Hello all
I would like to propose the following modifications to the Shapefile reader:
* Rename as ShapefileStore for consistency with NetcdfStore.
* Declare ShapefileStore as a subclass of DataStore:
o Implement the getMetadata() method using the information
currently stored in fields like version, xmin, xmax, etc.
* Turn public fields into private fields instead.
* Add a getEnvelope(Query) method which returns the (xmin, ymin, etc.)
values.
o The Query argument would be an empty class for now, but still
defined as a placeholder for future developments.
* Add a getFeatures(Query) method which returns a FeatureCollection
(extends Collection<Feature>).
To explain more about the last point: the intend is to be able to read
large set of Features without loading all of them in memory. So instead
than storing all Features in a HashMap, we would allow implementations
to return a collection backed by an iterator instantiating the Features
on the fly. Such Iterator is the same idea than java.sql.ResultSet.
Using a method instead than direct to a public field has two purposes:
* Allows to specify a filter or other query aspects.
* Allows to returns an Autocloseable collection for implementations
that perform their I/O operations on the fly.
So instead of iterating on features like below:
for (Feature f : shapefile.FeatureMap.values()) {
// ... do some stuff ...
}
We would do:
try (FeatureCollection features = shapefile.getFeatures(myQuery)) {
for (Feature f : features) {
// ... do some stuff ...
}
}
What do peoples think?
Martin
