#385

/**
 * Generate a hash for a file.
 */
public final class HashUtils {

    /** Default hash algorithm. */
    public static final Algo DEFAULT_ALGO = Algo.MD5;

    /**
     * Define all hash algorithm.
     */
    public enum Algo {
        /** MD5. */
        MD5("MD5"),
        /** SHA1. */
        SHA1("SHA-1"),
        /** SHA256. */
        SHA256("SHA-256"),
        /** SHA384. */
        SHA384("SHA-384"),
        /** SHA512. */
        SHA512("SHA-512");

        private String value;

        /**
         * Default constructor.
         * 
         * @param name
         *            of the algo
         */
        Algo(final String name) {
            value = name;
        }

        /**
         * @return the value
         */
        String getValue() {
            return value;
        }

        /**
         * Set the value.
         * 
         * @param name
         *            of the value to set
         */
        void setValue(final String name) {
            value = name;
        }
    };

    /**
     * Default private constructor.
     */
    private HashUtils() {

    }

    /**
     * Return hash representation of the file content. (using default algorithm)
     * 
     * @param filename
     *            name of the file to hash
     * @return hash representation of the file
     * @throws Exception
     *             in case of error
     */
    public static String getChecksum(final String filename) throws Exception {
        return getChecksum(filename, DEFAULT_ALGO);
    }

    /**
     * Return hash representation of the file content. (using specific algorithm)
     * 
     * @param filename
     *            name of the file to hash
     * @param algo
     *            used to hash the file
     * @return hash representation of the file
     * @throws Exception
     *             in case of error
     */
    public static String getChecksum(final String filename, final Algo algo) throws Exception {
        byte[] b = createChecksum(filename, algo);
        String result = "";
        for (int i = 0; i < b.length; i++) {
            result += Integer.toString((b[i] & 0xff) + 0x100, 16).substring(1);
        }

        return result;
    }

    /**
     * Read and parse file to hash.
     * 
     * @param filename
     *            name of the file to hash
     * @param algo
     *            used to hash the file
     * @return byte array representing hash
     * @throws Exception
     *             in case of error
     */
    private static byte[] createChecksum(final String filename, final Algo algo) throws Exception {
        InputStream fis = new FileInputStream(filename);
        byte[] buffer = new byte[1024];
        MessageDigest complete = MessageDigest.getInstance(algo.getValue());
        int numRead;
        do {
            numRead = fis.read(buffer);
            if (numRead > 0) {
                complete.update(buffer, 0, numRead);
            }
        } while (numRead != -1);
        fis.close();
        return complete.digest();
    }
}

java

[Solaris] Restart service [PL/SQL] SQL Query over function