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IlvLookAheadFeatureIterator Class Referenceabstract

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

#include <ilviews/maps/laiterator.h>

Inheritance diagram for IlvLookAheadFeatureIterator:
IlvMapFeatureIterator IlvShapeFileReader IlvShapeSHPReader

Public Member Functions

virtual ~IlvLookAheadFeatureIterator ()
 Destructor.
 
virtual IlvMapFeatureIdgetNextFeatureId (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 IlvClassInfogetClassInfo () const =0
 Returns the class information for this feature iterator. More...
 
virtual IlvFeatureRenderergetDefaultFeatureRenderer (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 IlvMapFeaturegetNextFeature (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 IlvProjectiongetProjection () 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. More...
 

Additional Inherited Members

- Static Public Member Functions inherited from IlvMapFeatureIterator
static IlvClassInfoClassInfo ()
 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 ot 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.


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