Base class for all data objects in ITK. More...

#include <itkDataObject.h>

Inheritance diagram for itk::DataObject:

Collaboration diagram for itk::DataObject:

Public Types
typedef SmartPointer< const Self >	ConstPointer
typedef std::string	DataObjectIdentifierType
typedef std::vector< Pointer > ::size_type	DataObjectPointerArraySizeType
typedef SmartPointer< Self >	Pointer
typedef DataObject	Self
typedef Object	Superclass
Public Member Functions
virtual void	CopyInformation (const DataObject *)
virtual void	DataHasBeenGenerated ()
void	DisconnectPipeline ()
bool	GetDataReleased () const
virtual const char *	GetNameOfClass () const
virtual const bool &	GetReleaseDataFlag ()
SmartPointerForwardReference < ProcessObject >	GetSource () const
DataObjectPointerArraySizeType	GetSourceOutputIndex () const
const DataObjectIdentifierType &	GetSourceOutputName () const
virtual unsigned long	GetUpdateMTime () const
virtual void	Initialize ()
virtual void	PrepareForNewData ()
virtual void	PropagateRequestedRegion ()
void	ReleaseData ()
virtual void	ReleaseDataFlagOff ()
virtual void	ReleaseDataFlagOn ()
virtual bool	RequestedRegionIsOutsideOfTheBufferedRegion ()
virtual void	ResetPipeline ()
void	SetReleaseDataFlag (bool flag)
virtual void	SetRequestedRegion (const DataObject *)
virtual void	SetRequestedRegionToLargestPossibleRegion ()
bool	ShouldIReleaseData () const
virtual void	Update ()
virtual void	UpdateOutputData ()
virtual void	UpdateOutputInformation ()
virtual bool	VerifyRequestedRegion ()

void	SetPipelineMTime (unsigned long time)
virtual const unsigned long &	GetPipelineMTime ()

virtual void	SetRealTimeStamp (RealTimeStamp _arg)
virtual const RealTimeStamp &	GetRealTimeStamp ()
Static Public Member Functions
static bool	GetGlobalReleaseDataFlag ()
static void	GlobalReleaseDataFlagOff ()
static void	GlobalReleaseDataFlagOn ()
static void	SetGlobalReleaseDataFlag (bool val)
Protected Member Functions
virtual void	PropagateResetPipeline ()
Private Member Functions
bool	ConnectSource (ProcessObject *s, const DataObjectIdentifierType &name)
	DataObject (const Self &)
bool	DisconnectSource (ProcessObject *s, const DataObjectIdentifierType &name)
void	operator= (const Self &)
Private Attributes
bool	m_DataReleased
unsigned long	m_PipelineMTime
RealTimeStamp	m_RealTimeStamp
bool	m_ReleaseDataFlag
WeakPointer< ProcessObject >	m_Source
DataObjectIdentifierType	m_SourceOutputName
TimeStamp	m_UpdateMTime
Static Private Attributes
static bool	m_GlobalReleaseDataFlag
Friends
class	DataObjectError
class	ProcessObject
virtual void	Graft (const DataObject *)
	DataObject ()
	~DataObject ()
void	PrintSelf (std::ostream &os, Indent indent) const

Detailed Description

Base class for all data objects in ITK.

This is the base class for all data objects in the Insight data processing pipeline. A data object is an object that represents and provides access to data. ProcessObjects (i.e., filters) operate on input data objects, producing new data objects as output. ProcessObject and DataObject are connected together into data flow pipelines.

The data flow pipeline architecture requires that DataObjects and ProcessObjects negotiate the flow of information. When the tail of a pipeline is instructed to Update(), a series of requests are propagated up the pipeline (from a ProcessObject to its inputs (DataObjects), from these inputs to their sources (ProcessObjects), etc.). A call to Update() entails 3 passes up the pipeline (though not all passes will traverse the entire pipeline). The first pass up the pipeline determines when various components of the pipeline were last modified and hence which components will need to be updated. As this first pass in unwinding, meta information about the DataObjects (for instance image spacing and data size) are passed down the pipeline. The second pass up the pipeline propagates a request for a specific piece of information (for instance a sub-region of an image). A request for a piece of a DataObject is propagated to its source, from there to its inputs, etc. allowing each ProcessObject to determine whether (1) it can already satisfy the request (the requested block of data is already available) or (2) the ProcessObject will need to request a new block of data on input to satisfy the output request. Finally, a pass is made up the pipeline to actually calculate the values for the various blocks of data requested (i.e. pixel values are finally calculated). This final pass will only traverse up the pipeline as far as the first two passes have identified. For instance, to satisfy a given request at the tail of a pipeline, only the lower few ProcessObjects may have to re-execute.

