public final class BloodPressureMeasurement

Object
BloodPressureMeasurement

A decoded Blood Pressure Measurement, characteristic 0x2A35, or the Intermediate Cuff Pressure, 0x2A36, which shares the same layout.

Wire format

Byte 0 is a flags field:

Bit	Meaning
0	units: 0 = mmHg, 1 = kPa
1	timestamp present
2	pulse rate present
3	user id present
4	measurement status present

It is followed by three 16-bit IEEE-11073 SFLOAT values – systolic, diastolic and mean arterial pressure – then the optional fields.

Two traps

This characteristic is indicated, not notified. Its client configuration descriptor takes 0x0002. The Bluetooth layer handles that automatically, but a hand-rolled GATT client that writes 0x0001 will subscribe successfully and then never receive anything.

A cuff that fails to get a reading sends a reserved SFLOAT. Those decode to Double.NaN here, and [#parse(byte[])] returns null when the systolic or diastolic value is one, so a failed measurement can never reach your UI as 2047 mmHg.

Methods

`public static` `BloodPressureMeasurement parse(byte[] value)`	Decodes a `0x2A35` or `0x2A36` value.
`public double getSystolicMmHg()`	Systolic pressure in mmHg, converted from kPa when the device reported those.
`public double getDiastolicMmHg()`	Diastolic pressure in mmHg.
`public double getMeanArterialMmHg()`	Mean arterial pressure in mmHg, or `Double.NaN` when the device did not compute one.
`public double getPulseBpm()`	Pulse in beats per minute, or `Double.NaN` when absent.
`public boolean hasPulse()`	`true` when this reading carried a pulse.
`public int getUserId()`	The device’s user-profile index, or `-1` when absent.
`public long getTimestampMillis()`	The device’s own timestamp for this reading in epoch millis, or `-1` when absent.
`public` `String toString()`	Returns a string representation of the object.

Inherited methods

From Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait, clone

Method details

parse

public static BloodPressureMeasurement parse(byte[] value)

Decodes a 0x2A35 or 0x2A36 value.

Returns null for a malformed or truncated payload, and also when the device signalled a failed measurement through a reserved SFLOAT. Never throws.

getSystolicMmHg

public double getSystolicMmHg()

Systolic pressure in mmHg, converted from kPa when the device reported those.

getDiastolicMmHg

public double getDiastolicMmHg()

Diastolic pressure in mmHg.

getMeanArterialMmHg

public double getMeanArterialMmHg()

Mean arterial pressure in mmHg, or Double.NaN when the device did not compute one.

getPulseBpm

public double getPulseBpm()

Pulse in beats per minute, or Double.NaN when absent.

hasPulse

public boolean hasPulse()

true when this reading carried a pulse.

getUserId

public int getUserId()

The device’s user-profile index, or -1 when absent. Cuffs shared by a household use it to attribute a reading.

getTimestampMillis

public long getTimestampMillis()

The device’s own timestamp for this reading in epoch millis, or -1 when absent.

Worth preferring over the time of receipt: cuffs store readings and upload them in a burst when they next connect, so several measurements taken hours apart can arrive within a second.

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())