bhauer / wildcard

Efficient file system pattern matching in Java

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Wildcard is a small Java library that performs efficient pattern matching of files and directories. Paths can be matched with wildcards or regular expressions. Matched files can be easily copied, deleted, zipped, etc.

Glob matching

The glob method collects files and directories using literal characters and optional wildcards:

Paths paths = new Paths();
paths.glob("/some/directory", "resources");
paths.glob("/some/directory", "images/**/*.jpg", "!**/.svn/**");

The first parameter defines the root directory of the search. Subsequent parameters are a variable number of search patterns. The following wildcards are supported in search patterns:

`?`Matches any single character. Eg, `something?` collects any path that is named "something" plus any character.
`**`Matches any characters up to the next slash. Eg, `**/**/something**` collects any path that has two directories, then a file or directory that starts with the name "something".
`**`Matches any characters. Eg, `**/something/**` collects any path that contains a directory named "something".
!A pattern starting with an exclamation point (!) causes paths matched by the pattern to be excluded, even if other patterns would select the paths.

When using glob, the search is done as efficiently as possible. Directories are not traversed if none of the search patterns can match them.

Glob is also used when constructor parameters are specified:

Paths paths = new Paths("/some/directory", "resources");

Regex matching

Regular expressions can be used to collect files and directories:

Paths paths = new Paths();
paths.regex("/some/directory", "images.*\\.jpg", "!.*/\\.svn/.*");

Regex patterns that being with ! caused matched paths to be excluded, even if other patterns would select the paths.

Regular expressions have more expressive power, but it comes at a price. When using regex, the search is not done as efficiently as with glob. All directories and files under the root are traversed, even if none of the search patterns can match them.

Pipe delimited patterns

If glob or regex is passed only one parameter, it may be a root directory and then any number of search patterns, delimited by pipe (|) characters:

Paths paths = new Paths();
paths.glob("/some/directory|resources");
paths.glob("/some/directory|images/**/*.jpg|!**/.svn/**");

This is useful in cases where it is more convenient to use a single string to describe what files to collect.

If glob is passed only one parameter that is not pipe delimited, or if only exclude patterns are specified (using the ! character), then an additional search pattern of ** is implied.

Utility methods

The glob and regex methods can be called repeatedly to collect paths from different root directories. Internally, a Paths instance holds all the paths matched and remembers each root directory where the search was performed. This greatly simplifies many tasks. The Paths class has utility methods for manipulating the paths, eg:

Paths paths = new Paths();
paths.glob("/some/directory", "**/images/*/image0?.*");
paths.copyTo("/another/directory");

This collects all JPG files in any directory under "/some/directory". It then copies those files to "/another/directory". Note that the directory structure under the root directory is preserved. Eg, if you had these files:

/some/directory/stuff.jpg
/some/directory/otherstuff.gif
/some/directory/animals/cat.jpg
/some/directory/animals/dog.jpg
/some/directory/animals/giraffe.tga

The result after the copy would be:

/another/directory/stuff.jpg
/another/directory/animals/cat.jpg
/another/directory/animals/dog.jpg

The Paths class has methods to copy, delete, and zip the paths. It also has methods to obtain the individual paths in various ways, so you can take whatever action you like:

for (String fullPath : new Paths(".", "*.png")) { ... }
for (String dirName : new Paths(".").dirsOnly().getNames()) { ... }
for (File file : new Paths(".", "*.jpg").getFiles()) { ... )

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Efficient file system pattern matching in Java


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