There are three types of information negotiated by the pipeline (prior to actual calculation of the bulk data): modified times, meta data, and regions. The modified times keep track of when various data objects were last modified and/updated and the when the various process objects were modified. The meta data is any extra information about the data object that is not part of the bulk data. For instance, an Image maintains pixel spacing and origin meta data. Finally, the pipeline negotiation process passes requests up the pipeline in the form of Regions. A DataObject can have as many as three regions (which themselves could be considered meta data): LargestPossibleRegion, RequestedRegion, and BufferedRegion. The LargestPossibleRegion is the entirety of the dataset (for instance how big is the dataset on disk). LargestPossibleRegions are negotiated during the first pass of a pipeline update (via the method ProcessObject::GenerateOutputInformation() which is called from ProcessObject::UpdateOutputInformation(). The RequestedRegion is the amount of the DataObject that is requested by the user or pipeline. RequestedRegions are negotiated during the second pass of a pipeline update (via the methods ProcessObject::EnlargeOutputRequestedRegion(), ProcessObject::GenerateOutputRequestedRegion(), ProcessObject::GenerateInputRequestedRegion() which are called from ProcessObject::PropagateRequestedRegion()). The BufferedRegion is the amount of the DataObject that is currently in memory. BufferedRegions are defined during the final pass of a pipeline update (when ProcessObjects finally calculate the bulk data via the methods ProcessObject::GenerateData() or ProcessObject::ThreadedGenerateData() which are called by ProcessObject::UpdateOutputData()). These three regions can be different but must satisfy the relationship RequestedRegion <= BufferedRegion <= LargestPossibleRegion. For instance, an Image could be 512x512x200 on disk (LargestPossibleRegion) but the application may only have a 256x256x50 section of the dataset in memory (BufferedRegion) and the user wants to operate on a 100x100x1 section of the buffer (RequestedRegion).

Region negotiation is not applicable for all types of DataObjects. For instance, an EquivalencyTable of segmentation labels can be passed from ProcessObject to ProcessObject as any other DataObject but an EquivalencyTable does not support the concept of a sub-region. Therefore, the region negotiations at the DataObject (superclass) level are implemented as "abstract" concepts (not to be confused with a C++ abstract methods), allowing subclasses to provide specialized implementations on an as needed basis. There are five methods provided in DataObject that a subclass of DataObject may have to override for that particular type of DataObject to flow through the pipeline. These methods should only have to be specialized for DataObjects that do support regions. These methods are:

void UpdateOutputInformation(): This method implements the first pass of the pipeline update mechanism outlined above. It is responsible for identifying when upstream components of the pipeline have been change (ModifiedTimes and Pipeline ModifiedTimes) and is responsible for propagating meta data through the pipeline. In the simplest case, this method simply calls the DataObject's source's UpdateOutputInformation() method (this is the default implementation). For DataObjects that support streaming, this method also propagates LargestPossibleRegions to downstream ProcessObjects.

bool VerifyRequestedRegion(): Verify that the RequestedRegion is within the LargestPossibleRegion. For DataObjects that do not support Regions, this method always returns true.

bool RequestedRegionIsOutsideOfTheBufferedRegion(): Determine whether the RequestedRegion is outside of the current BufferedRegion. This method is used by the second pass of a pipeline update outlined above. It is used to determine whether a filter needs to re-execute in order to satisfy a given request. For DataObjects that do not support Regions, this method always returns false. By always returning false, these types of DataObjects will update solely on the basis of modified times (wherease Images update based on either modified times or the RequestedRegion needs). If this method always returned true, the DataObject would be updated on every single call to Update() (not recommended).

