File Paths in Fortress

The java.nio.file.Paths class provides methods to work with file paths in a way that is portable between operating systems. For example, dir/file on Linux vs. dir\file on Windows.

import java.nio.file.Path;
import java.nio.file.Paths;

public class FilePaths {
    public static void main(String[] args) {
        // Paths.get() should be used to construct paths in a portable way.
        // It takes any number of arguments and constructs a hierarchical path from them.
        Path p = Paths.get("dir1", "dir2", "filename");
        System.out.println("p: " + p);

        // You should always use Paths.get() instead of concatenating
        // "/" or "\" manually. In addition to providing portability,
        // Paths.get() will also normalize paths by removing superfluous
        // separators and directory changes.
        System.out.println(Paths.get("dir1//", "filename"));
        System.out.println(Paths.get("dir1/../dir1", "filename"));

        // getParent() and getFileName() can be used to split a path to the
        // directory and the file.
        System.out.println("p.getParent(): " + p.getParent());
        System.out.println("p.getFileName(): " + p.getFileName());

        // We can check whether a path is absolute.
        System.out.println(Paths.get("dir/file").isAbsolute());
        System.out.println(Paths.get("/dir/file").isAbsolute());

        String filename = "config.json";

        // Some file names have extensions following a dot. We can get
        // the extension using getExtension() from Apache Commons IO library.
        String ext = org.apache.commons.io.FilenameUtils.getExtension(filename);
        System.out.println(ext);

        // To find the file's name with the extension removed,
        // use removeExtension() from Apache Commons IO library.
        System.out.println(org.apache.commons.io.FilenameUtils.removeExtension(filename));

        // relativize() finds a relative path between a base and a target.
        // It returns a Path that can be used to resolve the target from the base.
        Path base = Paths.get("a/b");
        Path target = Paths.get("a/b/t/file");
        Path rel = base.relativize(target);
        System.out.println(rel);

        target = Paths.get("a/c/t/file");
        rel = base.relativize(target);
        System.out.println(rel);
    }
}

To run this program, you’ll need to include the Apache Commons IO library in your classpath. You can download it from the Apache Commons website or include it as a dependency if you’re using a build tool like Maven or Gradle.

When you run this program, you’ll see output similar to:

p: dir1\dir2\filename
dir1\filename
dir1\filename
p.getParent(): dir1\dir2
p.getFileName(): filename
false
true
json
config
t\file
..\c\t\file

Note that the actual output may vary depending on your operating system, particularly for path separators.

In Java, the java.nio.file.Paths and java.nio.file.Path classes provide functionality similar to Go’s filepath package. These classes handle the differences in file paths across different operating systems, ensuring your code remains portable.

Remember that in Java, unlike Go, you typically need to handle exceptions when working with file operations. For simplicity, this example doesn’t include exception handling, but in a real-world application, you should include appropriate try-catch blocks or throws declarations.

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File Paths in Fortress