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-rw-r--r--src/org/unitConverter/math/DecimalComparison.java67
-rw-r--r--src/org/unitConverter/newUnits/LinearUnit.java29
-rw-r--r--src/org/unitConverter/newUnits/UnitPrefix.java134
3 files changed, 229 insertions, 1 deletions
diff --git a/src/org/unitConverter/math/DecimalComparison.java b/src/org/unitConverter/math/DecimalComparison.java
index 7cdbe5b..859e8da 100644
--- a/src/org/unitConverter/math/DecimalComparison.java
+++ b/src/org/unitConverter/math/DecimalComparison.java
@@ -16,6 +16,8 @@
*/
package org.unitConverter.math;
+import java.math.BigDecimal;
+
/**
* A class that contains methods to compare float and double values.
*
@@ -44,6 +46,18 @@ public final class DecimalComparison {
/**
* Tests for equality of double values using {@link #DOUBLE_EPSILON}.
+ * <p>
+ * <strong>WARNING: </strong>this method is not technically transitive. If a and b are off by slightly less than
+ * {@code epsilon * max(abs(a), abs(b))}, and b and c are off by slightly less than
+ * {@code epsilon * max(abs(b), abs(c))}, then equals(a, b) and equals(b, c) will both return true, but equals(a, c)
+ * will return false. However, this situation is very unlikely to ever happen in a real programming situation.
+ * <p>
+ * If this does become a concern, some ways to solve this problem:
+ * <ol>
+ * <li>Raise the value of epsilon using {@link #equals(double, double, double)} (this does not make a violation of
+ * transitivity impossible, it just significantly reduces the chances of it happening)
+ * <li>Use {@link BigDecimal} instead of {@code double} (this will make a violation of transitivity 100% impossible)
+ * </ol>
*
* @param a
* first value to test
@@ -52,6 +66,7 @@ public final class DecimalComparison {
* @return whether they are equal
* @since 2019-03-18
* @since v0.2.0
+ * @see #hashCode(double)
*/
public static final boolean equals(final double a, final double b) {
return DecimalComparison.equals(a, b, DOUBLE_EPSILON);
@@ -60,6 +75,19 @@ public final class DecimalComparison {
/**
* Tests for double equality using a custom epsilon value.
*
+ * <p>
+ * <strong>WARNING: </strong>this method is not technically transitive. If a and b are off by slightly less than
+ * {@code epsilon * max(abs(a), abs(b))}, and b and c are off by slightly less than
+ * {@code epsilon * max(abs(b), abs(c))}, then equals(a, b) and equals(b, c) will both return true, but equals(a, c)
+ * will return false. However, this situation is very unlikely to ever happen in a real programming situation.
+ * <p>
+ * If this does become a concern, some ways to solve this problem:
+ * <ol>
+ * <li>Raise the value of epsilon (this does not make a violation of transitivity impossible, it just significantly
+ * reduces the chances of it happening)
+ * <li>Use {@link BigDecimal} instead of {@code double} (this will make a violation of transitivity 100% impossible)
+ * </ol>
+ *
* @param a
* first value to test
* @param b
@@ -77,6 +105,19 @@ public final class DecimalComparison {
/**
* Tests for equality of float values using {@link #FLOAT_EPSILON}.
*
+ * <p>
+ * <strong>WARNING: </strong>this method is not technically transitive. If a and b are off by slightly less than
+ * {@code epsilon * max(abs(a), abs(b))}, and b and c are off by slightly less than
+ * {@code epsilon * max(abs(b), abs(c))}, then equals(a, b) and equals(b, c) will both return true, but equals(a, c)
+ * will return false. However, this situation is very unlikely to ever happen in a real programming situation.
