Hi Matt.
Le mer. 20 janv. 2021 à 05:03, Matt Juntunen
<matt.juntu...@hotmail.com> a écrit :
>
> Hello,
>
> I've created GEOMETRY-115 and an associated PR [1] containing new modules for
> IO functionality. The new modules are
>
> * commons-geometry-core-io - Common space-independent interfaces and
> classes
> * commons-geometry-euclidean-io - Euclidean IO classes; currently
> contains support for the 3D formats TXT, CSV, and OBJ
>
> The API is based on a core BoundaryIOManager class that delegates to
> BoundaryReadHandler and BoundaryWriteHandler implementations based on the
> requested data format. For Euclidean 3D space, a convenience IO3D class is
> provided with static methods that delegate to a default manager instance. In
> addition to reading and writing the core geometric types for the library
> (ConvexPolygon3D, Triangle3D), the Euclidean module also supports reading and
> writing a FacetDefinition interface, which exposes simple, unvalidated
> geometric data. This is intended for accessing raw (possibly invalid)
> geometric data from files and writing data contained in external data
> structures (for example, a custom facet class). The example below is from the
> IO3D class documentation and demonstrates a read, transform, write operation
> using streams.
>
> final Path origFile = tempDir.resolve("orig.obj");
> final Path scaledFile = tempDir.resolve("scaled.csv");
>
> final DoublePrecisionContext precision = new
> EpsilonDoublePrecisionContext(1e-10);
> final BoundarySource3D src = Parallelepiped.unitCube(precision);
>
> IO3D.write(src, origFile);
>
> final AffineTransformMatrix3D transform =
> AffineTransformMatrix3D.createScale(2);
>
> try (Stream<Triangle3D> stream = IO3D.triangles(origFile, precision))
> {
> IO3D.write(stream.map(t -> t.transform(transform)), scaledFile);
> }
>
> Feedback is welcome.
The high-level API, illustrated in the example above, looks quite fine.
But we should enforce "separation of concerns"; in this particular case:
package "io" does not belong in "core".
The Java package
org.apache.commons.geometry.core
is defined the within the (maven) module
commons-geometry-core
The new Java package
org.apache.commons.geometry.core.io
is defined the within the (maven) module
commons-geometry-core-io
The (maven) module name is also often used to define the
Java 9+ module name for JPMS.[1]
IIUC, the package
org.apache.commons.geometry.core
and its "sub-package"
org.apache.commons.geometry.core.io
cannot belong to different (JPMS) modules, because (IIUC) a package
hierarchy cannot be shared across modules (since one of the purposes
is to organize "visibility").
Components should be JPMS-compatible.[2]
Fixing that would just require to
1. remove the two modules introduced in PR #130
commons-geometry-core-io
commons-geometry-euclidean-io
2. create one (maven) module
commons-geometry-io
owning the Java packages
org.apache.commons.geometry.io
org.apache.commons.geometry.io.core
org.apache.commons.geometry.io.euclidean
[If you think that it's really worth having separate modules for loading
"euclidean" data vs other space-types (not yet implemented IIUC),
point (2) would be adapted accordingly.]
This would fix both the JPMS issue, and the design issue.
Then, we had also discussed that it would have been more robust to
use a parser generator...
In either case, I'd suggest that we put the actual I/O classes in an
"internal" package, and only advertize the above high-level API (i.e. we
should not be expected to maintain compatibility of the parser code).
I haven't read all the code (sorry!), but in class "IO3D", I'm not convinced
by the usage of file "extensions" to determine how the contents should be
parsed. At first sight, an "enum"-based approach[3] would be more flexible
and clearer from a code design POV.
Regards,
Gilles
[1] https://www.oracle.com/corporate/features/understanding-java-9-modules.html
[2] See
https://gitbox.apache.org/repos/asf?p=commons-rng.git;a=tree;f=commons-rng-examples/examples-jpms;hb=HEAD
[3] See
https://gitbox.apache.org/repos/asf?p=commons-rng.git;a=blob;f=commons-rng-simple/src/main/java/org/apache/commons/rng/simple/RandomSource.java;h=65ca02fdc285fbb7ea8305008dbce21f571191d7;hb=HEAD
>
> Regards,
> Matt J
>
> [1] https://github.com/apache/commons-geometry/pull/130
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