name	Summary	Notes
AutoActivate	Indicates if the system should be autmatically started when the application starts.
OnPreUpdate
PersistenceHandle	If a system is to be persistent it must be connected to a TBoldPersistenceHandle .
Persistent	This read-only property is true if PersistenceHandle is assigned.	read-only
RegionFactory		read-only

AutoActivate¶

property AutoActivate: Boolean;

If AutoActivate is True, Active will be set to True at runtime, otherwise Active will be False at start-up, and must be set to True programatically.

OnPreUpdate¶

property OnPreUpdate: TNotifyEvent;

PersistenceHandle¶

property PersistenceHandle: TBoldPersistenceHandle;

The persistence-handle defines all properties related to persistence. Persistence will only work properly if the PersistenceHandle is connected to the same model as the system-handle (or at least one containing an identical model).

Advanced information
The PersistenceHandle is stateless, so it is possible to connect multiple system-handles to the same persistence-handle.

Persistent¶

property Persistent: Boolean;

Persistent evaluates to True if the PersistenceHandle is assigned.

RegionFactory¶

property RegionFactory: TBoldRegionFactory;

Creates regions for the system, according to the region definitions supplied in the model.

Methods¶

Name	Summary	Notes
create	Creates an instance of TBoldSystemHandle	override
DefineProperties		protected, override
Destroy		override
GetActive		protected, override
GetSystem		protected, override
GetValue		protected, override
InstallOclDefinitionLookUp	Used by a repository to provide a Lookup-function for the OCL evaluator
Loaded		protected, override
ModelChanged		protected, override
RefersToComponent	Determine if there is a relationship to the component passed as parameter.	override
SetActive		protected, override
UpdateDatabase	Calling UpdateDatabase will update the database with all changes made in the objectspace belonging to the component.

create¶

constructor create(owner: TComponent); override; See also Ancestor Method

Use create to create an instance of TBoldSystemHandle.

Note that it needs some information to do its thing, most notably the SystemTypeInfoHandle must be set. To be able to persist the object space, the PersistenceHandle needs to be set.

DefineProperties¶

procedure DefineProperties(Filer: TFiler); override;

Destroy¶

destructor Destroy; override; See also Ancestor Method

Destroys the TBoldSystemHandle, freeing all resources, including the entire TBoldSystem if it is still active.

Bold events
Calling Destroy can result in the following events:

beDestroying: Sent when the handle is about to be destroyed, i.e. before any part of the destruction has been performed.

Don't call Destroy directly. Use Free instead.

GetActive¶

function GetActive: Boolean; override; See also Ancestor Method

GetSystem¶

function GetSystem: TBoldSystem; override; See also Ancestor Method

GetValue¶

function GetValue: TBoldElement; override; See also Ancestor Method

InstallOclDefinitionLookUp¶

procedure InstallOclDefinitionLookUp(const Value: TBoldLookUpOclDefinition);

This method is intended to be used by the TBoldOCLRepository to provide the OCL evaluator with a callback to perform a lookup of an expression in the repository

Loaded¶

procedure Loaded; override;

ModelChanged¶

procedure ModelChanged; override; See also Ancestor Method

RefersToComponent¶

function RefersToComponent(Component: TBoldSubscribableComponent): Boolean; override; See also Ancestor Method

RefersToComponent determins if there is a relationship between the TBoldSystemHandle and the component passed as parameter. It is used internally to avoid circular dependencies between components.

SetActive¶

procedure SetActive(Value: Boolean); override; See also Ancestor Method

UpdateDatabase¶

procedure UpdateDatabase;

It is equivalent to calling BoldSystem.UpdateDatabase.

If there is no system, most likely because the Active property is False, invoking this method will raise an exception.

Events¶

Name	Summary	Notes
OnOptimisticLockingFailed	Event that will be called if optimistic locking fails

OnOptimisticLockingFailed¶

TBoldOptimisticLockingFailedEvent = procedure(UpdateList, FailureList: TBoldObjectList; const FailureReason: String) of object;

If the application has optimistic locking activated, it might detect a conflict during an update. If this happens this event will be called with the objects that failed optimistic locking.

Generated from the Bold 4.0 help (Help/BfD.chm) by Tools/chm2mkdocs.py; member lists reflect Bold 4.0, see the source for members added since.