Package edu.cnu.mdi.splot.pdata

Class StripChartCurve

java.lang.Object

edu.cnu.mdi.splot.pdata.ACurve

edu.cnu.mdi.splot.pdata.StripChartCurve

public class StripChartCurve
extends ACurve

Backing data model for a strip chart / time-series plot.

This class periodically samples a provided Evaluator and appends (t, y) points into bounded X and Y columns. When capacity is reached, the oldest samples are dropped ("scrolls off the left").

Threading

Sampling runs on a background scheduler thread. To preserve the ACurve contract that notifications occur on the Swing Event Dispatch Thread (EDT), this class uses a lock-free staging queue:

• The background sampler thread computes samples and enqueues them.
• An EDT drain pass applies samples in bounded batches under ACurve.lock.
• A single consolidated ACurve.markDataChanged() is fired per batch (EDT-only).

The optional setOnSample(Runnable) callback, if provided, is invoked on the EDT after each drain pass. This is a convenient place to call repaint() safely.

Nested Class Summary

Nested classes/interfaces inherited from class edu.cnu.mdi.splot.pdata.ACurve

ACurve.PendingQueue<T>

Field Summary

Fields inherited from class edu.cnu.mdi.splot.pdata.ACurve

lock

Constructor Summary

Constructors

Constructor	Description
StripChartCurve(String name, int capacity, Evaluator accumulator, long intervalMs)	Create strip-chart data.

Method Summary

Modifier and Type	Method	Description
void	add(double tms, double y)	Add an explicit sample (t, y) to this strip chart.
void	clearData()	Clear all retained samples.
void	doFit(boolean force)	Perform a curve computation (fit or spline) on the strip chart's current data, depending on the configured CurveDrawingMethod.
int	getCapacity()
long	getIntervalMs()
TimeUnit	getTimeUnit()
String	getTimeUnitShortLabel()	A short label you can use in axis titles ("Time (s)", etc.).
boolean	isRunning()
int	length()	Get curve length (number of points or effective points in the data columns).
void	setCapacity(int capacity)	Set the capacity (max samples retained).
void	setIntervalMs(long intervalMs)	Set the sampling interval.
void	setOnSample(Runnable onSample)	Set a callback to be invoked after each drain pass on the EDT.
void	setTimeUnit(TimeUnit unit)	Set the display unit for the time axis.
void	shutdown()	Permanently shut down this StripChartCurve (cannot be restarted).
Snapshot	snapshot()	Obtain a consistent snapshot of the current data, suitable for plotting without locking.
void	start()	Start sampling.
void	stop()	Stop sampling.
double	xMax()
double	xMin()
double	yMax()
double	yMin()

Methods inherited from class edu.cnu.mdi.splot.pdata.ACurve

addCurveChangeListener, beginUpdate, createFitterForCurrentMethod, dataChanged, endUpdate, fireCurveChanged, fitResult, fitWithOptionalWeights, getCubicSpline, getCurveDrawingMethod, getFitOrder, getFitSummary, getFitValueGetter, getStyle, initStyle, isDirty, isHistogram, isStripChart, isVisible, isXYCurve, markDataChanged, markFitChanged, markStyleChanged, name, removeCurveChangeListener, requireEdt, scheduleDrainOnce, setCubicSpline, setCurveDrawingMethod, setDirty, setFitOrder, setFitResult, setName, setStyle, setVisible, styleChanged, toString

Methods inherited from class java.lang.Object

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

Constructor Details

StripChartCurve

public StripChartCurve(String name,
 int capacity,
 Evaluator accumulator,
 long intervalMs)

Create strip-chart data.

Parameters:

name - series name

capacity - max number of retained samples (>= 2)

accumulator - value source; called as accumulator.value(tMs) (non-null)

intervalMs - update interval in milliseconds (> 0)

Method Details

getCapacity

public int getCapacity()

Returns:

current capacity (max samples retained).

setCapacity

public void setCapacity(int capacity)

Set the capacity (max samples retained). If the current size exceeds the new capacity, oldest samples are dropped immediately.

If called off the EDT, this method schedules the capacity enforcement on the EDT to keep column mutation and notifications Swing-correct.

Parameters:

capacity - must be >= 2

getIntervalMs

public long getIntervalMs()

Returns:

sampling interval in milliseconds.

getTimeUnit

public TimeUnit getTimeUnit()

Returns:

the current display unit for time on the x-axis.

setTimeUnit

public void setTimeUnit(TimeUnit unit)

Set the display unit for the time axis.

Internal storage remains milliseconds; snapshot/min/max are scaled. This triggers a data change notification so axes/ticks update.

Parameters:

unit - non-null

getTimeUnitShortLabel

public String getTimeUnitShortLabel()

A short label you can use in axis titles ("Time (s)", etc.).

setIntervalMs

public void setIntervalMs(long intervalMs)

Set the sampling interval. If currently running, restarts the schedule.

Parameters:

intervalMs - must be > 0

setOnSample

public void setOnSample(Runnable onSample)

Set a callback to be invoked after each drain pass on the EDT.

This is a convenient place to call repaint() without additional SwingUtilities.invokeLater(...).

Parameters:

onSample - may be null

isRunning

public boolean isRunning()

Returns:

true if actively sampling.

start

public void start()

Start sampling. Safe to call multiple times; subsequent calls do nothing if already running.

stop

public void stop()

Stop sampling. Safe to call multiple times.

This cancels the scheduled task but keeps the scheduler alive so you can start() again.

shutdown

public void shutdown()

Permanently shut down this StripChartCurve (cannot be restarted). Use when the owning plot is being disposed.

clearData

public void clearData()

Clear all retained samples.

Thread-safe: if called off-EDT, schedules the clear on the EDT. Pending queued samples are also discarded so the curve becomes truly empty.

Specified by:

clearData in class ACurve

snapshot

public Snapshot snapshot()

Obtain a consistent snapshot of the current data, suitable for plotting without locking.

Specified by:

snapshot in class ACurve

Returns:

snapshot containing primitive arrays of x and y data. Those arrays are copies of the internal data at the moment of the snapshot.

add

public void add(double tms,
 double y)

Add an explicit sample (t, y) to this strip chart.

Thread-safe: may be called from any thread. Off-EDT calls enqueue and schedule a coalesced EDT drain. Notifications remain EDT-only per ACurve.

Parameters:

tms - time value (typically ms since start)

y - sample value

doFit

public void doFit(boolean force)

Perform a curve computation (fit or spline) on the strip chart's current data, depending on the configured CurveDrawingMethod.

Same dispatch as Curve.doFit(boolean): CUBICSPLINE builds a CubicSpline, the parametric methods (POLYNOMIAL, ERF, ERFC, GAUSSIAN, GAUSSIANS, EXPONENTIAL_DECAY, POWER_LAW, LORENTZIAN) run the corresponding IFitter, and NONE/CONNECT/STAIRS require no computed artifact. Must be called on the EDT.

Specified by:

doFit in class ACurve

Parameters:

force - true to force recomputation even if not dirty

length

public int length()

Description copied from class: ACurve

Get curve length (number of points or effective points in the data columns).

Specified by:

length in class ACurve

Returns:

curve length

xMin

public double xMin()

Specified by:

xMin in class ACurve

Returns:

the minimum x value for this curve

xMax

public double xMax()

Specified by:

xMax in class ACurve

Returns:

the maximum x value for this curve

yMin

public double yMin()

Specified by:

yMin in class ACurve

Returns:

the minimum y value for this curve

yMax

public double yMax()

Specified by:

yMax in class ACurve

Returns:

the maximum y value for this curve