Class FilteringFeatureReader<T extends FeatureType,​F extends Feature>

  • All Implemented Interfaces:
    Closeable, AutoCloseable, DelegatingFeatureReader<T,​F>, FeatureReader<T,​F>
    Direct Known Subclasses:

    public class FilteringFeatureReader<T extends FeatureType,​F extends Feature>
    extends Object
    implements DelegatingFeatureReader<T,​F>
    Basic support for a FeatureReader 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.

    Chris Holmes
    • Constructor Detail

      • FilteringFeatureReader

        public FilteringFeatureReader​(FeatureReader<T,​F> featureReader,
                                      Filter filter)
        Creates a new instance of AbstractFeatureReader

        Please don't call this method with Filter.INCLUDE or Filter.EXCLUDE (consider not filtering and EmptyFeatureReader instead)

        featureReader - FeatureReader being filtered
        filter - Filter used to limit the results of featureReader
    • Method Detail

      • close

        public void close()
                   throws IOException
        Description copied from interface: FeatureReader
        Release the underlying resources associated with this stream.
        Specified by:
        close in interface AutoCloseable
        Specified by:
        close in interface Closeable
        Specified by:
        close in interface FeatureReader<T extends FeatureType,​F extends Feature>
        IOException - if an I/O error occurs
      • getFeatureType

        public T getFeatureType()
        Description copied from interface: FeatureReader
        Return the FeatureType this reader has been configured to create.
        Specified by:
        getFeatureType in interface FeatureReader<T extends FeatureType,​F extends Feature>
        the FeatureType of the Features this FeatureReader will create.
      • hasNext

        public boolean hasNext()
                        throws IOException
        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 interface FeatureReader<T extends FeatureType,​F extends Feature>
        true if we have additional content
        IOException - If the reader we are filtering encounters a problem
        DataSourceException - See IOException