fileVisitor

Builds a FileVisitor whose implementation is defined in builderAction.

By default, the returned file visitor visits all files and re-throws I/O errors, that is:

• FileVisitor.preVisitDirectory returns FileVisitResult.CONTINUE.

• FileVisitor.visitFile returns FileVisitResult.CONTINUE.

• FileVisitor.visitFileFailed re-throws the I/O exception that prevented the file from being visited.

• FileVisitor.postVisitDirectory returns FileVisitResult.CONTINUE if the directory iteration completes without an I/O exception; otherwise, it re-throws the I/O exception that caused the iteration to complete prematurely.

To override a function provide its implementation to the corresponding function of the FileVisitorBuilder that was passed as a receiver to builderAction. Note that each function can be overridden only once. Repeated override of a function throws IllegalStateException.

The builder is valid only inside builderAction function. Using it outside the function throws IllegalStateException.

Example:

val cleanVisitor = fileVisitor {
    onPreVisitDirectory { directory, _ ->
        if (directory.name == "build") {
            directory.deleteRecursively()
            FileVisitResult.SKIP_SUBTREE
        } else {
            FileVisitResult.CONTINUE
        }
    }

    onVisitFile { file, _ ->
        if (file.extension == "class") {
            file.deleteExisting()
        }
        FileVisitResult.CONTINUE
    }
}

See also