Package pt.unl.fct.di.tardis.babel.iot.demos

Class BabelAnyGestureMatrixDemo

java.lang.Object

pt.unl.fct.di.novasys.babel.core.GenericProtocol

pt.unl.fct.di.tardis.babel.iot.demos.BabelAnyGestureMatrixDemo

All Implemented Interfaces:

BabelDemo

public class BabelAnyGestureMatrixDemo
extends pt.unl.fct.di.novasys.babel.core.GenericProtocol
implements BabelDemo

Reactive Babel demo: shows an emoji on the Grove RGB LED matrix for any gesture the detector reports.

This is a textbook example of reactive input driving output: one input device asynchronously notifies the application, which then commands an output device. It wires together two of the IoT control protocols:

• I2CInputControlProtocol (id 2100) reads the Grove gesture detector and, once asked for "reactive" gestures, emits a GestureNotification every time a hand movement is recognised.
• I2COutputControlProtocol (id 2000) drives the Grove RGB LED matrix; the demo sends it a ShowEmojiRequest carrying the matrix's DeviceHandle whenever a gesture arrives.

The demo itself is a GenericProtocol: it never touches Pi4J, I²C or any GPIO line directly. It only exchanges Babel requests/replies/notifications with the control protocols, which own the hardware. This is the same "Pattern 1: driving a Grove device" flow documented in the module README.md, plus a notification subscription for the reactive input.

Run it with the command-line name anyGesture (see Main.java):

java -jar babel-raspberry-iot-examples.jar anyGesture

See Also:

• the fully-commented output-only exemplar in this package

Nested Class Summary

Nested classes/interfaces inherited from class pt.unl.fct.di.novasys.babel.core.GenericProtocol

pt.unl.fct.di.novasys.babel.core.GenericProtocol.ProtocolMetricsBabelMetrics

Field Summary

Fields inherited from class pt.unl.fct.di.novasys.babel.core.GenericProtocol

babel, babelSecurity

Fields inherited from interface pt.unl.fct.di.tardis.babel.iot.demos.BabelDemo

PROTO_ID, PROTO_NAME

Constructor Summary

Constructors

Constructor	Description
BabelAnyGestureMatrixDemo()	Builds the demo protocol.

Method Summary

Modifier and Type	Method	Description
void	execute()	Application entry point (invoked by Main for the anyGesture demo).
void	handleDemoTimer(DemoTimer t, long time)	Timer handler driven by the periodic DemoTimer armed above.
void	handleGestureInputReply(pt.unl.fct.di.tardis.babel.iot.controlprotocols.replies.GestureInputReply rep, short protocolId)	Reply handler for the GetReactiveGestureRequest we sent to arm the detector.
void	handleRegisterIoTDeviceReply(pt.unl.fct.di.tardis.babel.iot.api.replies.RegisterIoTDeviceReply rep, short protocolId)	Reply handler for RegisterIoTDeviceReply.
void	init(Properties props)	Babel lifecycle hook: register every handler this protocol needs, then kick off the work.

