Subgroup: Abstract
Class: QgsAbstractCacheIndex¶
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class
qgis.core.
QgsAbstractCacheIndex
¶ Bases:
sip.wrapper
Abstract base class for cache indices
Methods
flush
Sometimes, the whole cache changes its state and its easier to just withdraw everything. flushFeature
Is called, whenever a feature is removed from the cache. getCacheIterator
Is called, when a feature request is issued on a cached layer. requestCompleted
Implement this method to update the the indices, in case you need information contained by the request to properly index. Attributes
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flush
(self)¶ 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.
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flushFeature
(self, fid: int)¶ 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 successfully answer a request.
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getCacheIterator
(self, featureIterator: QgsFeatureIterator, featureRequest: QgsFeatureRequest) → bool¶ 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 willbe assigned in case this index is able to answer the request and the return value is true. :param featureRequest: The feature request, for which this index is queried.
Returns: True, if this index holds the information to answer the request.
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requestCompleted
(self, featureRequest: QgsFeatureRequest, fids: object)¶ 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
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