org.cybergarage.upnp.device

## Class USN

- java.lang.Object
- - org.cybergarage.upnp.device.USN

-     public class USN
      extends Object

  Utility class for SSDP USN (Unique Service Name) header values and parsing.

  This class provides constants and utility methods for handling USN header used in SSDP messages. The USN header provides a unique identifier for devices and services in UPnP networks.

  Key features:

  - Root device USN validation
  - UDN (Unique Device Name) extraction
  - USN parsing and manipulation
  - UTF-8 encoding support
  - Null-safe value handling

  This class is used by SSDP components to parse and validate USN headers in discovery and advertisement messages, enabling proper device identification and service differentiation in UPnP networks.

- - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `static String` | `ROOTDEVICE`

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `USN()`

  - ### Method Summary

    All Methods Static Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `static String` | `getUDN(String usnValue)`
    `static boolean` | `isRootDevice(String usnValue)`

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### Field Detail

    - #### ROOTDEVICE

          public static final String ROOTDEVICE

      See Also:
        Constant Field Values

  - ### Constructor Detail

    - #### USN

          public USN()

  - ### Method Detail

    - #### getUDN

          public static final String getUDN(String usnValue)

    - #### isRootDevice

          public static final boolean isRootDevice(String usnValue)