+ * <p>
+ * If this does become a concern, some ways to solve this problem:
+ * <ol>
+ * <li>Raise the value of epsilon using {@link #equals(float, float, float)} (this does not make a violation of
+ * transitivity impossible, it just significantly reduces the chances of it happening)
+ * <li>Use {@link BigDecimal} instead of {@code float} (this will make a violation of transitivity 100% impossible)
+ * </ol>
+ *
* @param a
* first value to test
* @param b
@@ -92,6 +133,19 @@ public final class DecimalComparison {
/**
* Tests for float equality using a custom epsilon value.
*
+ * <p>
+ * <strong>WARNING: </strong>this method is not technically transitive. If a and b are off by slightly less than
+ * {@code epsilon * max(abs(a), abs(b))}, and b and c are off by slightly less than
+ * {@code epsilon * max(abs(b), abs(c))}, then equals(a, b) and equals(b, c) will both return true, but equals(a, c)
+ * will return false. However, this situation is very unlikely to ever happen in a real programming situation.
+ * <p>
+ * If this does become a concern, some ways to solve this problem:
+ * <ol>
+ * <li>Raise the value of epsilon (this does not make a violation of transitivity impossible, it just significantly
+ * reduces the chances of it happening)
+ * <li>Use {@link BigDecimal} instead of {@code float} (this will make a violation of transitivity 100% impossible)
+ * </ol>
+ *
* @param a
* first value to test
* @param b
@@ -106,6 +160,19 @@ public final class DecimalComparison {
return Math.abs(a - b) <= epsilon * Math.max(Math.abs(a), Math.abs(b));
}
+ /**
+ * Takes the hash code of doubles. Values that are equal according to {@link #equals(double, double)} will have the
+ * same hash code.
+ *
+ * @param d
+ * double to hash
+ * @return hash code of double
+ * @since 2019-10-16
+ */
+ public static final int hash(final double d) {
+ return Float.hashCode((float) d);
+ }
+
// You may NOT get any DecimalComparison instances
private DecimalComparison() {
throw new AssertionError();
diff --git a/src/org/unitConverter/newUnits/LinearUnit.java b/src/org/unitConverter/newUnits/LinearUnit.java
index 5a589b7..7600dad 100644
--- a/src/org/unitConverter/newUnits/LinearUnit.java
+++ b/src/org/unitConverter/newUnits/LinearUnit.java
@@ -29,6 +29,21 @@ import org.unitConverter.math.ObjectProduct;
*/
public final class LinearUnit extends AbstractUnit {
/**
+ * Gets a {@code LinearUnit} from a unit and a value. For example, converts '59 °F' to a linear unit with the value
+ * of '288.15 K'
+ *
+ * @param unit
+ * unit to convert
+ * @param value
+ * value to convert
+ * @return value expressed as a {@code LinearUnit}
+ * @since 2019-10-16
+ */
+ public static LinearUnit fromValue(final Unit unit, final double value) {
+ return new LinearUnit(unit.getBase(), unit.convertToBase(value));
+ }
+
+ /**
* Gets a {@code LinearUnit} from a unit base and a conversion factor. In other words, gets the product of
* {@code unitBase} and {@code conversionFactor}, expressed as a {@code LinearUnit}.
*
@@ -129,7 +144,7 @@ public final class LinearUnit extends AbstractUnit {
@Override
public int hashCode() {
- return Objects.hash(this.getBase(), this.getConversionFactor());
+ return 31 * this.getBase().hashCode() + DecimalComparison.hash(this.getConversionFactor());
}
/**
@@ -258,4 +273,16 @@ public final class LinearUnit extends AbstractUnit {
return Double.toString(this.conversionFactor) + " * " + this.getBase().toString(BaseUnit::getSymbol);
}
+ /**
+ * Returns the result of applying {@code prefix} to this unit.
