imod::CMultiModelObserverBase Class Reference

Basic implementation of a multiple model observer. More...

#include <CMultiModelObserverBase.h>

Inheritance diagram for imod::CMultiModelObserverBase:

Public Member Functions
	CMultiModelObserverBase ()
virtual	~CMultiModelObserverBase ()
int	GetModelCount () const
	Gets the number of connected models.
IModel *	GetObservedModel (int modelIndex) const
	Get access to connected model with the index index.
IModel *	GetModelPtr (int modelIndex) const
	Get access to connected model with the index index.
void	EnsureModelsDetached ()
	Ensure all attached models are detached.
void	SetObservedIds (const istd::IChangeable::ChangeSet &changeMask)
	Set list of ID's beeing observed.
virtual bool	IsModelAttached (const IModel *modelPtr) const override
	Checks if the specified model is currently attached to this observer.
virtual bool	OnModelAttached (IModel *modelPtr, istd::IChangeable::ChangeSet &changeMask) override
	Callback invoked when an observable model is about to be attached to this observer.
virtual bool	OnModelDetached (IModel *modelPtr) override
	Callback invoked when an observable model is about to be detached from this observer.
virtual void	BeforeUpdate (IModel *modelPtr) override
	Callback invoked before an update of the observer's content occurs.
virtual void	AfterUpdate (IModel *modelPtr, const istd::IChangeable::ChangeSet &changeSet) override
	Callback invoked after an update of the observer's content occurs.
Public Member Functions inherited from istd::IPolymorphic
virtual	~IPolymorphic ()

Protected Member Functions
virtual void	OnUpdate (IModel *modelPtr, const istd::IChangeable::ChangeSet &changeSet)
	Called on update of observed model.

Detailed Description

Basic implementation of a multiple model observer.

Definition at line 23 of file CMultiModelObserverBase.h.

Constructor & Destructor Documentation

CMultiModelObserverBase()

imod::CMultiModelObserverBase::CMultiModelObserverBase

(

)

~CMultiModelObserverBase()

virtual imod::CMultiModelObserverBase::~CMultiModelObserverBase ( )

virtual

Member Function Documentation

AfterUpdate()

virtual void imod::CMultiModelObserverBase::AfterUpdate ( IModel *  modelPtr, const istd::IChangeable::ChangeSet &  changeSet  )

overridevirtual

Callback invoked after an update of the observer's content occurs.

This is the primary notification method where observers react to model changes. It's called after the model has finished updating its state. The implementation should examine the changeSet to determine what changed and update accordingly.

Parameters

modelPtr	Pointer to the model that has changed
changeSet	Contains information about what changed in the model. Use changeSet.Contains(changeId) to check for specific changes. The changeSet respects the mask specified in OnModelAttached().

Note

This is typically where you update your GUI, recalculate derived values, or trigger other dependent operations.

Keep this method fast - it's called frequently and may block the UI thread.

Use the changeSet to perform incremental updates rather than refreshing everything.

virtual void AfterUpdate(IModel* modelPtr, 
                        const istd::IChangeable::ChangeSet& changeSet)
{
       CMyModel* model = dynamic_cast<CMyModel*>(modelPtr);
       if (!model) return;
       
       // Selective update based on what changed
       if (changeSet.Contains(CMyModel::CF_NAME_CHANGED)) {
              m_nameLabel->setText(model->GetName());
       }
       if (changeSet.Contains(CMyModel::CF_VALUE_CHANGED)) {
              m_valueSpinBox->setValue(model->GetValue());
              RecalculateDependentValues();
       }
       
       // Re-enable signals if blocked in BeforeUpdate
       if (m_widget) {
              m_widget->blockSignals(false);
       }
}

See also

BeforeUpdate(), OnModelAttached()

Implements imod::IObserver.

BeforeUpdate()

virtual void imod::CMultiModelObserverBase::BeforeUpdate ( IModel *  modelPtr )

overridevirtual

Callback invoked before an update of the observer's content occurs.

This method is called at the start of a model update cycle, before any data actually changes. It allows the observer to prepare for the update, such as saving current state for comparison or disabling UI updates temporarily.

Parameters

modelPtr

Pointer to the model that is about to change

Warning

In some error cases, this method may be called without a subsequent AfterUpdate() call. Don't rely on AfterUpdate() always being called.

Note

This method is optional to implement - if you don't need preparation logic, just provide an empty implementation.

virtual void BeforeUpdate(IModel* modelPtr)
{
       // Example: Block signals to prevent multiple GUI updates
       if (m_widget) {
              m_widget->blockSignals(true);
       }
       
       // Example: Save state for delta comparison
       m_previousValue = m_currentValue;
}

See also

AfterUpdate()

Implements imod::IObserver.