Methods inherited from class pt.unl.fct.di.novasys.babel.core.GenericProtocol

addSecret, addSecret, addSecret, addSecret, cancelTimer, closeConnection, closeConnection, closeConnection, closeConnection, closeConnection, closeConnection, createChannel, createSecureChannel, createSecureChannel, createSecureChannel, createSecureChannelWithAliases, createSecureChannelWithAliases, createSecureChannelWithIdentities, createSecureChannelWithIdentities, createSecureChannelWithProtoIdentities, enableGenericMetrics, generateIdentity, generateIdentity, generateIdentity, generateIdentity, generateIdentity, generateIdentity, generateIdentity, generateSecret, generateSecret, generateSecret, generateSecret, generateSecretFromPassword, generateSecretFromPassword, generateSecretFromPassword, generateSecretFromPassword, getChannelOrThrow, getDefaultChannel, getDefaultProtoIdentity, getDefaultProtoIdentityCrypt, getDefaultProtoSecret, getMillisSinceBabelStart, getOrGenerateDefaultProtoIdentity, getProtoId, getProtoName, hasProtocolThreadStarted, openConnection, openConnection, openConnection, openConnection, registerChannelEventHandler, registerMessageHandler, registerMessageHandler, registerMessageHandler, registerMessageHandler, registerMessageHandler, registerMessageHandler, registerMessageHandler, registerMessageHandler, registerMessageHandler, registerMessageHandler, registerMessageHandler, registerMessageHandler, registerMessageHandler, registerMessageHandler, registerMessageHandler, registerMessageHandler, registerMessageHandler, registerMessageHandler, registerMessageSerializer, registerMetric, registerReplyHandler, registerRequestHandler, registerSharedChannel, registerTimerHandler, sendMessage, sendMessage, sendMessage, sendMessage, sendMessage, sendMessage, sendMessage, sendMessage, sendMessage, sendMessage, sendMessage, sendMessage, sendMessage, sendMessage, sendReply, sendRequest, setDefaultChannel, setDefaultProtoIdentity, setDefaultProtoIdentity, setDefaultProtoSecret, setupPeriodicTimer, setupTimer, startEventThread, subscribeNotification, triggerNotification, unsubscribeNotification

Methods inherited from class java.lang.Object

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

Constructor Details

BabelAnyGestureMatrixDemo

public BabelAnyGestureMatrixDemo()

Builds the demo protocol. Like every Babel GenericProtocol, it must declare a protocol name and a globally unique protocol id (here the shared BabelDemo constants); Babel uses the id to route events to this instance.

Method Details

init

public void init(Properties props)
          throws pt.unl.fct.di.novasys.babel.exceptions.HandlerRegistrationException,
IOException

Babel lifecycle hook: register every handler this protocol needs, then kick off the work. The golden rule is to register handlers BEFORE sending the request that triggers them, otherwise the reply/notification could arrive before there is anyone to receive it.

Specified by:

init in class pt.unl.fct.di.novasys.babel.core.GenericProtocol

Throws:

pt.unl.fct.di.novasys.babel.exceptions.HandlerRegistrationException

IOException

handleRegisterIoTDeviceReply

public void handleRegisterIoTDeviceReply(pt.unl.fct.di.tardis.babel.iot.api.replies.RegisterIoTDeviceReply rep,
 short protocolId)

Reply handler for RegisterIoTDeviceReply. Babel calls it once for each RegisterIoTDeviceRequest we sent — here twice, one per device. The canonical pattern is: check RegisterIoTDeviceReply.isSuccessful(), and on success keep the DeviceHandle. Because both registrations share this one handler, we branch on the reply's device type to store the right handle.

handleGestureInputReply

public void handleGestureInputReply(pt.unl.fct.di.tardis.babel.iot.controlprotocols.replies.GestureInputReply rep,
 short protocolId)

Reply handler for the GetReactiveGestureRequest we sent to arm the detector. It confirms the input protocol accepted the reactive subscription; on success the demo paints the matrix blue as a visible "ready" acknowledgement. The actual per-gesture reaction happens later in handleGestureNotification(pt.unl.fct.di.tardis.babel.iot.controlprotocols.notifications.GestureNotification, short).

handleDemoTimer

public void handleDemoTimer(DemoTimer t,
 long time)

Timer handler driven by the periodic DemoTimer armed above. Each tick repaints the matrix green, giving the display a steady "idle" colour in between gesture-triggered emojis. Shows how a Babel protocol mixes timer-driven and event-driven work in the same single-threaded handler model.

execute

public void execute()
             throws Exception

Application entry point (invoked by Main for the anyGesture demo). It performs the standard Babel bootstrap:

1. get the singleton Babel instance;
2. load configuration from paradigmshift.config;
3. instantiate the control protocols this demo depends on (I²C output 2000 + I²C input 2100) and the demo protocol itself;
4. registerProtocol each one with Babel;
5. init them in dependency order — the control protocols first, then the demo, so the targets of the demo's first requests already exist;
6. start Babel, which spins up the event loops and begins delivering events to the registered handlers.

Note the demo wires hardware access entirely through these protocols: it never constructs a Pi4J context or opens an I²C bus itself.

Specified by:

execute in interface BabelDemo

Throws:

Exception