Hash fundtion

Program.java

@@ -0,0 +1,75 @@
+import javax.swing.*;
+import java.io.*;
+import java.nio.file.Files;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+import java.util.Objects;
+import java.util.StringTokenizer;
+
+public class Program {
+    private Terminal terminal;
+    private String path;
+    private String option;
+
+    public Program() {
+        this.terminal = new Terminal();
+    }
+
+    public void start() throws IOException, NoSuchAlgorithmException {
+        StringTokenizer st= terminal.getInput();
+        setInput(st);
+
+        if (option.equalsIgnoreCase("list")) {
+            listCommand();
+        }
+        else if (option.equalsIgnoreCase("hash")) {
+            hashCommand();
+        }
+
+    }
+
+
+    private void setInput(StringTokenizer st) {
+        option = st.nextToken();
+        path = st.nextToken();
+    }
+
+
+
+    private void listCommand() {
+        File dir = new File(path);
+
+        for (File file : dir.listFiles()) {
+            System.out.println(file.getName() + " " + file.length() + "Byte");
+        }
+    }
+
+    private void hashCommand() throws IOException, NoSuchAlgorithmException {
+        File dir = new File(path);
+        FileFilter fileFilter = new FileFilter() {
+            @Override
+            public boolean accept(File pathname) {
+                return pathname.isFile();
+            }
+        };
+        MessageDigest md = MessageDigest.getInstance(("SHA-1"));
+        for (File file : Objects.requireNonNull(dir.listFiles(fileFilter))) {
+            BufferedReader br = new BufferedReader(new FileReader(file));
+            StringBuffer sb = new StringBuffer();
+            String line = null;
+            while ((line = br.readLine()) != null) {
+                sb.append(line);
+            }
+            md.update(sb.toString().getBytes());
+            byte[] byteData = md.digest();
+            sb.setLength(0);
+            for (int i = 0; i < byteData.length; i++) {
+                sb.append(Integer.toString((byteData[i]&0xff) + 0x100, 16).substring(1));
+            }
+
+            System.out.println(file.getName() + " " + sb.toString());
+            sb.setLength(0);
+        }
+    }
+
+}