QGIS API Documentation 3.41.0-Master (d5b93354e9c)
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Uses another iterator as backend and writes features to the cache. More...
#include <qgscachedfeatureiterator.h>
Public Member Functions | |
QgsCachedFeatureWriterIterator (QgsVectorLayerCache *vlCache, const QgsFeatureRequest &featureRequest) | |
This constructor creates a feature iterator, which queries the backend and caches retrieved features. | |
bool | close () override |
Close this iterator. | |
bool | rewind () override |
Rewind to the beginning of the iterator. | |
Public Member Functions inherited from QgsAbstractFeatureIterator | |
QgsAbstractFeatureIterator (const QgsFeatureRequest &request) | |
base class constructor - stores the iteration parameters | |
virtual | ~QgsAbstractFeatureIterator ()=default |
destructor makes sure that the iterator is closed properly | |
bool | compileFailed () const |
Indicator if there was an error when sending the compiled query to the server. | |
CompileStatus | compileStatus () const |
Returns the status of expression compilation for filter expression requests. | |
virtual bool | isValid () const |
Returns if this iterator is valid. | |
virtual bool | nextFeature (QgsFeature &f) |
Fetch next feature and stores in f, returns true on success. | |
virtual void | setInterruptionChecker (QgsFeedback *interruptionChecker) |
Attach an object that can be queried regularly by the iterator to check if it must stopped. | |
Protected Member Functions | |
bool | fetchFeature (QgsFeature &f) override |
Implementation for fetching a feature. | |
Protected Member Functions inherited from QgsAbstractFeatureIterator | |
void | deref () |
Remove reference, delete if refs == 0. | |
QgsRectangle | filterRectToSourceCrs (const QgsCoordinateTransform &transform) const |
Returns a rectangle representing the original request's QgsFeatureRequest::filterRect(). | |
void | geometryToDestinationCrs (QgsFeature &feature, const QgsCoordinateTransform &transform) const |
Transforms feature's geometry according to the specified coordinate transform. | |
virtual bool | nextFeatureFilterExpression (QgsFeature &f) |
By default, the iterator will fetch all features and check if the feature matches the expression. | |
virtual bool | nextFeatureFilterFids (QgsFeature &f) |
By default, the iterator will fetch all features and check if the id is in the request. | |
virtual bool | prepareSimplification (const QgsSimplifyMethod &simplifyMethod) |
Setup the simplification of geometries to fetch using the specified simplify method. | |
void | ref () |
Add reference. | |
RequestToSourceCrsResult | updateRequestToSourceCrs (QgsFeatureRequest &request, const QgsCoordinateTransform &transform) const |
Update a QgsFeatureRequest so that spatial filters are transformed to the source's coordinate reference system. | |
Additional Inherited Members | |
Public Types inherited from QgsAbstractFeatureIterator | |
enum | CompileStatus { NoCompilation , PartiallyCompiled , Compiled } |
Status of expression compilation for filter expression requests. More... | |
enum class | RequestToSourceCrsResult : int { Success , DistanceWithinMustBeCheckedManually } |
Possible results from the updateRequestToSourceCrs() method. More... | |
Protected Attributes inherited from QgsAbstractFeatureIterator | |
bool | mClosed = false |
Sets to true , as soon as the iterator is closed. | |
bool | mCompileFailed = false |
CompileStatus | mCompileStatus = NoCompilation |
Status of compilation of filter expression. | |
long long | mFetchedCount = 0 |
Number of features already fetched by iterator. | |
QgsFeatureRequest | mRequest |
A copy of the feature request. | |
bool | mValid = true |
An invalid state of a feature iterator indicates that there was a problem with even getting it up and running. | |
bool | mZombie = false |
A feature iterator may be closed already but still be serving features from the cache. | |
int | refs = 0 |
reference counting (to allow seamless copying of QgsFeatureIterator instances) | |
Uses another iterator as backend and writes features to the cache.
Definition at line 103 of file qgscachedfeatureiterator.h.
QgsCachedFeatureWriterIterator::QgsCachedFeatureWriterIterator | ( | QgsVectorLayerCache * | vlCache, |
const QgsFeatureRequest & | featureRequest | ||
) |
This constructor creates a feature iterator, which queries the backend and caches retrieved features.
vlCache | The vector layer cache to use |
featureRequest | The feature request to answer |
Definition at line 139 of file qgscachedfeatureiterator.cpp.
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overridevirtual |
Close this iterator.
No further features will be available.
true
if successful Implements QgsAbstractFeatureIterator.
Definition at line 193 of file qgscachedfeatureiterator.cpp.
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overrideprotectedvirtual |
Implementation for fetching a feature.
f | Will write to this feature |
true
if the operation was OK Implements QgsAbstractFeatureIterator.
Definition at line 163 of file qgscachedfeatureiterator.cpp.
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overridevirtual |
Rewind to the beginning of the iterator.
true
if the operation was OK Implements QgsAbstractFeatureIterator.
Definition at line 187 of file qgscachedfeatureiterator.cpp.