FileSystemProvider delegation

[Michael Hall]

I have a 'file' default FileSystemProvider that I am trying in some instances to have delegate to the normal platform FileSystemProvider.
In the getPath(String first, String more) method for the custom FileSystem method if it decides to delegate back it currently does this...

In TrueZipFileSystem.java (extends FileSystem)
getPath(String first, String... more) 
...
return new PathDelegate(((TrueZipFileSystemProvider)provider).getPriorProvider().getPath(pathURI));

Where PathDelegate is a wrapper for the platform instance Path that provides some convenience methods. These are pretty much the convenience methods that the zip demo assumes it's Path class to provide.

However, if I try to use this returned platform Path wrapper instance like this...

		Path absdirfile = Paths.get("/Users");
		System.out.println("Paths absolute dir " + absdirfile + " class " + absdirfile.getClass().getName());
		System.out.println(absdirfile + " is directory " + Files.isDirectory(absdirfile));

It gets...

Paths absolute dir org.truezip.PathDelegate at cb5de2 class org.truezip.PathDelegate
Exception in thread "main" java.nio.file.ProviderMismatchException
	at sun.nio.fs.UnixPath.toUnixPath(UnixPath.java:200)
	at sun.nio.fs.UnixFileSystemProvider.getFileAttributeView(UnixFileSystemProvider.java:128)
	at sun.nio.fs.BsdFileSystemProvider.getFileAttributeView(BsdFileSystemProvider.java:57)
	at sun.nio.fs.UnixFileSystemProvider.readAttributes(UnixFileSystemProvider.java:157)
	at sun.nio.fs.BsdFileSystemProvider.readAttributes(BsdFileSystemProvider.java:80)
	at java.nio.file.Files.readAttributes(Files.java:1669)
	at java.nio.file.Files.isDirectory(Files.java:2118)
	at BasicSetupTester.main(BasicSetupTester.java:13)

Per the javadoc for ProviderMismatchException
Unchecked exception thrown when an attempt is made to invoke a method on an object created by one file system provider with a parameter created by a different file system provider.

So the wrapper class can't be used? It's the only parm. If the platform instance will only work with one FileSystem and Path that are also platform type, it makes delegation back to it from other providers more difficult, doesn't it?

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mail.openjdk.java.net/pipermail/nio-dev/attachments/20110428/143e9309/attachment.html