Package protocols.apps.canvas

Class CanvasApp

java.lang.Object

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

protocols.apps.canvas.CanvasApp

public class CanvasApp
extends pt.unl.fct.di.novasys.babel.core.GenericProtocol

The collaborative-canvas application — the top of the stack, and the only protocol a user (or experiment) drives directly. It ties the overlay layers together:

• Paint operations go out as a BroadcastRequest to the eager-push gossip protocol and come back — to everyone, including us — as BroadcastDelivery notifications. Both are the shared babel-protocols-common dissemination types. Each op is applied to a PixelCanvas under last-writer-wins, so all nodes converge.
• Snapshot sync (CanvasSyncMessage) is point-to-point over HyParView's channel: on joining, a node asks one neighbour for the current canvas so it sees existing art immediately rather than waiting for new gossip.
• Presence — this node's HyParView active view — is tracked from NeighborUp/NeighborDown and surfaced in the web UI.

Two faces: interactive and headless

With canvas.ui.enabled (default) an embedded WebUi lets a human paint and watch the canvas + neighbours. With canvas.workload.enabled the node instead paints random cells at a fixed rate from a Babel timer — no UI, no human — which is how babel-canvas-experiments drives load. Both faces funnel through doPaint(int, int, int); structured Telemetry is emitted either way.

Threading note

The web server runs on its own threads; paintFromUi(int, int, int) and stateJson() are called from there. paintFromUi only calls sendRequest (which enqueues onto Babel's event loop) and the thread-safe Telemetry; it never touches the canvas directly — the op is applied when it is delivered back through uponDeliver(pt.unl.fct.di.novasys.babel.protocols.dissemination.notifications.BroadcastDelivery, short) on the event loop. stateJson reads the PixelCanvas (synchronized) and the neighbours set (a CopyOnWriteArraySet). All other state is event-loop-only.

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

Modifier and Type	Field	Description
static final String	DEFAULT_DIGEST_INTERVAL	Default for PAR_DIGEST_INTERVAL: "5000" ms.
static final String	DEFAULT_HEIGHT	Default canvas height: "48".
static final String	DEFAULT_SNAPSHOT_SYNC	Default for PAR_SNAPSHOT_SYNC: "true".
static final String	DEFAULT_UI_ENABLED	Default for PAR_UI_ENABLED: "true".
static final String	DEFAULT_UI_OPEN	Default for PAR_UI_OPEN: "true".
static final int	DEFAULT_UI_PORT_OFFSET	Offset added to the bind port to derive the default UI port.
static final String	DEFAULT_WIDTH	Default canvas width: "48".
static final String	DEFAULT_WORKLOAD_CONTROL_FILE	Default for PAR_WORKLOAD_CONTROL_FILE: "" (empty → legacy timer mode).
static final String	DEFAULT_WORKLOAD_CONTROL_POLL_MS	Default for PAR_WORKLOAD_CONTROL_POLL_MS: "250" ms.
static final String	DEFAULT_WORKLOAD_DURATION	Default for PAR_WORKLOAD_DURATION: "0" ms.
static final String	DEFAULT_WORKLOAD_ENABLED	Default for PAR_WORKLOAD_ENABLED: "false".
static final String	DEFAULT_WORKLOAD_RATE	Default for PAR_WORKLOAD_RATE: "2" ops/s.
static final String	DEFAULT_WORKLOAD_START_DELAY	Default for PAR_WORKLOAD_START_DELAY: "5000" ms.
static final String	PAR_DIGEST_INTERVAL	Property key — period (ms) between convergence-digest telemetry lines; <= 0 disables.
static final String	PAR_HEIGHT	Property key — shared grid height in cells.
static final String	PAR_SNAPSHOT_SYNC	Property key — request a canvas snapshot from a neighbour on join.
static final String	PAR_UI_ENABLED	Property key — enable the embedded web UI.
static final String	PAR_UI_OPEN	Property key — open the system browser at the UI on startup (best-effort).
static final String	PAR_UI_PORT	Property key — web UI port.
static final String	PAR_WIDTH	Property key — shared grid width in cells.
static final String	PAR_WORKLOAD_CONTROL_FILE	Property key — shared control file (RUN/STOP) the experiment script drives; empty = legacy timer mode.
static final String	PAR_WORKLOAD_CONTROL_POLL_MS	Property key — how often (ms) to poll the control file in coordinated mode.
static final String	PAR_WORKLOAD_DURATION	Property key — how long (ms) to keep painting; <= 0 = until stopped.
static final String	PAR_WORKLOAD_ENABLED	Property key — enable the headless random-paint workload driver.
static final String	PAR_WORKLOAD_RATE	Property key — workload paint operations per second.
static final String	PAR_WORKLOAD_START_DELAY	Property key — delay (ms) before the first workload paint, to let the overlay form.
static final short	PROTO_ID
static final String	PROTO_NAME

