public class GeometryTransformer extends Object
Geometry
into
an output Geometry
, possibly changing its structure and type(s).
This class is a framework for implementing subclasses
which perform transformations on
various different Geometry subclasses.
It provides an easy way of applying specific transformations
to given geometry types, while allowing unhandled types to be simply copied.
Also, the framework ensures that if subcomponents change type
the parent geometries types change appropriately to maintain valid structure.
Subclasses will override whichever transformX
methods
they need to to handle particular Geometry types.
A typically usage would be a transformation class that transforms Polygons into
Polygons, LineStrings or Points, depending on the geometry of the input
(For instance, a simplification operation).
This class would likely need to override the transformMultiPolygon(MultiPolygon, Geometry)
method to ensure that if input Polygons change type the result is a GeometryCollection,
not a MultiPolygon.
The default behaviour of this class is simply to recursively transform each Geometry component into an identical object by deep copying down to the level of, but not including, coordinates.
All transformX
methods may return null
,
to avoid creating empty or invalid geometry objects. This will be handled correctly
by the transformer. transformXXX
methods should always return valid
geometry - if they cannot do this they should return null
(for instance, it may not be possible for a transformLineString implementation
to return at least two points - in this case, it should return null
).
The transform(Geometry)
method itself will always
return a non-null Geometry object (but this may be empty).
GeometryEditor
Constructor and Description |
---|
GeometryTransformer() |
Modifier and Type | Method and Description |
---|---|
Geometry |
getInputGeometry()
Utility function to make input geometry available
|
Geometry |
transform(Geometry inputGeom) |
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