ConsumerExample.java

package enumexample;

import javax.swing.*;
import java.io.IOException;
import java.nio.file.*;
import java.nio.file.attribute.BasicFileAttributes;

/**
 * @author /u/Philboyd_Studge on 1/10/2016.
 */
public class ConsumerExample extends JFrame {

    JPanel panel = new JPanel();

    JProgressBar bar = new JProgressBar();
    Path path;
    int fileCount;

    public ConsumerExample(String pathName) throws IOException {
        path = Paths.get(pathName);
        getFileCount();
        bar.setMaximum(fileCount);
        this.setSize(400,300);
        bar.setStringPainted(true);
        panel.add(bar);
        this.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        this.setContentPane(panel);
        this.setVisible(true);
    }

    public void getFileCount() throws IOException {
        Files.walkFileTree(path, new SimpleFileVisitor<Path>(){
            @Override
            public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
                fileCount++;
                return super.visitFile(file, attrs);
            }
        });
        System.out.println(fileCount);
    }

    public void updateBar(int value) {
            bar.setValue(bar.getValue() + value);
     }

    public void updateBarString(String name) {
        updateBar(1);
        bar.setString(name);
    }

    public static void main(String[] args) throws IOException {
        ConsumerExample ce = new ConsumerExample("C:/BlitzPlus");
        FileVisitorConsumer fv = new FileVisitorConsumer(ce::updateBarString);
        Files.walkFileTree(ce.path,fv);
    }
}

FileVisitorConsumer.java

    package enumexample;

    import java.io.IOException;
    import java.nio.file.FileVisitResult;
    import java.nio.file.Path;
    import java.nio.file.SimpleFileVisitor;
    import java.nio.file.attribute.BasicFileAttributes;
    import java.util.function.Consumer;

    /**
     * @author /u/Philboyd_Studge on 1/10/2016.
     */
    public class FileVisitorConsumer extends SimpleFileVisitor<Path> {

        Consumer<String> consumer;

        public FileVisitorConsumer(Consumer<String> consumer) {
            super();
            this.consumer = consumer;
        }

        @Override
        public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
            consumer.accept(file.getFileName().toString());
            try {
                Thread.sleep(50); //adjust this or remove
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            return super.visitFile(file, attrs);
        }
    }