SHA-1 Calculator (Java+Swing) / http://inaz2.hatenablog.com/entry/2016/04/26/203045

SHA1Calculator.jar

SHA1Calculator.java

import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Arrays;
import java.util.List;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.SwingWorker;
import javax.swing.TransferHandler;
import javax.swing.border.EmptyBorder;
import javax.swing.table.DefaultTableModel;

public class SHA1Calculator extends JFrame {

	private JPanel contentPane;
	private DefaultTableModel model;

	/**
	 * Launch the application.
	 */
	public static void main(String[] args) {
		EventQueue.invokeLater(new Runnable() {
			public void run() {
				try {
					SHA1Calculator frame = new SHA1Calculator();
					frame.setVisible(true);
				} catch (Exception e) {
					e.printStackTrace();
				}
			}
		});
	}

	/**
	 * Create the frame.
	 */
	public SHA1Calculator() {
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		setBounds(100, 100, 600, 300);  // expanded default frame size
		contentPane = new JPanel();
		contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
		contentPane.setLayout(new BorderLayout(0, 0));
		setContentPane(contentPane);

		setTitle("SHA-1 Calculator");

		// create scrollable JTable
		model = new DefaultTableModel(new String[]{"File Path", "sha1sum"}, 0);
		JTable table = new JTable(model);
		JScrollPane scrollPane = new JScrollPane(table);
		contentPane.add(scrollPane);

		// enable file drop
		contentPane.setTransferHandler(new DropFileHandler());
	}

	private class DropFileHandler extends TransferHandler {
		@Override
		public boolean canImport(TransferSupport support) {
			// Check if dropped data is files
			return (support.isDrop()
					&& support.isDataFlavorSupported(DataFlavor.javaFileListFlavor));
		}

		@Override
		@SuppressWarnings("unchecked")
		public boolean importData(TransferSupport support) {
			if (!canImport(support)) {
				return false;
			}

			Transferable t = support.getTransferable();
			List<File> files = null;
			try {
				files = (List<File>) t.getTransferData(DataFlavor.javaFileListFlavor);
			} catch (UnsupportedFlavorException | IOException e1) {
				// TODO Auto-generated catch block
				e1.printStackTrace();
			}

			for (File file : files) {
				String path = file.getAbsolutePath();
				model.addRow(new String[]{path, "calculating..."});
				ModelUpdater mu = new ModelUpdater(path, model.getRowCount()-1);
				mu.execute();
			}

			return true;
		}
	}

	private class ModelUpdater extends SwingWorker<String, Long> {
		private String path;
		private Integer rowindex;

		public ModelUpdater(String path, Integer rowindex) {
			this.path = path;
			this.rowindex = rowindex;
		}

		@Override
		public String doInBackground() throws IOException {
			MessageDigest md = null;
			try {
				md = MessageDigest.getInstance("SHA-1");
			} catch (NoSuchAlgorithmException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}

			// update digest with each 8MB chunk
			long totalBytes = (new File(path)).length();
			long currentBytes = 0;
			try (FileInputStream istream = new FileInputStream(path)) {
				byte[] buf = new byte[8*1024*1024];
				int n;
				while ((n = istream.read(buf, 0, buf.length)) != -1) {
					md.update(Arrays.copyOf(buf, n));
					currentBytes += n;
					publish(100*currentBytes/totalBytes);
				}
			} catch (IOException e) {
				e.printStackTrace();
			}

			byte[] digest = md.digest();
			StringBuilder sb = new StringBuilder();
			for (byte b : digest) {
				sb.append(String.format("%02x", b));
			}
			return sb.toString();
		}

		@Override
		protected void process(List<Long> values) {
			// only last one is effective
			String message = String.format("calculating %d%%...", values.get(values.size()-1));
			model.setValueAt(message, rowindex, 1);
		}

		@Override
		protected void done() {
			try {
				model.setValueAt(get(), rowindex, 1);
			} catch (Exception ignore) {
			}
		}
	}

}