velox.api.layer1.layers.strategies.interfaces

Interface OnlineCalculatable

public interface OnlineCalculatable

Strategy implementing this interfaces should support 2 types of requests. 1. Calculate value for given time points 2. Calculate value on fly when receiving new updates Calculated value can be any object Bottom panel will currently work with Double objects representing current value

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	OnlineCalculatable.Marker If passed as value it will cause marker to be drawn at that place (currently works only for Layer1ApiUserMessageModifyIndicator.GraphType.PRIMARY).
static class	OnlineCalculatable.ValueBundle

Method Summary

Modifier and Type	Method and Description
default boolean	allowPartialUpdates(java.lang.String indicatorName, java.lang.String alias)
void	calculateValuesInRange(java.lang.String indicatorName, java.lang.String indicatorAlias, long t0, long intervalWidth, int intervalsNumber, CalculatedResultListener listener) 1st request type: Should calculate left to right values in given time points t0; t0 + intervalWidth; t0 + 2 * intervalWidth ...
OnlineValueCalculatorAdapter	createOnlineValueCalculator(java.lang.String indicatorName, java.lang.String indicatorAlias, long time, java.util.function.Consumer<java.lang.Object> listener, InvalidateInterface invalidateInterface) 2nd request type:
default boolean	shouldRepeatCalculateValuesInRange(java.lang.String indicatorName, java.lang.String indicatorAlias, long intervalWidth, long timePassed) Experimental!

Method Detail

calculateValuesInRange

void calculateValuesInRange(java.lang.String indicatorName,
                            java.lang.String indicatorAlias,
                            long t0,
                            long intervalWidth,
                            int intervalsNumber,
                            CalculatedResultListener listener)

1st request type: Should calculate left to right values in given time points t0; t0 + intervalWidth; t0 + 2 * intervalWidth ... t0 + (intervalsNumber - 1) * intervalWidh)

Parameters:

indicatorName - name of indicator

indicatorAlias - alias of this indicator

t0 - time of 1st value (in ns)

intervalWidth - width of one calculated interval (in ns)

intervalsNumber - number of values to calculate, >= 0

listener -

createOnlineValueCalculator

OnlineValueCalculatorAdapter createOnlineValueCalculator(java.lang.String indicatorName,
                                                         java.lang.String indicatorAlias,
                                                         long time,
                                                         java.util.function.Consumer<java.lang.Object> listener,
                                                         InvalidateInterface invalidateInterface)

2nd request type:

Parameters:

indicatorName - name of indicator

indicatorAlias - alias of this indicator

time - starting with this time values are computed online

listener - can be used in following ways:
a) you can return generated events via listener (see CalculatedResultListener.provideResponse(Object) for supported object types
b) you can use IndicatorFullValues to fully update historical values of your indicator

invalidateInterface - can be used to invalidate indicator

Returns:

value calculator for this strategy

shouldRepeatCalculateValuesInRange

default boolean shouldRepeatCalculateValuesInRange(java.lang.String indicatorName,
                                                   java.lang.String indicatorAlias,
                                                   long intervalWidth,
                                                   long timePassed)

Experimental!

By default Bookmap will repeat calculateValuesInRange(String, String, long, long, int, CalculatedResultListener) request if by the time response is handled more than one intervalWidth passed. However sometimes (if calculateValuesInRange is relatively slow and/or user is zoomed in closely, so chart moves fast) it can be repeated too many times (or even continiously, as long as chart moves). While it can be acceptable in some cases, you can improve the performance by telling bookmap to switch to OnlineValueCalculatorAdapter earlier.

You should always return false when default implementation does that. However you can also return false when you believe there are not too many intervals and not too much time passed. It's strongly recommended to always return true if both more than 5 seconds and more than 3 intervals passed, since Bookmap will drop data from relevant caches when both conditions are no longer true. Ignoring that will result in not getting some of the updates in online calculator (which might be acceptable for some indicators, in which case it's ok). It's also important that this method doesn't block for too long.

Parameters:

indicatorName - name of indicator

indicatorAlias - alias of this indicator

intervalWidth - width of one calculated interval (in ns).

timePassed - time passed since the end of calculateValuesInRange(String, String, long, long, int, CalculatedResultListener) range

Returns:

false to switch to OnlineValueCalculatorAdapter, true to use calculateValuesInRange(String, String, long, long, int, CalculatedResultListener) again.

allowPartialUpdates

default boolean allowPartialUpdates(java.lang.String indicatorName,
                                    java.lang.String alias)

Parameters:

indicatorName - name of indicator

alias - alias of this indicator Override you want your indicator to receive only full chart range requests (i.e. you don't want to receive 0-1000 pixels request, and then 1000-1020 request to catch up with chart)

Returns:

true if you allow partial requests (default implementation), false otherwise