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

babel, babelSecurity

Constructor Summary

Constructors

Constructor	Description
CanvasApp(Properties props, pt.unl.fct.di.novasys.network.data.Host myself, short broadcastProtoId, short membershipProtoId)

Method Summary

Modifier and Type	Method	Description
int	getUiPort()
void	init(Properties props)
boolean	isUiEnabled()
void	paintFromUi(int x, int y, int rgb)	Paint a cell from the web UI.
String	stateJson()	A JSON snapshot of canvas + neighbours for the web UI's polling loop.

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

Field Details

PROTO_ID

public static final short PROTO_ID

See Also:

• Constant Field Values

PROTO_NAME

public static final String PROTO_NAME

See Also:

• Constant Field Values

PAR_WIDTH

public static final String PAR_WIDTH

Property key — shared grid width in cells. Must match across all nodes.

See Also:

• Constant Field Values

DEFAULT_WIDTH

public static final String DEFAULT_WIDTH

Default canvas width: "48".

See Also:

• Constant Field Values

PAR_HEIGHT

public static final String PAR_HEIGHT

Property key — shared grid height in cells. Must match across all nodes.

See Also:

• Constant Field Values

DEFAULT_HEIGHT

public static final String DEFAULT_HEIGHT

Default canvas height: "48".

See Also:

• Constant Field Values

PAR_UI_ENABLED

public static final String PAR_UI_ENABLED

Property key — enable the embedded web UI.

See Also:

• Constant Field Values

DEFAULT_UI_ENABLED

public static final String DEFAULT_UI_ENABLED

Default for PAR_UI_ENABLED: "true".

See Also:

• Constant Field Values

PAR_UI_PORT

public static final String PAR_UI_PORT

Property key — web UI port. Defaults to babel.port + 2000 when unset.

See Also:

• Constant Field Values

DEFAULT_UI_PORT_OFFSET

public static final int DEFAULT_UI_PORT_OFFSET

Offset added to the bind port to derive the default UI port.

See Also:

• Constant Field Values

PAR_UI_OPEN

public static final String PAR_UI_OPEN

Property key — open the system browser at the UI on startup (best-effort).

See Also:

• Constant Field Values

DEFAULT_UI_OPEN

public static final String DEFAULT_UI_OPEN

Default for PAR_UI_OPEN: "true".

See Also:

• Constant Field Values

PAR_SNAPSHOT_SYNC

public static final String PAR_SNAPSHOT_SYNC

Property key — request a canvas snapshot from a neighbour on join.

See Also:

• Constant Field Values

DEFAULT_SNAPSHOT_SYNC

public static final String DEFAULT_SNAPSHOT_SYNC

Default for PAR_SNAPSHOT_SYNC: "true".

See Also:

• Constant Field Values

PAR_DIGEST_INTERVAL

public static final String PAR_DIGEST_INTERVAL

Property key — period (ms) between convergence-digest telemetry lines; <= 0 disables.

See Also:

• Constant Field Values

DEFAULT_DIGEST_INTERVAL

public static final String DEFAULT_DIGEST_INTERVAL

Default for PAR_DIGEST_INTERVAL: "5000" ms.

