How do I use directory globbing in JDK7

Question

I have been trying to use the new globbing feature in JDK7, starting from the documentation and examples

I can get globs such as "glob:*.dat" to work with the

Files.walkFileTree(startingDir, finder);

example but I have been unable to get the "**" syntax working. I would like to be able to create something like:

matcher = FileSystems.getDefault().getPathMatcher("glob:" + "foo/**/bar/*.dat");

and would be grateful for a simple example. I am using Windows 7.

UPDATE: @Oleg and @JBNizet make it clear that the "/" syntax is OS-independent. Note that the Javadocs suggest that OS-dependent syntax is also possible (?required)

STILL PROBLEMS: Have taken @Nizet and edited as follows:

@Test
public void testStackoverflowGlobber() throws IOException {
    final PathMatcher matcher =
 FileSystems.getDefault().getPathMatcher("glob:*.cml");
        Files.walkFileTree(Paths.get("d:/petermr-workspace/jumbo-converters/jumbo-converters-cli/src/test/resources"), new SimpleFileVisitor<Path>() {
            @Override
            public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
                System.out.println("try>> "+file);
                if (matcher.matches(file)) {
                    System.out.println("MATCHES>>"+file);
                }
                return FileVisitResult.CONTINUE;
            }
        @Override
        public FileVisitResult visitFileFailed(Path file, IOException exc) throws IOException {
            return FileVisitResult.CONTINUE;
        }
    });
}

and this gives output such as:

try>> d:\petermr-workspace\jumbo-converters\jumbo-converters-cli\src\test\resources\examples\cdx\r19.cdx
try>> d:\petermr-workspace\jumbo-converters\jumbo-converters-cli\src\test\resources\examples\cdx\r19.cdxml
try>> d:\petermr-workspace\jumbo-converters\jumbo-converters-cli\src\test\resources\examples\cdx\r19.cml
try>> d:\petermr-workspace\jumbo-converters\jumbo-converters-cli\src\test\resources\examples\cdx\r19.ref.cdxml
try>> d:\petermr-workspace\jumbo-converters\jumbo-converters-cli\src\test\resources\examples\cdx\r19.ref.cml
try>> d:\petermr-workspace\jumbo-converters\jumbo-converters-cli\src\test\resources\examples\cif\aa2004.cml

but no evidence of matching

Woodnote

/ will work fine on any Windows system if that's your concern – Cesena

@Oleg thanks. So I have got some logic wrong or assumed the methods have different functionality. is File.separator therefore wrong? [I find the official documentation rather sketchy] – Woodnote

have you tried "glob:**/*.cml"? – Clayson

@Kristof thanks - it seems that you have to use the ** component – Woodnote

Answer 1

Here's a working example which displays all the zip files in any descendant directory of d:/:

public static void main(String[] args) throws IOException {
    final PathMatcher matcher = FileSystems.getDefault().getPathMatcher("glob:d:/**/*.zip");
    Files.walkFileTree(Paths.get("d:/"), new SimpleFileVisitor<Path>() {
        @Override
        public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
            if (matcher.matches(file)) {
                System.out.println(file);
            }
            return FileVisitResult.CONTINUE;
        }

        @Override
        public FileVisitResult visitFileFailed(Path file, IOException exc) throws IOException {
            return FileVisitResult.CONTINUE;
        }
    });
}

As you see, using forward slashes works on Windows.

Vilma

Thanks. Will it check relative file paths? – Woodnote

have accepted this as it's the only answer and it tackled the problem of file separator. But I can't get it to work on my environment. The globbing syntax seems rather lightly documented and there aren't clear examples. Oh well, will probably work tomorrow... – Woodnote

If you even want to remove the drive specific use following glob:*/**/*.zip – Grabowski

the drive specific part can be removed with pattern glob:**/*.zip even the extension glob:**/*.* – Roxie

Ummm.... this works, but it's not efficient. If your pattern is glob:/foo/bar/baz/**/*.zip then it will walk the entire file tree, not just the /foo/bar/baz component. – Mccluskey

Answer 2

You need to start your glob with **

matcher = FileSystems.getDefault().getPathMatcher("glob:**/foo/**/bar/*.dat");

Otherwise, calling

matcher.matches(file)

attempts to match the full path to the file against a regular expression that starts with the relative path (/foo/), rather than with the absolute path (d:/petermr-workspace/.../foo).

Prepending the ** to the glob just tells it to ignore the beginning of the absolute path.

Sorensen