Abstract base class for cache indices. More...
#include <qgscacheindex.h>
Public Member Functions | |
| QgsAbstractCacheIndex () | |
| virtual | ~QgsAbstractCacheIndex () |
| virtual void | flush ()=0 |
| Sometimes, the whole cache changes its state and its easier to just withdraw everything. More... | |
| virtual void | flushFeature (const QgsFeatureId fid)=0 |
| Is called, whenever a feature is removed from the cache. More... | |
| virtual bool | getCacheIterator (QgsFeatureIterator &featureIterator, const QgsFeatureRequest &featureRequest)=0 |
| Is called, when a feature request is issued on a cached layer. More... | |
| virtual void | requestCompleted (const QgsFeatureRequest &featureRequest, const QgsFeatureIds &fids) |
| Implement this method to update the the indices, in case you need information contained by the request to properly index. More... | |
Detailed Description
Abstract base class for cache indices.
Definition at line 29 of file qgscacheindex.h.
Constructor & Destructor Documentation
◆ QgsAbstractCacheIndex()
| QgsAbstractCacheIndex::QgsAbstractCacheIndex | ( | ) |
Definition at line 19 of file qgscacheindex.cpp.
◆ ~QgsAbstractCacheIndex()
|
virtual |
Definition at line 23 of file qgscacheindex.cpp.
Member Function Documentation
◆ flush()
|
pure virtual |
Sometimes, the whole cache changes its state and its easier to just withdraw everything.
In this case, this method is issued. Be sure to clear all cache information in here.
Implemented in QgsCacheIndexFeatureId.
◆ flushFeature()
|
pure virtual |
Is called, whenever a feature is removed from the cache.
You should update your indexes, so they become invalid in case this feature was required to successfuly answer a request.
Implemented in QgsCacheIndexFeatureId.
◆ getCacheIterator()
|
pure virtual |
Is called, when a feature request is issued on a cached layer.
If this cache index is able to completely answer the feature request, it will return true and set the iterator to a valid iterator over the cached features. If it is not able it will return false.
- Parameters
-
featureIterator A reference to a QgsFeatureIterator. A valid featureIterator will be assigned in case this index is able to answer the request and the return value is true. featureRequest The feature request, for which this index is queried.
- Returns
- True, if this index holds the information to answer the request.
Implemented in QgsCacheIndexFeatureId.
◆ requestCompleted()
|
virtual |
Implement this method to update the the indices, in case you need information contained by the request to properly index.
(E.g. spatial index) Does nothing by default
- Parameters
-
featureRequest The feature request that was answered fids The feature ids that have been returned
Reimplemented in QgsCacheIndexFeatureId.
Definition at line 27 of file qgscacheindex.cpp.
The documentation for this class was generated from the following files:
- /tmp/buildd/qgis-2.18.21+99unstable/src/core/qgscacheindex.h
- /tmp/buildd/qgis-2.18.21+99unstable/src/core/qgscacheindex.cpp
