IlvLookAheadFeatureIterator Class Reference

Defines an abstract class for feature iterators that have a look ahead ability. More...

#include <ilviews/maps/laiterator.h>

Inheritance diagram for IlvLookAheadFeatureIterator:

Public Member Functions
virtual IlvMapFeatureId *	getNextFeatureId (IlvMapsError &status)=0
	Returns the ID of the next feature that will be returned by this feature iterator. More...
virtual IlBoolean	skipNextFeature (IlvMapsError &status)=0
	Skips the next feature. More...
Public Member Functions inherited from IlvMapFeatureIterator
virtual IlvClassInfo *	getClassInfo () const =0
	Returns the class information for this feature iterator. More...
virtual IlvFeatureRenderer *	getDefaultFeatureRenderer (IlvDisplay *display)=0
	Returns the default renderer for this feature iterator. More...
virtual IlvMapsError	getInitStatus () const =0
	Checks the initialization status of this feature iterator. More...
virtual IlBoolean	getLowerRightCorner (IlvCoordinate &result) const =0
	Returns the lower right corner of the rectangle containing all the map features of this iterator. More...
virtual const IlvMapFeature *	getNextFeature (IlvMapsError &status)=0
	Returns the next map feature of the iterator, or 0 if the iteration is finished. The returned feature is owned by the feature iterator. More...
virtual const IlvProjection *	getProjection () const =0
	Returns the projection in which the geometric coordinates of the map features are expressed or 0 if the feature iterator returns ungeoreferenced map features. More...
virtual IlBoolean	getUpperLeftCorner (IlvCoordinate &result) const =0
	Returns the upper left corner of the rectangle containing all the map features of this iterator. More...
virtual void	setSourceProjection (IlvProjection *projection)
	Sets the projection of geometries generated by this feature iterator. This method is to be used when feature source is not georeferenced. The default implementation of this method does nothing. More...

Additional Inherited Members
Static Public Member Functions inherited from IlvMapFeatureIterator
static IlvClassInfo *	ClassInfo ()
	Returns the class information of the class. More...
static IlvClassInfo **	ClassInfoRef ()
	Returns the address of the class information of the class. More...

Detailed Description

Defines an abstract class for feature iterators that have a look ahead ability.

Library: ilvmaps

Feature iterators subclassing this class can fetch the ID of the next feature that will be returned by getNextFeature, and skip the next feature. This behavior is needed for optimization in cases where the ID allows you to decide if the next feature is to be completely read or not.

Member Function Documentation

virtual IlvMapFeatureId* IlvLookAheadFeatureIterator::getNextFeatureId ( IlvMapsError &  status )

pure virtual

Returns the ID of the next feature that will be returned by this feature iterator.

When this method returns 0, it does not mean that there are no more features available, but only that no more IDs are available.

Returns

The next feature ID, or 0 if no more feature IDs are available.

Implemented in IlvShapeSHPReader, and IlvShapeFileReader.

virtual IlBoolean IlvLookAheadFeatureIterator::skipNextFeature ( IlvMapsError &  status )

pure virtual

Skips the next feature.

The feature normally returned by getNextFeature() is skipped.

Returns

IlTrue if the skipped feature is not the last feature.

Implemented in IlvShapeSHPReader, and IlvShapeFileReader.