ONOS-3655 - Adding username and password support into the device key subsystem.

Change-Id: I196984479126ae3776093a0bded4b3c820a3eab8
diff --git a/incubator/api/src/main/java/org/onosproject/incubator/net/key/UsernamePassword.java b/incubator/api/src/main/java/org/onosproject/incubator/net/key/UsernamePassword.java
new file mode 100644
index 0000000..e3ca1fb
--- /dev/null
+++ b/incubator/api/src/main/java/org/onosproject/incubator/net/key/UsernamePassword.java
@@ -0,0 +1,65 @@
+/*
+ * Copyright 2016 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.onosproject.incubator.net.key;
+
+/**
+ * Representation of a username and password.
+ */
+public final class UsernamePassword extends DeviceKey {
+    private final String username;
+    private final String password;
+
+    /**
+     * Private constructor for a username and password.
+     *
+     * @param username user's name
+     * @param password user's password
+     */
+    private UsernamePassword(String username, String password) {
+        this.username = username;
+        this.password = password;
+    }
+
+    /**
+     * Static method to construct a username / password.
+     *
+     * @param username user's name
+     * @param password user's password
+     * @return username and password
+     */
+    static UsernamePassword usernamePassword(String username, String password) {
+        return new UsernamePassword(username, password);
+    }
+
+    /**
+     * Returns the username.
+     *
+     * @return username
+     */
+    public String username() {
+        return username;
+    }
+
+    /**
+     * Returns the password.
+     *
+     * @return password
+     */
+    public String password() {
+        return password;
+    }
+}