Added LoginCredentials, moved SerializationUtils to envoy-common

src/main/java/envoy/data/LoginCredentials.java

@@ -0,0 +1,59 @@
+package envoy.data;
+
+import java.io.Serializable;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+
+/**
+ * Project: <strong>envoy-common</strong><br>
+ * File: <strong>LoginCredentials.java</strong><br>
+ * Created: <strong>29.12.2019</strong><br>
+ * 
+ * @author Kai S. K. Engelbart
+ * @since Envoy Common v0.2-alpha
+ */
+public class LoginCredentials implements Serializable {
+
+	private final String	name;
+	private final byte[]	passwordHash;
+
+	private static final long serialVersionUID = -7395245059059523314L;
+
+	/**
+	 * Creates an in stance of {@link LoginCredentials}.
+	 * 
+	 * @param name     the name of the user
+	 * @param password the password of the user (will be converted to a hash)
+	 * @throws NoSuchAlgorithmException
+	 */
+	public LoginCredentials(String name, char[] password) throws NoSuchAlgorithmException {
+		this.name		= name;
+		passwordHash	= getSha256(toByteArray(password));
+	}
+
+	private byte[] toByteArray(char[] chars) {
+		byte[] bytes = new byte[chars.length * 2];
+		for (int i = 0; i < chars.length; ++i) {
+			bytes[i * 2]		= (byte) (chars[i] >> 8);
+			bytes[i * 2 + 1]	= (byte) (chars[i]);
+		}
+		return bytes;
+	}
+
+	private byte[] getSha256(byte[] input) throws NoSuchAlgorithmException {
+		MessageDigest md = MessageDigest.getInstance("SHA-256");
+		return md.digest(input);
+	}
+
+	/**
+	 * @return the name of the user performing the login
+	 * @since Envoy Common v0.2-alpha
+	 */
+	public String getName() { return name; }
+
+	/**
+	 * @return the password hash of the user performing the login
+	 * @since Envoy Common v0.2-alpha
+	 */
+	public byte[] getPasswordHash() { return passwordHash; }
+}

src/main/java/envoy/util/SerializationUtils.java

@@ -0,0 +1,91 @@
+package envoy.util;
+
+import java.io.ByteArrayOutputStream;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+import java.io.OutputStream;
+import java.io.Serializable;
+
+import envoy.exception.EnvoyException;
+
+/**
+ * Project: <strong>envoy-client</strong><br>
+ * File: <strong>SerializationUtils.java</strong><br>
+ * Created: <strong>23.12.2019</strong><br>
+ * 
+ * @author Kai S. K. Engelbart
+ * @since Envoy Common v0.2-alpha
+ */
+public class SerializationUtils {
+
+	private SerializationUtils() {}
+
+	/**
+	 * Deserializes an arbitrary {@link Serializable} object from a file.
+	 * 
+	 * @param <T>             the type of the object to deserialize
+	 * @param file            the file deserialize from
+	 * @param serializedClass the class of the object to deserialize
+	 * @return the deserialized object
+	 * @throws EnvoyException if an error occurred during deserialization
+	 * @since Envoy Common v0.2-alpha
+	 */
+	public static <T extends Serializable> T read(File file, Class<T> serializedClass) throws EnvoyException {
+		if (file == null) throw new NullPointerException("File is null");
+		try (ObjectInputStream in = new ObjectInputStream(new FileInputStream(file))) {
+			return serializedClass.cast(in.readObject());
+		} catch (ClassNotFoundException | IOException e) {
+			throw new EnvoyException("Could not load serialized object", e);
+		}
+	}
+
+	/**
+	 * Serializes an arbitrary object to a file.
+	 * 
+	 * @param file the file to serialize to
+	 * @param obj  the object to serialize
+	 * @throws IOException if an error occurred during serialization
+	 * @since Envoy Common v0.2-alpha
+	 */
+	public static void write(File file, Object obj) throws IOException {
+		if (file == null) throw new NullPointerException("File is null");
+		if (obj == null) throw new NullPointerException("Object to serialize is null");
+		if (!file.exists()) {
+			file.getParentFile().mkdirs();
+			file.createNewFile();
+		}
+		try (ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream(file))) {
+			out.writeObject(obj);
+		}
+	}
+
+	/**
+	 * Serializes an object and writes it into an output stream preceded by 4 bytes
+	 * containing the number of serialized bytes.
+	 * 
+	 * @param obj the object to serialize
+	 * @param out the output stream to serialize to
+	 * @throws IOException if an error occurred during serialization
+	 */
+	public static void writeBytesWithLength(Object obj, OutputStream out) throws IOException {
+		// Serialize object to byte array
+		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		try (ObjectOutputStream oout = new ObjectOutputStream(baos)) {
+			oout.writeObject(obj);
+		}
+		byte[] objBytes = baos.toByteArray();
+
+		// Get length of byte array in bytes
+		byte[] objLen = getBytes(objBytes.length);
+
+		// Write length and byte array
+		out.write(objLen);
+		out.write(objBytes);
+	}
+
+	private static byte[] getBytes(int n) { return new byte[] { (byte) (n >>> 24), (byte) (n >>> 16), (byte) (n >>> 8) }; }
+}