PathMatcher

PathMatcher is an interface in the Java NIO (New I/O) API that provides pattern-based matching for Path objects. It defines a single method, matches(Path path), which returns true if the given path conforms to the associated pattern.

PathMatcher instances are obtained from a file system using FileSystems.getDefault().getPathMatcher(String syntaxAndPattern). The argument combines a syntax indicator with a pattern, for example "glob:*.java" or "regex:^.*\\\\.java$". The syntax can be either glob or regex, and the pattern determines how paths are matched.

Glob patterns support wildcards such as * for zero or more characters within a path segment, ? for a single character, and ** for matching across directory levels. This makes PathMatcher useful for filtering files in directory trees or selectively processing paths that meet certain naming criteria. Regex patterns use standard Java regular expressions to express more complex matching rules.

PathMatcher is commonly used in file traversal and filtering operations, such as walking a directory tree with FileVisitor or filtering DirectoryStream results. Since the matching is performed against Path objects, the behavior respects the file system’s path semantics, including directory separators, and patterns can be anchored to match entire paths or specific segments depending on the syntax.

In summary, PathMatcher provides a flexible, pattern-based mechanism to test whether a Path matches a given criterion, supporting both glob and regular expression syntaxes for broad applicability in file handling and search tasks.

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