public final class RangingToken
- Object
- RangingToken
The handle one device publishes so another can range against it.
A token is opaque and platform-specific. On iOS it wraps an archived
NIDiscoveryToken; on Android it carries the controller’s UWB address,
complex channel, session id and session key. There is no cross-platform
UWB ranging on either OS, so a token is never portable between them –
fromByteArray rejects a token minted by a different platform with a
clear failure rather than handing garbage to a native call.
What the token is for is the out-of-band exchange both platforms
require: prepare a session, publish toByteArray() over some other
channel the two devices already share – a GATT characteristic from
com.codename1.bluetooth is the usual one – and feed what comes back
into RangingSession.start.
byte[] mine = session.getLocalToken().toByteArray();
characteristic.writeValue(mine);
// ... later, when the peer's token arrives ...
session.start(RangingToken.fromByteArray(theirs));
Fields
public static final int PLATFORM_APPLE_NI = 1 | Token minted by Apple’s Nearby Interaction, wrapping an archived NIDiscoveryToken. |
public static final int PLATFORM_ANDROID_UWB = 2 | Token minted by the Android UWB stack, carrying address, channel, session id and key. |
public static final int PLATFORM_SIMULATED = 3 | Token minted by the simulated implementation used on the desktop ports, the simulator and the JavaScript port. |
Methods
public static RangingToken forUwbAddress(byte[] address, int channel, int preambleIndex, int sessionId, byte[] sessionKey) | Builds an Android-shaped token from parameters a third-party UWB accessory reported out of band. |
public static RangingToken fromByteArray(byte[] data) | Rebuilds a token from the bytes toByteArray() produced, typically after they travelled to this device over Bluetooth. |
public byte[] toByteArray() | The encoded form to hand to the peer. |
public int getPlatform() | Which platform minted this token – one of PLATFORM_APPLE_NI, PLATFORM_ANDROID_UWB or PLATFORM_SIMULATED. |
public boolean equals(Object o) | Indicates whether some other object is “equal to” this one. |
public int hashCode() | Returns a hash code value for the object. |
public String toString() | Returns a string representation of the object. |
Inherited methods
Field details
PLATFORM_APPLE_NI
public static final int PLATFORM_APPLE_NI = 1Token minted by Apple’s Nearby Interaction, wrapping an archived
NIDiscoveryToken.PLATFORM_ANDROID_UWB
public static final int PLATFORM_ANDROID_UWB = 2Token minted by the Android UWB stack, carrying address, channel,
session id and key.
PLATFORM_SIMULATED
public static final int PLATFORM_SIMULATED = 3Token minted by the simulated implementation used on the desktop
ports, the simulator and the JavaScript port.
Method details
forUwbAddress
public static RangingToken forUwbAddress(byte[] address, int channel, int preambleIndex, int sessionId, byte[] sessionKey)Builds an Android-shaped token from parameters a third-party UWB accessory reported out of band.
Android has no equivalent of Apple’s Nearby Interaction Accessory
Protocol, so an accessory there simply tells the phone which channel
and session to join and the phone joins it – that is what this
builds. On iOS, use RangingSession.startAccessory with the
accessory’s configuration data instead; a token built here is
rejected there.
Parameters
addressbyte[]- the accessory’s UWB MAC address, 2 or 8 bytes
channelint- the UWB channel number
preambleIndexint- the preamble index that goes with the channel
sessionIdint- the session id both ends agreed on
sessionKeybyte[]- the session key, or
nullfor an unprovisioned session
Returns
a token that
RangingSession.start accepts on AndroidfromByteArray
public static RangingToken fromByteArray(byte[] data)Rebuilds a token from the bytes
toByteArray() produced, typically
after they travelled to this device over Bluetooth.Parameters
databyte[]- the encoded token
Returns
the decoded token
Throws
IllegalArgumentException- if the bytes are not a Codename One ranging token, or carry a version this build does not understand
toByteArray
public byte[] toByteArray()The encoded form to hand to the peer. Self-describing, so the
receiving side can tell a corrupt or foreign token from a usable one.
Returns
a fresh byte array; mutating it does not affect this token
getPlatform
public int getPlatform()Which platform minted this token – one of
PLATFORM_APPLE_NI,
PLATFORM_ANDROID_UWB or PLATFORM_SIMULATED. Useful for telling
the user that the device they are pointing at is the wrong kind,
rather than letting the session fail with
NearbyError.INVALID_TOKEN.equals
public boolean equals(Object o)Indicates whether some other object is “equal to” this one.
The equals method implements an equivalence relation: It is reflexive: for any reference value x, x.equals(x) should return true. It is symmetric: for any reference values x and y, x.equals(y) should return true if and only if y.equals(x) returns true. It is transitive: for any reference values x, y, and z, if x.equals(y) returns true and y.equals(z) returns true, then x.equals(z) should return true. It is consistent: for any reference values x and y, multiple invocations of x.equals(y) consistently return true or consistently return false, provided no information used in equals comparisons on the object is modified. For any non-null reference value x, x.equals(null) should return false.
The equals method for class Object implements the most discriminating possible equivalence relation on objects; that is, for any reference values x and y, this method returns true if and only if x and y refer to the same object (x==y has the value true).
hashCode
public int hashCode()Returns a hash code value for the object. This method is supported for the benefit of hashtables such as those provided by java.util.Hashtable.
The general contract of hashCode is: Whenever it is invoked on the same object more than once during an execution of a Java application, the hashCode method must consistently return the same integer, provided no information used in equals comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application. If two objects are equal according to the equals(Object) method, then calling the hashCode method on each of the two objects must produce the same integer result. It is not required that if two objects are unequal according to the equals(java.lang.Object) method, then calling the hashCode method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hashtables.
As much as is reasonably practical, the hashCode method defined by class Object does return distinct integers for distinct objects. (This is typically implemented by converting the internal address of the object into an integer, but this implementation technique is not required by the JavaTM programming language.)
toString
public String toString()Returns a string representation of the object. In general, the toString method returns a string that “textually represents” this object. The result should be a concise but informative representation that is easy for a person to read. It is recommended that all subclasses override this method.
The toString method for class Object returns a string consisting of the name of the class of which the object is an instance, the at-sign character `@’, and the unsigned hexadecimal representation of the hash code of the object. In other words, this method returns a string equal to the value of:
getClass().getName() + ‘@’ + Integer.toHexString(hashCode())