Package org.geotools.data
Class FilteringFeatureReader<T extends FeatureType,F extends Feature>
Object
FilteringFeatureReader<T,F>
- All Implemented Interfaces:
Closeable
,AutoCloseable
,DelegatingFeatureReader<T,
,F> FeatureReader<T,
F>
- Direct Known Subclasses:
FilteringSimpleFeatureReader
public class FilteringFeatureReader<T extends FeatureType,F extends Feature>
extends Object
implements DelegatingFeatureReader<T,F>
Basic support for a FeatureReader<SimpleFeatureType, SimpleFeature> that does filtering. I think that filtering
should perhaps be done in the AttributeReader. I'm still having a bit of trouble with the split between
attributeReader and featureReader as to where the hooks for advanced processing like filtering should take place. See
my note on hasNext(), as the method is currently broken and there are more optimizations that could take place if we
had a FilteringAttributeReader. So this class may go, but I thought I'd put the ideas into code.
Jody here - changed hasNext() to peek as required.
- Author:
- Chris Holmes
-
Field Summary
FieldsModifier and TypeFieldDescriptionprotected final FeatureReader<T,
F> protected final Filter
protected F
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Constructor Summary
ConstructorsConstructorDescriptionFilteringFeatureReader
(FeatureReader<T, F> featureReader, Filter filter) Creates a new instance of AbstractFeatureReader -
Method Summary
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Field Details
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featureReader
-
filter
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next
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Constructor Details
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FilteringFeatureReader
Creates a new instance of AbstractFeatureReaderPlease don't call this method with Filter.INCLUDE or Filter.EXCLUDE (consider not filtering and EmptyFeatureReader instead)
- Parameters:
featureReader
- FeatureReader<SimpleFeatureType, SimpleFeature> being filteredfilter
- Filter used to limit the results of featureReader
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Method Details
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getDelegate
- Specified by:
getDelegate
in interfaceDelegatingFeatureReader<T extends FeatureType,
F extends Feature> - Returns:
- THe delegate reader.
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next
Description copied from interface:FeatureReader
Reads the next Feature in the FeatureReader.- Specified by:
next
in interfaceFeatureReader<T extends FeatureType,
F extends Feature> - Returns:
- The next feature in the reader.
- Throws:
IOException
- If an error occurs reading the Feature.NoSuchElementException
- If there are no more Features in the Reader.IllegalAttributeException
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close
Description copied from interface:FeatureReader
Release the underlying resources associated with this stream.- Specified by:
close
in interfaceAutoCloseable
- Specified by:
close
in interfaceCloseable
- Specified by:
close
in interfaceFeatureReader<T extends FeatureType,
F extends Feature> - Throws:
IOException
- if an I/O error occurs
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getFeatureType
Description copied from interface:FeatureReader
Return the FeatureType this reader has been configured to create.- Specified by:
getFeatureType
in interfaceFeatureReader<T extends FeatureType,
F extends Feature> - Returns:
- the FeatureType of the Features this FeatureReader will create.
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hasNext
Query for additional content.This class will peek ahead to see if there is additional content.
Chris has pointed out that we could make use of AttributeReader based filtering:
"Also doing things in the Attribute Reader would allow us to do the smart filtering, only looking at the attributes needed for comparison, whereas doing filtering here means we have to create an entire feature each time."- Specified by:
hasNext
in interfaceFeatureReader<T extends FeatureType,
F extends Feature> - Returns:
true
if we have additional content- Throws:
IOException
- If the reader we are filtering encounters a problemDataSourceException
- See IOException
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