See Also:

• Constant Field Values

PAR_WORKLOAD_ENABLED

public static final String PAR_WORKLOAD_ENABLED

Property key — enable the headless random-paint workload driver.

See Also:

• Constant Field Values

DEFAULT_WORKLOAD_ENABLED

public static final String DEFAULT_WORKLOAD_ENABLED

Default for PAR_WORKLOAD_ENABLED: "false".

See Also:

• Constant Field Values

PAR_WORKLOAD_RATE

public static final String PAR_WORKLOAD_RATE

Property key — workload paint operations per second.

See Also:

• Constant Field Values

DEFAULT_WORKLOAD_RATE

public static final String DEFAULT_WORKLOAD_RATE

Default for PAR_WORKLOAD_RATE: "2" ops/s.

See Also:

• Constant Field Values

PAR_WORKLOAD_DURATION

public static final String PAR_WORKLOAD_DURATION

Property key — how long (ms) to keep painting; <= 0 = until stopped.

See Also:

• Constant Field Values

DEFAULT_WORKLOAD_DURATION

public static final String DEFAULT_WORKLOAD_DURATION

Default for PAR_WORKLOAD_DURATION: "0" ms.

See Also:

• Constant Field Values

PAR_WORKLOAD_START_DELAY

public static final String PAR_WORKLOAD_START_DELAY

Property key — delay (ms) before the first workload paint, to let the overlay form. Legacy/fallback path only: ignored when PAR_WORKLOAD_CONTROL_FILE is set (then the orchestrator's RUN/STOP drives start/stop).

See Also:

• Constant Field Values

DEFAULT_WORKLOAD_START_DELAY

public static final String DEFAULT_WORKLOAD_START_DELAY

Default for PAR_WORKLOAD_START_DELAY: "5000" ms.

See Also:

• Constant Field Values

PAR_WORKLOAD_CONTROL_FILE

public static final String PAR_WORKLOAD_CONTROL_FILE

Property key — shared control file (RUN/STOP) the experiment script drives; empty = legacy timer mode.

See Also:

• Constant Field Values

DEFAULT_WORKLOAD_CONTROL_FILE

public static final String DEFAULT_WORKLOAD_CONTROL_FILE

Default for PAR_WORKLOAD_CONTROL_FILE: "" (empty → legacy timer mode).

See Also:

• Constant Field Values

PAR_WORKLOAD_CONTROL_POLL_MS

public static final String PAR_WORKLOAD_CONTROL_POLL_MS

Property key — how often (ms) to poll the control file in coordinated mode.

See Also:

• Constant Field Values

DEFAULT_WORKLOAD_CONTROL_POLL_MS

public static final String DEFAULT_WORKLOAD_CONTROL_POLL_MS

Default for PAR_WORKLOAD_CONTROL_POLL_MS: "250" ms.

See Also:

• Constant Field Values

Constructor Details

CanvasApp

public CanvasApp(Properties props,
 pt.unl.fct.di.novasys.network.data.Host myself,
 short broadcastProtoId,
 short membershipProtoId)
          throws pt.unl.fct.di.novasys.babel.exceptions.HandlerRegistrationException,
IOException

Parameters:

props - protocol configuration; see the PAR_* constants

myself - this node's membership-space Host (HyParView's bind endpoint)

broadcastProtoId - the eager-push gossip protocol id (paint ops are sent there)

membershipProtoId - the HyParView protocol id (its channel is reused for snapshot sync)

Throws:

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

IOException

Method Details

init

public void init(Properties props)

Specified by:

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

paintFromUi

public void paintFromUi(int x,
 int y,
 int rgb)

Paint a cell from the web UI. rgb is a 24-bit colour (0xRRGGBB); we force it opaque. Safe to call from the web-server thread (see the class threading note).

stateJson

public String stateJson()

A JSON snapshot of canvas + neighbours for the web UI's polling loop.

getUiPort

public int getUiPort()

isUiEnabled

public boolean isUiEnabled()