Class OnChangeRTIndicator

java.lang.Object

com.wualabs.qtsurfer.engine.indicators.core.AbstractRTIndicator

com.wualabs.qtsurfer.engine.indicators.core.AbstractIncrementalRTIndicator

com.wualabs.qtsurfer.engine.indicators.core.AbstractDecorableIncrementalRTIndicator

com.wualabs.qtsurfer.engine.indicators.helpers.OnChangeRTIndicator

All Implemented Interfaces:

ClockAware, Resettable, RTIndicator

Direct Known Subclasses:

WindowTimeRTIndicator

public class OnChangeRTIndicator
extends AbstractDecorableIncrementalRTIndicator

Incremental indicator that fires change notifications to registered listeners whenever its value changes. Its StateStore is pluggable — see setStateStoreSupplier(Supplier) — and is only materialized when a listener is actually there to receive it. Events can be disabled via setEnableEvents(boolean).

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	OnChangeRTIndicator.OnChangeListener

Constructor Summary

Constructors

Constructor	Description
OnChangeRTIndicator()
OnChangeRTIndicator(RTIndicator indicator)

Method Summary

Modifier and Type	Method	Description
void	addOnChangeListener(OnChangeRTIndicator.OnChangeListener listener)
void	clearOnChangeListeners()
StateStore	getStateStore()	Resolves this indicator's state store: the externally supplied one if setStateStoreSupplier(Supplier) was called, otherwise a private in-memory store created on demand.
protected boolean	hasListeners()
boolean	isEnableEvents()
protected double	nextValue(double prevValue, double newValue)	Fires change notifications (if events are enabled) before delegating to the parent's nextValue computation.
protected void	notifyOnChange(double prevValue, double newValue)	Broadcasts the value change to all registered listeners, resolving the state store exactly once per event and handing it to each listener directly, so a listener body is its logic — no factory unwrapping.
protected void	notifyOnChange(@NonNull StateStore store, double prevValue, double newValue)	Broadcasts with a store the caller already resolved, so an event that had to write state itself does not resolve twice.
void	removeOnChangeListener(OnChangeRTIndicator.OnChangeListener listener)
void	setEnableEvents(boolean enableEvents)
void	setStateStoreSupplier(@NonNull Supplier<StateStore> stateStoreSupplier)	Routes this indicator's state at an externally owned store, typically the one shared by every indicator of an instrument.
protected com.google.common.base.MoreObjects.ToStringHelper	toString(com.google.common.base.MoreObjects.ToStringHelper ts)

Methods inherited from class AbstractDecorableIncrementalRTIndicator

getIndicator, reset, setClockSupplier, update

Methods inherited from class AbstractIncrementalRTIndicator

getLastUpdateValue, getPeriodCycles, getPeriods, getPrevValue, initValue, isPeriodic, isReady, prevNextValue, setPeriods, tickValue

Methods inherited from class AbstractRTIndicator

equals, getDisplayHint, getMeta, getValue, hashCode, hide, isPoison, setValue, toString, withDisplayHint, withMeta

Methods inherited from class Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface RTIndicator

getId, isHidden, ro, update, update

Constructor Details

OnChangeRTIndicator

public OnChangeRTIndicator()

OnChangeRTIndicator

public OnChangeRTIndicator(RTIndicator indicator)

Method Details

setEnableEvents

public void setEnableEvents(boolean enableEvents)

isEnableEvents

public boolean isEnableEvents()

addOnChangeListener

public void addOnChangeListener(OnChangeRTIndicator.OnChangeListener listener)

removeOnChangeListener

public void removeOnChangeListener(OnChangeRTIndicator.OnChangeListener listener)

clearOnChangeListeners

public void clearOnChangeListeners()

hasListeners

protected boolean hasListeners()

Returns:

whether any listener is registered — the gate that decides if a store is needed at all

setStateStoreSupplier

public void setStateStoreSupplier(@NonNull
 @NonNull Supplier<StateStore> stateStoreSupplier)

Routes this indicator's state at an externally owned store, typically the one shared by every indicator of an instrument. The supplier is consulted lazily, on the events that actually write , so wiring an indicator up costs nothing until it has something to persist — which matters once the store behind it is a persistent backend rather than a map.

Parameters:

stateStoreSupplier - supplies the store to use instead of this indicator's own

getStateStore

public StateStore getStateStore()

Resolves this indicator's state store: the externally supplied one if setStateStoreSupplier(Supplier) was called, otherwise a private in-memory store created on demand. Single accessor on purpose — listeners and callers must never see different stores.

Returns:

the state store this indicator writes through (never null)

nextValue

protected double nextValue(double prevValue,
 double newValue)

Fires change notifications (if events are enabled) before delegating to the parent's nextValue computation. Subclasses like WindowTimeRTIndicator override event enablement to control notification timing.

Overrides:

nextValue in class AbstractDecorableIncrementalRTIndicator

Parameters:

prevValue - the previous indicator value (or last update value, depending on override)

newValue - the new input value

Returns:

the computed indicator value

notifyOnChange

protected void notifyOnChange(double prevValue,
 double newValue)

Broadcasts the value change to all registered listeners, resolving the state store exactly once per event and handing it to each listener directly, so a listener body is its logic — no factory unwrapping. With no listeners registered nothing is resolved: the store stays uncreated .

Parameters:

prevValue - the previous indicator value

newValue - the new indicator value

notifyOnChange

protected void notifyOnChange(@NonNull
 @NonNull StateStore store,
 double prevValue,
 double newValue)

Broadcasts with a store the caller already resolved, so an event that had to write state itself does not resolve twice.

Parameters:

store - the store to hand to every listener

prevValue - the previous indicator value

newValue - the new indicator value

toString

protected com.google.common.base.MoreObjects.ToStringHelper toString(com.google.common.base.MoreObjects.ToStringHelper ts)

Overrides:

toString in class AbstractRTIndicator