Using the SimpleFileVisitor class to traverse file systems : SimpleFileVisitor « JDK 7 « Java

1. Java
2. JDK 7
3. SimpleFileVisitor

Using the SimpleFileVisitor class to traverse file systems

import java.io.IOException;
import java.nio.file.FileVisitResult;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.SimpleFileVisitor;
import java.nio.file.attribute.BasicFileAttributes;

class ListFiles extends SimpleFileVisitor<Path> {
  private final int indentionAmount = 3;
  private int indentionLevel;

  public ListFiles() {
    indentionLevel = 0;
  }

  private void indent() {
    for (int i = 0; i < indentionLevel; i++) {
      System.out.print(' ');
    }
  }

  @Override
  public FileVisitResult visitFile(Path file, BasicFileAttributes attributes) {
    indent();
    System.out.println("Visiting file:" + file.getFileName());
    return FileVisitResult.CONTINUE;
  }

  @Override
  public FileVisitResult postVisitDirectory(Path directory, IOException e)
      throws IOException {
    indentionLevel -= indentionAmount;
    indent();
    System.out.println("Finished with the directory: "
        + directory.getFileName());
    return FileVisitResult.CONTINUE;
  }

  @Override
  public FileVisitResult preVisitDirectory(Path directory,
      BasicFileAttributes attributes) throws IOException {
    indent();
    System.out.println("About to traverse the directory: "
        + directory.getFileName());
    indentionLevel += indentionAmount;
    return FileVisitResult.CONTINUE;
  }

  @Override
  public FileVisitResult visitFileFailed(Path file, IOException exc)
      throws IOException {
    System.out.println("A file traversal error ocurred");
    return super.visitFileFailed(file, exc);
  }
}

public class Test {

  public static void main(String[] args) {
    try {
      Path path = Paths.get("/home");
      ListFiles listFiles = new ListFiles();
      Files.walkFileTree(path, listFiles);
    } catch (IOException ex) {
      ex.printStackTrace();
    }
  }
}

 

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