public interface CoordinateSequenceFilter
A filter can either record information about each coordinate,
or change the value of the coordinate.
Filters can be
used to implement operations such as coordinate transformations, centroid and
envelope computation, and many other functions.
Geometry classes support the concept of applying a
CoordinateSequenceFilter to each
CoordinateSequences they contain.
For maximum efficiency, the execution of filters can be short-circuited by using the
an example of the Gang-of-Four Visitor pattern.
Note: In general, it is preferable to treat Geometrys as immutable.
Mutation should be performed by creating a new Geometry object (see
GeometryTransformer for convenient ways to do this).
An exception to this rule is when a new Geometry has been created via
In this case mutating the Geometry will not cause aliasing issues,
and a filter is a convenient way to implement coordinate transformation.
|Modifier and Type
|Method and Description
Performs an operation on a coordinate in a
Reports whether the application of this filter can be terminated.
Reports whether the execution of this filter has modified the coordinates of the geometry.
void filter(CoordinateSequence seq, int i)
seq - the
CoordinateSequence to which the filter is applied
i - the index of the coordinate to apply the filter to
Geometry.geometryChanged() will be executed
after this filter has finished being executed.
Most filters can simply return a constant value reflecting whether they are able to change the coordinates.
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