+ *
+ * @param prefix
+ * prefix to apply
+ * @return unit with prefix
+ * @since 2019-03-18
+ * @since v0.2.0
+ */
+ public LinearUnit withPrefix(final UnitPrefix prefix) {
+ return this.times(prefix.getMultiplier());
+ }
}
diff --git a/src/org/unitConverter/newUnits/UnitPrefix.java b/src/org/unitConverter/newUnits/UnitPrefix.java
new file mode 100644
index 0000000..905ca19
--- /dev/null
+++ b/src/org/unitConverter/newUnits/UnitPrefix.java
@@ -0,0 +1,134 @@
+/**
+ * Copyright (C) 2019 Adrien Hopkins
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <https://www.gnu.org/licenses/>.
+ */
+package org.unitConverter.newUnits;
+
+import org.unitConverter.math.DecimalComparison;
+
+/**
+ * A prefix that can be applied to a {@code LinearUnit} to multiply it by some value
+ *
+ * @author Adrien Hopkins
+ * @since 2019-10-16
+ */
+public final class UnitPrefix {
+ /**
+ * The number that this prefix multiplies units by
+ *
+ * @since 2019-10-16
+ */
+ private final double multiplier;
+
+ /**
+ * Creates the {@code DefaultUnitPrefix}.
+ *
+ * @param multiplier
+ * @since 2019-01-14
+ * @since v0.2.0
+ */
+ private UnitPrefix(final double multiplier) {
+ this.multiplier = multiplier;
+ }
+
+ /**
+ * Divides this prefix by a scalar
+ *
+ * @param divisor
+ * number to divide by
+ * @return quotient of prefix and scalar
+ * @since 2019-10-16
+ */
+ public UnitPrefix dividedBy(final double divisor) {
+ return new UnitPrefix(this.getMultiplier() / divisor);
+ }
+
+ /**
+ * Divides this prefix by {@code other}.
+ *
+ * @param other
+ * prefix to divide by
+ * @return quotient of prefixes
+ * @since 2019-04-13
+ * @since v0.2.0
+ */
+ public UnitPrefix dividedBy(final UnitPrefix other) {
+ return new UnitPrefix(this.getMultiplier() / other.getMultiplier());
+ }
+
+ @Override
+ public boolean equals(final Object obj) {
+ if (this == obj)
+ return true;
+ if (obj == null)
+ return false;
+ if (!(obj instanceof UnitPrefix))
+ return false;
+ final UnitPrefix other = (UnitPrefix) obj;
+ return DecimalComparison.equals(this.getMultiplier(), other.getMultiplier());
+ }
+
+ public double getMultiplier() {
+ return this.multiplier;
+ }
+
+ @Override
+ public int hashCode() {
+ return DecimalComparison.hash(this.getMultiplier());
+ }
+
+ /**
+ * Multiplies this prefix by a scalar
+ *
+ * @param multiplicand
+ * number to multiply by
+ * @return product of prefix and scalar
+ * @since 2019-10-16
+ */
+ public UnitPrefix times(final double multiplicand) {
+ return new UnitPrefix(this.getMultiplier() * multiplicand);
+ }
+
+ /**
+ * Multiplies this prefix by {@code other}.
+ *
+ * @param other
+ * prefix to multiply by
+ * @return product of prefixes
+ * @since 2019-04-13
+ * @since v0.2.0
+ */
+ public UnitPrefix times(final UnitPrefix other) {
+ return new UnitPrefix(this.getMultiplier() * other.getMultiplier());
+ }
+
+ /**
+ * Raises this prefix to an exponent.
+ *
+ * @param exponent
+ * exponent to raise to
+ * @return result of exponentiation.
+ * @since 2019-04-13
+ * @since v0.2.0
+ */
+ public UnitPrefix toExponent(final double exponent) {
+ return new UnitPrefix(Math.pow(this.getMultiplier(), exponent));
+ }
+
+ @Override
+ public String toString() {
+ return String.format("Unit prefix equal to %s", this.multiplier);
+ }
+}
generated by cgit v1.2.3 (git 2.46.0) at 2025-10-03 22:15:25 +0000