HI all,
Java NIO2 providers
(https://docs.oracle.com/javase/8/docs/api/java/nio/file/spi/FileSystemProvider.html)
works by providing filesystems via SPI. Ideally one would just write the
appropriate classes and drop them on the classpath . This allows
somebody does to write something like:
Paths.get('gz:/path/to/compressed.gz')
This all works fine when done within a normal application but it fails
when used within GroovyConsole or just running a normal Groovy script.
ONe would expect the following just to work
@Grab('org.ysb33r.nio:nio-gz-provider-commons:0.1')
@Grab('org.slf4j:slf4j-simple:1.7.5')
import java.nio.file.*
Paths.get('gz:/path/to/compressed.gz')
However the following workaround is required
@Grab('org.ysb33r.nio:nio-gz-provider-commons:0.1')
@Grab('org.slf4j:slf4j-simple:1.7.5')
import java.nio.file.*
FileSystem fs
try {
fs = FileSystems.getFileSystem(gzURI)
} catch(FileSystemNotFoundException) {
fs =
FileSystems.newFileSystem(gzURI,[:],this.class.classLoader.parent.parent)
}
Path gzPath = fs.provider().getPath(gzURI)
NOTE: Using
@GrabConfig(initContextClassLoader=true,systemClassLoader=true) does not
solve the problem in this case
At Gr8Conf I sat with with Andres, Jochen and Guillaume to work through
this. The issue that that providers are loaded via the system class
loader, whereas with GroovyConsole and command-line Groovy it will be
loaded via an instance of RootLoader. This leads to one having to
manually loading the filesystem.
From the point of view of someone using NIO2 providers this is
surprising behaviour. One would expect it just to work out of the box
(as per the Javadoc for FileSystemProvider).
My question is now. Is there something that can be done to way
GroovyConsole and Groovy scripts are started so that the expectd
behaviour of NIO2 providers can be obtained? (Maybe adding an additional
method to GrabConfig?).
Groovy luck.
--
Schalk W. Cronjé
Twitter / Ello / Toeter : @ysb33r