void SetRequestedRegion(const DataObject *): Sets the RequestedRegion of this DataObject to match the RequestedRegion of the DataObject that is passed in as a parameter. This method is used by ProcessObject::GenerateOutputRequestedRegion() and by ProcessObject::SetNthOutput(). In the former case, it used as an abstract API so that a ProcessObject can copy a requested region from one output to all its outputs without knowing the particular subclass of DataObject. In the latter case, it used when a ProcessObject has to create an output object to replace one of its outputs (and needs to copy the former object's RequestedRegion). In either case, it allows ProcessObject to perform these actions without knowing the specifics about the particular subclass of DataObject. For DataObjects that do not support Regions, this method does nothing.

void SetRequestedRegionToLargestPossibleRegion(): Sets the RequestedRegion of this DataObject to match its LargestPossibleRegion. This method is used to force a filter to produce all of its output on the next call to Update(). For DataObjects that do not support Regions, this method does nothing.

See also:: ProcessObject; ImageBase; Mesh

Definition at line 275 of file itkDataObject.h.

Member Typedef Documentation

typedef SmartPointer< const Self > itk::DataObject::ConstPointer

Reimplemented from itk::Object.

Definition at line 282 of file itkDataObject.h.

typedef std::string itk::DataObject::DataObjectIdentifierType

Definition at line 284 of file itkDataObject.h.

typedef std::vector< Pointer >::size_type itk::DataObject::DataObjectPointerArraySizeType

Which of the source's outputs corresponds to this data object?

Definition at line 314 of file itkDataObject.h.

typedef SmartPointer< Self > itk::DataObject::Pointer

Reimplemented from itk::Object.

Definition at line 281 of file itkDataObject.h.

typedef DataObject itk::DataObject::Self

Standard class typedefs.

Reimplemented from itk::Object.

Definition at line 279 of file itkDataObject.h.

typedef Object itk::DataObject::Superclass

Reimplemented from itk::Object.

Definition at line 280 of file itkDataObject.h.

Constructor & Destructor Documentation

itk::DataObject::DataObject ( ) [protected]

Method for grafting the content of one data object into another one. This method is intended to be overloaded by derived classes. Each one of them should use dynamic_casting in order to verify that the grafted object is actually of the same type as the class on which the Graft() method was invoked.

itk::DataObject::~DataObject ( ) [protected]

Method for grafting the content of one data object into another one. This method is intended to be overloaded by derived classes. Each one of them should use dynamic_casting in order to verify that the grafted object is actually of the same type as the class on which the Graft() method was invoked.

itk::DataObject::DataObject ( const Self & ) [private]

Member Function Documentation

bool itk::DataObject::ConnectSource	(	ProcessObject *	s,
		const DataObjectIdentifierType &	name
	)		`[private]`

Connect the specified process object to the data object. This should only be called from a process object. The second parameter indicates which of the source's outputs corresponds to this data object.

virtual void itk::DataObject::CopyInformation ( const DataObject * ) [inline, virtual]

Copy information from the specified data set. This method is part of the pipeline execution model. By default, a ProcessObject will copy meta-data from the first input to all of its outputs. See ProcessObject::GenerateOutputInformation(). Each subclass of DataObject is responsible for being able to copy whatever meta-data it needs from from another DataObject. The default implementation of this method is empty. If a subclass overrides this method, it should always call its superclass' version.

Definition at line 467 of file itkDataObject.h.

virtual void itk::DataObject::DataHasBeenGenerated ( ) [virtual]

Inform the pipeline mechanism that data has been generated. This method is called by ProcessObject::UpdateOutputData() once the process object has finished generating its data. This essentially marks the DataObject as being updated and ready for use.

void itk::DataObject::DisconnectPipeline ( )

Separate this data object from the pipeline. This routine disconnects a data object from the upstream pipeline. Hence an Update() from downstream will not propagate back past this data object. To completely isolate this data object from the pipeline, the application must remove this data object from any filters which it is connected as the input.

bool itk::DataObject::DisconnectSource	(	ProcessObject *	s,
		const DataObjectIdentifierType &	name
	)		`[private]`

Disconnect the specified process object from the data object. This should only be called from a process object. An application should call DataObject::DisconnectPipeline() if it wants to disconnect a data object from a pipeline. The second parameter indicates which of the source's outputs corresponds to this data object. If the specified source output name does not match the name cached when the data object was connected to the pipeline (see ConnectSource), then nothing is done.

bool itk::DataObject::GetDataReleased ( ) const [inline]

Get the flag indicating the data has been released.

