First typed time series: electricity

src/main/kotlin/DateTimeUtil.kt

@@ -0,0 +1,12 @@
+package com.zenmo.timeseries
+
+import java.time.Duration
+import java.time.temporal.TemporalAmount
+
+private const val SECONDS_IN_HOUR = 3600.0
+
+internal fun TemporalAmount.hours(): Double = Duration.from(this).toSeconds() / SECONDS_IN_HOUR
+
+internal fun TemporalAmount.multiplicateInverseHours(): Double {
+    return 1 / (this.hours())
+}

src/main/kotlin/TimeSeriesBuilder.kt

@@ -1,5 +1,7 @@
 package com.zenmo.timeseries
 
+import com.zenmo.timeseries.typed.ElectricityKwhTimeSeries
+import com.zenmo.timeseries.typed.ElectricityTimeSeries
 import com.zenmo.timeseries.untyped.ArrayTimeSeries
 import com.zenmo.timeseries.untyped.TimeSeries
 import com.zenmo.timeseries.untyped.TimeSeriesAccessor
@@ -34,6 +36,8 @@ class TimeSeriesBuilder {
         }
     }
 
+    fun buildElectricityKwhTimeSeries(): ElectricityTimeSeries = ElectricityKwhTimeSeries(build())
+
     /**
      * Start of the first interval of the [values].
      * Must support arithmetic using the [step].

src/main/kotlin/typed/ElectricityKwhTimeSeries.kt

@@ -0,0 +1,20 @@
+package com.zenmo.timeseries.typed
+
+import com.zenmo.timeseries.multiplicateInverseHours
+import com.zenmo.timeseries.untyped.TimeSeries
+import java.time.temporal.Temporal
+
+/**
+ * A time series of electric energy backed by a raw time series of kWh.
+ * Can directly take the quarter-hourly values given by an electricity supplier.
+ */
+internal class ElectricityKwhTimeSeries(
+    internal val kwhTimeSeries: TimeSeries,
+) : ElectricityTimeSeries {
+    override fun getKwh(intervalStart: Temporal): Double = kwhTimeSeries[intervalStart]
+
+    private val multiplicateInverseHours: Double = kwhTimeSeries.step.multiplicateInverseHours()
+
+    override fun getKw(intervalStart: Temporal): Double =
+        getKwh(intervalStart) * multiplicateInverseHours
+}

src/main/kotlin/typed/ElectricityTimeSeries.kt

@@ -0,0 +1,3 @@
+package com.zenmo.timeseries.typed
+
+interface ElectricityTimeSeries: EnergyTimeSeries, PowerTimeSeries

src/main/kotlin/typed/EnergyTimeSeries.kt

@@ -0,0 +1,7 @@
+package com.zenmo.timeseries.typed
+
+import java.time.temporal.Temporal
+
+interface EnergyTimeSeries {
+    fun getKwh(intervalStart: Temporal): Double
+}

src/main/kotlin/typed/PowerTimeSeries.kt

@@ -0,0 +1,7 @@
+package com.zenmo.timeseries.typed
+
+import java.time.temporal.Temporal
+
+interface PowerTimeSeries {
+    fun getKw(intervalStart: Temporal): Double
+}

src/main/kotlin/untyped/ArrayTimeSeries.kt

@@ -104,7 +104,7 @@ internal open class ArrayTimeSeries(
         return result
     }
 
-    fun size() = values.size
+    internal fun size() = values.size
 
     fun toBuilder() = TimeSeriesBuilder().start(start).step(step).values(values)
 }

src/test/java/com/zenmo/timeseries/typed/ElectricityTimeSeriesTest.java

@@ -0,0 +1,31 @@
+package com.zenmo.timeseries.typed;
+
+import com.zenmo.timeseries.untyped.TimeSeries;
+import org.junit.jupiter.api.Test;
+
+import java.time.Duration;
+import java.time.Instant;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+class ElectricityTimeSeriesTest {
+    @Test
+    void test() {
+        var start = Instant.parse("2025-01-01T00:00:00Z");
+        var electricityTimeSeries = TimeSeries.builder()
+                .values(new double[]{2.0, 3.0, 4.0})
+                .start(start)
+                .step(Duration.ofMinutes(15))
+                .buildElectricityKwhTimeSeries();
+
+        assertEquals(2.0, electricityTimeSeries.getKwh(start));
+        assertEquals(8.0, electricityTimeSeries.getKw(start));
+        assertEquals(3.0, electricityTimeSeries.getKwh(start.plus(Duration.ofMinutes(15))));
+        assertEquals(12.0, electricityTimeSeries.getKw(start.plus(Duration.ofMinutes(15))));
+        assertEquals(4.0, electricityTimeSeries.getKwh(start.plus(Duration.ofMinutes(30))));
+        assertEquals(16.0, electricityTimeSeries.getKw(start.plus(Duration.ofMinutes(30))));
+        assertThrows(IndexOutOfBoundsException.class, () -> electricityTimeSeries.getKwh(start.plus(Duration.ofMinutes(45))));
+        assertThrows(IndexOutOfBoundsException.class, () -> electricityTimeSeries.getKw(start.plus(Duration.ofMinutes(45))));
+    }
+}

src/test/java/com/zenmo/timeseries/untyped/WraparoundTest.java

@@ -7,7 +7,6 @@
 import java.time.Instant;
 import java.time.Period;
 import java.time.ZonedDateTime;
-import java.time.temporal.ChronoField;
 import java.time.temporal.Temporal;
 import java.util.stream.DoubleStream;