FChange Class Reference

#include <Change.h>

Inheritance diagram for FChange:

Public Types
enum class	EChangeStyle { InPlaceSwap , CommandPattern }

Public Member Functions
virtual EChangeStyle	GetChangeType ()=0
virtual TUniquePtr< FChange >	Execute (UObject *Object)=0
virtual void	Apply (UObject *Object)=0
virtual void	Revert (UObject *Object)=0
virtual bool	HasExpired (UObject *Object) const
virtual void	AddReferencedObjects (FReferenceCollector &Collector)
virtual FString	ToString () const =0
virtual void	PrintToLog (FFeedbackContext &FeedbackContext, const int32 IndentLevel=0)
virtual	~FChange ()

Protected Member Functions
	FChange ()

Private Member Functions
	FChange (const FChange &)=delete
FChange &	operator= (const FChange &)=delete

Detailed Description

FChange modifies a UObject and is meant to be used to implement undo/redo. The change is embedded in an FTransaction which executes it instead of the standard serialization transaction (cannot be combined - see FTransaction).

The original FChange style (used by MeshEditor) was that calling Execute() would return a new FChange that applies the opposite action, and FTransaction would swap the two at each undo/redo step (eg a "DeleteObject" FChange would return a "CreateObject" FChange)

The alternative "Command Pattern"-style FChange calls Apply() and Revert() on a single FChange.

FChange may eventually be deprecated. You should subclass FSwapChange and FCommandChange to implement these different styles.

Definition at line 31 of file Change.h.

Member Enumeration Documentation

EChangeStyle

enum class FChange::EChangeStyle

strong

Enumerator
InPlaceSwap
CommandPattern

Definition at line 35 of file Change.h.

Constructor & Destructor Documentation

~FChange()

virtual FChange::~FChange ( )

inlinevirtual

Virtual destructor

Definition at line 66 of file Change.h.

FChange() [1/2]

FChange::FChange ( )

inlineprotected

Protected default constructor

Definition at line 73 of file Change.h.

FChange() [2/2]

FChange::FChange ( const FChange & )

privatedelete

Member Function Documentation

AddReferencedObjects()

virtual void FChange::AddReferencedObjects ( FReferenceCollector & Collector )

inlinevirtual

Used by GC to collect referenced objects.

Definition at line 57 of file Change.h.

Apply()

virtual void FChange::Apply ( UObject * Object )

pure virtual

Makes the change to the object

Implemented in FSwapChange.

Execute()

virtual TUniquePtr< FChange > FChange::Execute ( UObject * Object )

pure virtual

Makes the change to the object, returning a new change that can be used to perfectly roll back this change

Implemented in FCommandChange, and FCompoundChange.

GetChangeType()

virtual EChangeStyle FChange::GetChangeType ( )

pure virtual

What style of change is this

Implemented in FSwapChange, and FCommandChange.

HasExpired()

virtual bool FChange::HasExpired ( UObject * Object ) const

inlinevirtual

Returns

true if this Change has Expired, ie it will no longer have any effect and could be skipped by undo/redo

Definition at line 54 of file Change.h.

operator=()

FChange & FChange::operator= ( const FChange & )

privatedelete

PrintToLog()

virtual void FChange::PrintToLog ( FFeedbackContext & FeedbackContext, const int32 IndentLevel = 0 )

virtual

Prints this change to the log, including sub-changes if there are any. For compound changes, there might be multiple lines. You should not need to override this function.

Reimplemented in FCompoundChange.

Revert()

virtual void FChange::Revert ( UObject * Object )

pure virtual

Reverts change to the object

Implemented in FSwapChange.

ToString()

virtual FString FChange::ToString ( ) const

pure virtual

Describes this change (for debugging)

Implemented in FCompoundChange.

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

• C:/Users/lachl/Downloads/ArkServerAPI_NEW/ASA/AsaApi/AsaApi/Core/Public/API/UE/Misc/Change.h