EnsureModelsDetached()

void imod::CMultiModelObserverBase::EnsureModelsDetached

(

)

Ensure all attached models are detached.

If there are some attached models they will be detached and removed from observed list.

GetModelCount()

int imod::CMultiModelObserverBase::GetModelCount

(

)

const

Gets the number of connected models.

GetModelPtr()

IModel * imod::CMultiModelObserverBase::GetModelPtr

(

int

modelIndex

)

const

Get access to connected model with the index index.

Deprecated:

use GetObservedModel instead.

GetObservedModel()

IModel * imod::CMultiModelObserverBase::GetObservedModel

(

int

modelIndex

)

const

Get access to connected model with the index index.

Parameters

modelIndex

index of model.

IsModelAttached()

virtual bool imod::CMultiModelObserverBase::IsModelAttached ( const IModel *  modelPtr ) const

overridevirtual

Checks if the specified model is currently attached to this observer.

This method allows querying whether a specific model is being observed, or whether any model at all is attached.

Parameters

modelPtr

Pointer to the model object to check. If nullptr, checks whether any model is attached to this observer.

Returns

true if the specified model (or any model when modelPtr is nullptr) is attached to this observer, false otherwise.

// Check if a specific model is attached
if (observer->IsModelAttached(myModel)) {
       // This specific model is being observed
}
 
// Check if any model is attached
if (observer->IsModelAttached(nullptr)) {
       // At least one model is attached
}

See also

OnModelAttached(), OnModelDetached()

Implements imod::IObserver.

OnModelAttached()

virtual bool imod::CMultiModelObserverBase::OnModelAttached ( IModel *  modelPtr, istd::IChangeable::ChangeSet &  changeMask  )

overridevirtual

Callback invoked when an observable model is about to be attached to this observer.

This method is called by the model when attempting to establish an observer relationship. The implementation should:

1. Validate that the model is of an acceptable type
2. Set the changeMask to specify which changes to monitor
3. Return true to accept the attachment, or false to reject it

Parameters

modelPtr	Pointer to the model object being attached. Never nullptr.
changeMask	Output parameter where the observer specifies which change types it wants to be notified about. Set the appropriate change flags using changeMask.Set(changeId). An empty mask means the observer wants all changes.

Returns

true if the model is accepted and attachment succeeds, false to reject the attachment (e.g., if the model is of incompatible type).

Note

After successful attachment, the observer should initialize its state based on the current model data.

The changeMask allows filtering notifications for better performance. Only changes matching the mask will trigger AfterUpdate() calls.

virtual bool OnModelAttached(IModel* modelPtr, 
                            istd::IChangeable::ChangeSet& changeMask)
{
       // Type check
       CMyModel* model = dynamic_cast<CMyModel*>(modelPtr);
       if (!model) return false;
       
       // Set up change filtering
       changeMask.Set(CMyModel::CF_DATA_CHANGED);
       changeMask.Set(CMyModel::CF_STATUS_CHANGED);
       // Don't set CF_INTERNAL_CHANGED - we don't care about those
       
       // Initialize view from current model state
       UpdateViewFromModel(model);
       return true;
}

See also

OnModelDetached(), IsModelAttached(), AfterUpdate()

Implements imod::IObserver.

Reimplemented in imod::TMultiModelObserverBase< ModelInterface >.

OnModelDetached()

virtual bool imod::CMultiModelObserverBase::OnModelDetached ( IModel *  modelPtr )

overridevirtual

Callback invoked when an observable model is about to be detached from this observer.

This method is called when the observer-model relationship is being terminated, either explicitly or because the model is being destroyed. The implementation should clean up any state or resources related to this model.

Parameters

modelPtr

Pointer to the model object being detached

Returns

true if the detachment was handled successfully, false otherwise

Note

After this call, the observer should not access the model pointer anymore.

This method may be called even if OnModelAttached() previously returned false.

Clean up any cached data or references to this model.

virtual bool OnModelDetached(IModel* modelPtr)
{
       if (m_currentModel == modelPtr) {
              // Clear any cached data
              m_cachedData.clear();
              m_currentModel = nullptr;
              
              // Update UI to show no model is attached
              ClearDisplay();
              return true;
       }
       return false;
}

See also

OnModelAttached(), IsModelAttached()

Implements imod::IObserver.

OnUpdate()

virtual void imod::CMultiModelObserverBase::OnUpdate ( IModel *  modelPtr, const istd::IChangeable::ChangeSet &  changeSet  )

protectedvirtual

Called on update of observed model.

This method is designed to be overload by derrived classes.

SetObservedIds()

void imod::CMultiModelObserverBase::SetObservedIds

(

const istd::IChangeable::ChangeSet &

changeMask

)

Set list of ID's beeing observed.

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The documentation for this class was generated from the following file:

• Acf/Include/imod/CMultiModelObserverBase.h