Definition at line 354 of file itkDataObject.h.

static bool itk::DataObject::GetGlobalReleaseDataFlag ( ) [static]

virtual const char* itk::DataObject::GetNameOfClass ( ) const [virtual]

Run-time type information (and related methods).

Reimplemented from itk::Object.

virtual const unsigned long& itk::DataObject::GetPipelineMTime ( ) [virtual]

The maximum MTime of all upstream filters and data objects. This does not include the MTime of this data object.

virtual const RealTimeStamp& itk::DataObject::GetRealTimeStamp ( ) [virtual]

RealTime stamp for the last time this DataObject was generated. By default, the real time stamp is initialized to the origin of the Unix epoch. That is the time 00:00:00 UTC on 1 January 1970 (or 1970-01-01T00:00:00Z ISO 8601)

virtual const bool& itk::DataObject::GetReleaseDataFlag ( ) [virtual]

SmartPointerForwardReference< ProcessObject > itk::DataObject::GetSource ( ) const

Get the process object that generated this data object. If there is no process object, then the data object has been disconnected from the pipeline, or the data object was created manually. (Note: we cannot use the GetObjectMacro() defined in itkMacro because the mutual dependency of DataObject and ProcessObject causes compile problems. Also, a forward reference smart pointer is returned, not a smart pointer, because of the circular dependency between the process and data object.)

GetSource() returns a SmartPointerForwardReference and not a WeakPointer because it is assumed the code calling GetSource() wants to hold a long term reference to the source.

DataObjectPointerArraySizeType itk::DataObject::GetSourceOutputIndex ( ) const

const DataObjectIdentifierType& itk::DataObject::GetSourceOutputName ( ) const

Which of the source's outputs corresponds to this data object?

virtual unsigned long itk::DataObject::GetUpdateMTime ( ) const [virtual]

MTime for the last time this DataObject was generated.

static void itk::DataObject::GlobalReleaseDataFlagOff ( ) [inline, static]

Definition at line 340 of file itkDataObject.h.

static void itk::DataObject::GlobalReleaseDataFlagOn ( ) [inline, static]

Definition at line 338 of file itkDataObject.h.

virtual void itk::DataObject::Graft ( const DataObject * ) [inline, virtual]

Method for grafting the content of one data object into another one. This method is intended to be overloaded by derived classes. Each one of them should use dynamic_casting in order to verify that the grafted object is actually of the same type as the class on which the Graft() method was invoked.

Definition at line 481 of file itkDataObject.h.

virtual void itk::DataObject::Initialize ( ) [virtual]

Restore the data object to its initial state. This means releasing memory.

void itk::DataObject::operator= ( const Self & ) [private]

virtual void itk::DataObject::PrepareForNewData ( ) [inline, virtual]

Setup a DataObject to receive new data. This method is called by the pipeline mechanism on each output of filter that needs to execute. The default implementation is to return a DataObject to its initial state. This may involve releasing previously allocated bulk data. Subclasses of DataObject may want to override this method and/or the Initialize() method if they want a different default behavior (for instance a DataObject might want finer control over its bulk data memory management).

Definition at line 418 of file itkDataObject.h.

void itk::DataObject::PrintSelf	(	std::ostream &	os,
		Indent	indent
	)		const `[protected, virtual]`

Method for grafting the content of one data object into another one. This method is intended to be overloaded by derived classes. Each one of them should use dynamic_casting in order to verify that the grafted object is actually of the same type as the class on which the Graft() method was invoked.

