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Merged
fkleedorfer merged 2 commits into from
Jul 25, 2025
Merged

Strip trailing zeros resulting from unit conversion #116

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a7a13ab
Strip trailing zeros resulting from unit conversion
fkleedorfer Jul 25, 2025
6970666
Ensure scale >= 0 in conversion results
fkleedorfer Jul 25, 2025
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5 changes: 5 additions & 0 deletions CHANGELOG.md
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Original file line number Diff line number Diff line change
Expand Up @@ -7,6 +7,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0

## [Unreleased]

### Fixed

- `Unit.convert()` and `Unit.getConversionMultiplier(Unit)` now strip any trailing fractional zeros and the
scale of the result is >= 0.

## [7.0.0] - 2025-07-22

### Added
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58 changes: 35 additions & 23 deletions qudtlib-model/src/main/java/io/github/qudtlib/model/Unit.java
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Expand Up @@ -401,10 +401,16 @@ public BigDecimal convert(BigDecimal value, Unit toUnit, QuantityKind quantityKi
? BigDecimal.ZERO
: toUnit.getConversionOffset().orElse(BigDecimal.ZERO);
BigDecimal toMultiplier = toUnit.getConversionMultiplier().orElse(BigDecimal.ONE);
return value.add(fromOffset)
.multiply(fromMultiplier, MathContext.DECIMAL128)
.divide(toMultiplier, MathContext.DECIMAL128)
.subtract(toOffset);
BigDecimal result =
value.add(fromOffset)
.multiply(fromMultiplier, MathContext.DECIMAL128)
.divide(toMultiplier, MathContext.DECIMAL128)
.subtract(toOffset)
.stripTrailingZeros();
if (result.scale() < 0) {
result = result.setScale(0);
}
return result;
}

/**
Expand All @@ -427,25 +433,31 @@ public BigDecimal getConversionMultiplier(Unit toUnit) {
}
Optional<BigDecimal> fromMultiplier = this.getConversionMultiplier();
Optional<BigDecimal> toMultiplier = toUnit.getConversionMultiplier();
return fromMultiplier
.map(
from ->
toMultiplier
.map(to -> from.divide(to, MathContext.DECIMAL128))
.orElse(null))
.orElseThrow(
() ->
new InconvertibleQuantitiesException(
String.format(
"Cannot convert %s(%s) to %s(%s)",
this.getIriAbbreviated(),
this.getConversionMultiplier().isEmpty()
? "no multiplier"
: "has multiplier",
toUnit.getIriAbbreviated(),
toUnit.getConversionMultiplier().isEmpty()
? "no multiplier"
: "has multiplier")));
BigDecimal result =
fromMultiplier
.map(
from ->
toMultiplier
.map(to -> from.divide(to, MathContext.DECIMAL128))
.orElse(null))
.orElseThrow(
() ->
new InconvertibleQuantitiesException(
String.format(
"Cannot convert %s(%s) to %s(%s)",
this.getIriAbbreviated(),
this.getConversionMultiplier().isEmpty()
? "no multiplier"
: "has multiplier",
toUnit.getIriAbbreviated(),
toUnit.getConversionMultiplier().isEmpty()
? "no multiplier"
: "has multiplier")));
result = result.stripTrailingZeros();
if (result.scale() < 0) {
result = result.setScale(0);
}
return result;
}

public boolean conversionOffsetDiffers(Unit other) {
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8 changes: 5 additions & 3 deletions qudtlib-test/src/test/java/io/github/qudtlib/QudtTests.java
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Expand Up @@ -569,10 +569,12 @@ public void testMilliSV__PER__HR_to_MicroSV__PER__HR() {
u.getIriLocalname(),
u.getConversionMultiplier().get().toString())));
*/
MatcherAssert.assertThat(
BigDecimal converted =
Qudt.convert(
new BigDecimal("15.12"), Units.MilliSV__PER__HR, Units.MicroSV__PER__HR),
Matchers.comparesEqualTo(new BigDecimal(15120)));
new BigDecimal("15.12"), Units.MilliSV__PER__HR, Units.MicroSV__PER__HR);
MatcherAssert.assertThat(converted, Matchers.comparesEqualTo(new BigDecimal(15120)));
BigDecimal expected = new BigDecimal(15120);
assertEquals(expected, converted);
}

@Test
Expand Down