cleaning up constants

components/device-mgt/org.wso2.carbon.device.mgt.mobile.impl/src/main/java/org/wso2/carbon/device/mgt/mobile/impl/MobileDeviceManagementConstants.java

@@ -19,10 +19,15 @@ package org.wso2.carbon.device.mgt.mobile.impl;
 /**
  * Constants used by Mobile device Management classes.
  */
-public class MobileDeviceManagementConstants {
+public final class MobileDeviceManagementConstants {
 
+    public static class PlatformTypes {
+        private PlatformTypes() {
+            throw new AssertionError();
+        }
         public final static String MOBILE_DEVICE_TYPE_ANDROID = "android";
         public final static String MOBILE_DEVICE_TYPE_IOS = "ios";
         public final static String MOBILE_DEVICE_TYPE_WINDOWS = "windows";
+    }
 
 }

components/device-mgt/org.wso2.carbon.device.mgt.mobile.impl/src/main/java/org/wso2/carbon/device/mgt/mobile/impl/android/AndroidDeviceManagerService.java

@@ -31,7 +31,7 @@ public class AndroidDeviceManagerService implements DeviceManagerService {
 
 	@Override
 	public String getProviderType() {
-		return MobileDeviceManagementConstants.MOBILE_DEVICE_TYPE_ANDROID;
+		return MobileDeviceManagementConstants.PlatformTypes.MOBILE_DEVICE_TYPE_ANDROID;
 	}
 
 	@Override

components/device-mgt/org.wso2.carbon.device.mgt.mobile.impl/src/main/java/org/wso2/carbon/device/mgt/mobile/impl/ios/IOSDeviceManagerService.java

@@ -31,7 +31,7 @@ public class IOSDeviceManagerService implements DeviceManagerService {
 
     @Override
     public String getProviderType() {
-        return MobileDeviceManagementConstants.MOBILE_DEVICE_TYPE_IOS;
+        return MobileDeviceManagementConstants.PlatformTypes.MOBILE_DEVICE_TYPE_IOS;
     }
 
     @Override

components/device-mgt/org.wso2.carbon.device.mgt.mobile.impl/src/main/java/org/wso2/carbon/device/mgt/mobile/impl/windows/WindowsDeviceManagerService.java

@@ -31,7 +31,7 @@ public class WindowsDeviceManagerService implements DeviceManagerService {
 
     @Override
     public String getProviderType() {
-        return MobileDeviceManagementConstants.MOBILE_DEVICE_TYPE_WINDOWS;
+        return MobileDeviceManagementConstants.PlatformTypes.MOBILE_DEVICE_TYPE_WINDOWS;
     }
 
     @Override