JavaTutorials/PrintDirectoryTree.java

//Java/JavaTutorials/PrintDirectoryTree.java
//Matthew Ellison
// Created: 01-07-2020
//Modified: 01-07-2020
//This class will step through a directory and print out the contents

//TODO: I am still learning what exactly this code does. I need to insert some comments as soon as I learn what everything is doing.


import java.util.EnumSet;
import java.io.*;
import java.nio.file.*;
import java.nio.file.attribute.*;
import static java.nio.file.FileVisitResult.*;


public class PrintDirectoryTree{
	public static void main(String[] args) throws IOException{
		String searchDirectory = "";	//This string holds the directory that will be printed

		//This makes sure something is set for the directory
		if(args.length == 1){
			//Set the argument as the directory
			searchDirectory = args[0];
		}
		else if(args.length == 0){
			//Set the entire C drive as the directory if none was given
			searchDirectory = "C:/";
		}
		else{
			//Print an error and exit if there are mutliple arguments sent
			System.out.print("There are too many parameters!");
			return;
		}

		try{
			Path startingDir = Paths.get(searchDirectory);
			EnumSet<FileVisitOption> opts = EnumSet.of(FileVisitOption.FOLLOW_LINKS);
			PrintTree pf = new PrintTree();
			Files.walkFileTree(startingDir, opts, Integer.MAX_VALUE, pf);
		}
		catch(Exception x){
			System.err.print("Exception raised: " + x);
		}
	}
	public static class PrintTree extends SimpleFileVisitor<Path>{
		@Override
		public FileVisitResult visitFile(Path file, BasicFileAttributes attr){
			//This prints out a particular string when a certain type of file is found
			if(attr.isSymbolicLink()){
				System.out.format("Symbolic Link: %s", file);
			}
			else if(attr.isRegularFile()){
				System.out.format("Real File: %s", file);
			}
			else{
				System.out.format("Other: %s", file);
			}

			//This prints out the size of any given file
			System.out.println("(" + attr.size() + " bytes)");
			return CONTINUE;
		}
		@Override
		public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs){
			//This simply prints out the name of the directory
			System.out.format("Directory: %s\n", dir);
			return CONTINUE;
		}
		@Override
		public FileVisitResult visitFileFailed(Path file, IOException exc){
			//This prints out whatever error message was thrown
			System.err.println(exc);
			return CONTINUE;
		}
	}
}