Errors and validation

rbed reports a mistake as early as it can, most of them when the Detector is built, and always with an exception whose message names what is wrong.

A warm room

A room's temperature is reported once a second; it is 28 °C from 10 to 29 s and 22 °C otherwise. Warm holds while the average of the last few Samples is above 25 °C, for a duration; Hot holds while a Warm Event runs and the temperature itself is above 27 °C.

The live chart and its controls need JavaScript. The tables show the Events at the default parameters.

The site cannot run the default parameters: (JavaScript) TypeError: Cannot read properties of undefined (reading 'length')

import static io.github.romanhaendler.rbed.Conditions.*;

import io.github.romanhaendler.rbed.*;
import java.time.Duration;
import java.util.Map;

Channel temp = Channel.named("temp");

Rule warm = Rule.named("Warm")
    .when(temp.averageOverSamples(5).above(25))
    .forDuration(Duration.ofSeconds(2));
Rule hot = Rule.named("Hot").when(during(warm).and(temp.above(27)));
Detector detector = Detector.builder()
    .retentionLimit(10)
    .rules(warm, hot)
    .build();

for (int s = 0; s <= 40; s++) {   // one Sample a second
  detector.push(s * 1_000L, Map.of(temp, s >= 10 && s < 30 ? 28.0 : 22.0));
}
detector.close();

At the defaults, the average over 5 Samples rises above 25 °C at 12 s, the third warm Sample, and Warm is Confirmed two seconds later; Hot starts with that confirmation and Ends at 30 s, the first cool Sample.

Things to try

• Raise Average over above the Retention Limit, the most entries one window may keep (1,000,000 by default, 10 here). An average over n Samples must keep n values, so build() rejects an n above the Retention Limit and says how to fix it: raise the limit with Detector.builder().retentionLimit(...).
• Set the Retention Limit to 0: retentionLimit itself rejects a limit below one.
• Set Warm for to −1 s: forDuration rejects a negative duration as soon as the Rule is written, before any Detector exists.
• Add Hot before Warm. A Rule may only refer to Rules added before it, since Rules are evaluated in the order they are added, so build() rejects Hot.

What else is rejected

• An empty Rule or Channel name, a Rule without when, two Rules with the same name.
• forDuration or forSamples before any when or endWhen; negative durations, forSamples(0), between with its low above its high.
• A sampling rate outside (0, 1000] Hz; a History Event that has not Ended, or whose name matches no Rule; one Channel name used both as a Pulse Channel and as an ordinary one.
• While running: a timestamp not after the previous Sample or advance (or, with History, not after its latest end); a NaN, infinite or null value (the Sample is then ignored); pushing after close(); the wrong push for the sampling mode.
• A Rule referring to itself, to a Rule added after it, or to one not added at all (build()).
• Reading the Aggregates of a Channel the Rule does not aggregate.

The Restarts: History and Silent sensors pages show restarts and time advances that stay within these rules. What the Retention Limit is, and what happens when a window reaches it, is on Memory and the Retention Limit.

Reference

• Errors and validation in the README, the canonical text, with the method that reports each mistake

Methods used: Channel.named, Rule.named, Rule.when, ChannelExpression.averageOverSamples, Expression.above, Rule.forDuration, Conditions.during, Condition.and, Detector.builder, Detector.Builder.retentionLimit, Detector.Builder.rules, Detector.Builder.build, Detector.push, Detector.close.