Reimplemented from itk::Object.

virtual void itk::DataObject::PropagateRequestedRegion ( ) [virtual]

Methods to update the pipeline. Called internally by the pipeline mechanism.

virtual void itk::DataObject::PropagateResetPipeline ( ) [protected, virtual]

Propagate a call to ResetPipeline(). Called only from ProcessObject.

void itk::DataObject::ReleaseData ( )

Release data back to system to conserve memory resource. Used during pipeline execution. Releasing this data does not make down-stream data invalid, so it does not modify the MTime of this data object.

virtual void itk::DataObject::ReleaseDataFlagOff ( ) [virtual]

virtual void itk::DataObject::ReleaseDataFlagOn ( ) [virtual]

virtual bool itk::DataObject::RequestedRegionIsOutsideOfTheBufferedRegion ( ) [inline, virtual]

Determine whether the RequestedRegion is outside of the BufferedRegion. This method returns true if the RequestedRegion is outside the BufferedRegion (true if at least one pixel is outside). This is used by the pipeline mechanism to determine whether a filter needs to re-execute in order to satisfy the current request. If the current RequestedRegion is already inside the BufferedRegion from the previous execution (and the current filter is up to date), then a given filter does not need to re-execute

Reimplemented in itk::ImageBase< VImageDimension >, itk::PointSet< TPixelType, VDimension, TMeshTraits >, itk::SpatialObject< VDimension >, itk::QuadEdgeMesh< TPixel, VDimension, TTraits >, itk::LevelSetBase< TInput, VDimension, TOutput, TDomain >, itk::TemporalDataObject, itk::ImageBase< ::itk::GetImageDimension< TLabelObject >::ImageDimension >, itk::ImageBase< ::itk::GetImageDimension< VectorImage< TPixelType, Dimension > >::ImageDimension >, itk::ImageBase< ::itk::GetImageDimension< TImage >::ImageDimension >, itk::PointSet< TPixel, VDimension, TTraits >, itk::PointSet< TCoordType, VDimension, DefaultDynamicMeshTraits< TCoordType, 2, 2, TCoordType > >, itk::SpatialObject< 3 >, itk::SpatialObject< TDimension >, itk::SpatialObject< ::itk::GetMeshDimension< TMesh >::PointDimension >, itk::LevelSetBase< TMesh::PointIdentifier, TMesh::PointDimension, TMesh::PixelType, TMesh >, itk::LevelSetBase< TInput, VDimension, TOutput, ImageBase< VDimension > >, itk::LevelSetBase< Index< VDimension >, VDimension, TOutput, ImageBase< VDimension > >, itk::LevelSetBase< Index< VDimension >, VDimension, TImage::PixelType, ImageBase< VDimension > >, and itk::LevelSetBase< Index< VDimension >, VDimension, int8_t, ImageBase< VDimension > >.

Definition at line 441 of file itkDataObject.h.

virtual void itk::DataObject::ResetPipeline ( ) [virtual]

Reset the pipeline. If an exception is thrown during an Update(), the pipeline may be in an inconsistent state. This method clears the internal state of the pipeline so Update() can be called.

static void itk::DataObject::SetGlobalReleaseDataFlag ( bool val ) [static]

Turn on/off a flag to control whether every object releases its data after being used by a filter. Being a global flag, it controls the behavior of all DataObjects and ProcessObjects.

void itk::DataObject::SetPipelineMTime ( unsigned long time ) [inline]

The maximum MTime of all upstream filters and data objects. This does not include the MTime of this data object.

Definition at line 393 of file itkDataObject.h.

virtual void itk::DataObject::SetRealTimeStamp ( RealTimeStamp _arg ) [virtual]

RealTime stamp for the last time this DataObject was generated. By default, the real time stamp is initialized to the origin of the Unix epoch. That is the time 00:00:00 UTC on 1 January 1970 (or 1970-01-01T00:00:00Z ISO 8601)

void itk::DataObject::SetReleaseDataFlag ( bool flag ) [inline]

Turn on/off a flag to control whether this object's data is released after being used by a filter.

Definition at line 323 of file itkDataObject.h.

virtual void itk::DataObject::SetRequestedRegion ( const DataObject * ) [inline, virtual]

Set the requested region from this data object to match the requested region of the data object passed in as a parameter. For DataObject's that do not support Regions, this method does nothing. Subclasses of DataObject that do support Regions, provide an alternative implementation.

Definition at line 474 of file itkDataObject.h.

virtual void itk::DataObject::SetRequestedRegionToLargestPossibleRegion ( ) [inline, virtual]

Set the RequestedRegion to the LargestPossibleRegion. This forces a filter to produce all of the output in one execution (i.e. not streaming) on the next call to Update().

Definition at line 430 of file itkDataObject.h.

bool itk::DataObject::ShouldIReleaseData ( ) const

Return flag indicating whether data should be released after use by a filter.

virtual void itk::DataObject::Update ( ) [virtual]

Provides opportunity for the data object to insure internal consistency before access. Also causes owning source/filter (if any) to update itself. The Update() method is composed of UpdateOutputInformation(), PropagateRequestedRegion(), and UpdateOutputData(). This method may call methods that throw an InvalidRequestedRegionError exception. This exception will leave the pipeline in an inconsistent state. You will need to call ResetPipeline() on the last ProcessObject in your pipeline in order to restore the pipeline to a state where you can call Update() again.

Referenced by itk::WatershedImageFilter< TInputImage >::GetBasicSegmentation().

virtual void itk::DataObject::UpdateOutputData ( ) [virtual]

virtual void itk::DataObject::UpdateOutputInformation ( ) [virtual]

Update the information for this DataObject so that it can be used as an output of a ProcessObject. This method is used in the pipeline mechanism to propagate information and initialize the meta data associated with a DataObject. Any implementation of this method in a derived class is assumed to call its source's ProcessObject::UpdateOutputInformation() which determines modified times, LargestPossibleRegions, and any extra meta data like spacing, origin, etc. Default implementation simply call's it's source's UpdateOutputInformation().

virtual bool itk::DataObject::VerifyRequestedRegion ( ) [inline, virtual]

Verify that the RequestedRegion is within the LargestPossibleRegion.

If the RequestedRegion is not within the LargestPossibleRegion, then the filter cannot possibly satisfy the request. This method returns true if the request can be satisfied (even if it will be necessary to process the entire LargestPossibleRegion) and returns false otherwise. This method is used by PropagateRequestedRegion(). PropagateRequestedRegion() throws a InvalidRequestedRegionError exception if the requested region is not within the LargestPossibleRegion. Default implementation simply returns true in order to support DataObjects that do not need regions (for instance itk::EquivalencyTable).

Definition at line 456 of file itkDataObject.h.

Friends And Related Function Documentation

friend class DataObjectError [friend]

Definition at line 536 of file itkDataObject.h.

friend class ProcessObject [friend]

Friends of DataObject

Definition at line 535 of file itkDataObject.h.

Member Data Documentation

bool itk::DataObject::m_DataReleased [private]

Definition at line 509 of file itkDataObject.h.

bool itk::DataObject::m_GlobalReleaseDataFlag [static, private]

Static member that controls global data release after use by filter.

Definition at line 516 of file itkDataObject.h.

unsigned long itk::DataObject::m_PipelineMTime [private]

The maximum MTime of all upstream filters and data objects. This does not include the MTime of this data object.

Definition at line 513 of file itkDataObject.h.

RealTimeStamp itk::DataObject::m_RealTimeStamp [private]

When, in real time, this data was generated.

Definition at line 506 of file itkDataObject.h.

bool itk::DataObject::m_ReleaseDataFlag [private]

Definition at line 508 of file itkDataObject.h.

WeakPointer< ProcessObject > itk::DataObject::m_Source [private]

Who generated this data?

Definition at line 496 of file itkDataObject.h.

DataObjectIdentifierType itk::DataObject::m_SourceOutputName [private]

Definition at line 497 of file itkDataObject.h.

TimeStamp itk::DataObject::m_UpdateMTime [private]

When was this data last generated? This time stap is an integer number and it is intended to synchronize the activities of the pipeline. It doesn't relates to the clock time of acquiring or processing the data.

Definition at line 503 of file itkDataObject.h.

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

itkDataObject.h

Public Types

Public Member Functions

Static Public Member Functions

Protected Member Functions

Private Member Functions

Private Attributes

Static Private Attributes

Friends

Detailed Description

Member Typedef Documentation

Constructor & Destructor Documentation

Member Function Documentation

Friends And Related Function Documentation

Member Data Documentation