From 987fd8406d65505aedecd17e51216eb0ce393fbb Mon Sep 17 00:00:00 2001
From: Adrien Hopkins <adrien.p.hopkins@gmail.com>
Date: Wed, 22 May 2019 17:32:40 -0400
Subject: Added new default methods to the Unit interface.

---
 src/org/unitConverter/unit/Unit.java | 46 ++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)

(limited to 'src/org/unitConverter/unit/Unit.java')

diff --git a/src/org/unitConverter/unit/Unit.java b/src/org/unitConverter/unit/Unit.java
index 86fc5a2..2ac107e 100755
--- a/src/org/unitConverter/unit/Unit.java
+++ b/src/org/unitConverter/unit/Unit.java
@@ -17,6 +17,7 @@
 package org.unitConverter.unit;
 
 import java.util.Objects;
+import java.util.function.DoubleUnaryOperator;
 
 import org.unitConverter.dimension.UnitDimension;
 
@@ -28,6 +29,31 @@ import org.unitConverter.dimension.UnitDimension;
  * @since v0.1.0
  */
 public interface Unit {
+	/**
+	 * Returns a unit from its base and the functions it uses to convert to and from its base.
+	 * 
+	 * <p>
+	 * For example, to get a unit representing the degree Celsius, the following code can be used:
+	 * 
+	 * {@code Unit.fromConversionFunctions(SI.KELVIN, tempK -> tempK - 273.15, tempC -> tempC + 273.15);}
+	 * </p>
+	 * 
+	 * @param base
+	 *            unit's base
+	 * @param converterFrom
+	 *            function that accepts a value expressed in the unit's base and returns that value expressed in this
+	 *            unit.
+	 * @param converterTo
+	 *            function that accepts a value expressed in the unit and returns that value expressed in the unit's
+	 *            base.
+	 * @return a unit that uses the provided functions to convert.
+	 * @since 2019-05-22
+	 */
+	public static Unit fromConversionFunctions(final BaseUnit base, final DoubleUnaryOperator converterFrom,
+			final DoubleUnaryOperator converterTo) {
+		return FunctionalUnit.valueOf(base, converterFrom, converterTo);
+	}
+
 	/**
 	 * Checks if a value expressed in this unit can be converted to a value expressed in {@code other}
 	 * 
@@ -59,6 +85,26 @@ public interface Unit {
 	 */
 	double convertFromBase(double value);
 
+	/**
+	 * Converts a value expressed in this unit to a value expressed in {@code other}.
+	 * 
+	 * @param other
+	 *            unit to convert to
+	 * @param value
+	 *            value to convert
+	 * @return converted value
+	 * @since 2019-05-22
+	 * @throws IllegalArgumentException
+	 *             if {@code other} is incompatible for conversion with this unit (as tested by
+	 *             {@link Unit#canConvertTo}).
+	 */
+	default double convertTo(final Unit other, final double value) {
+		if (this.canConvertTo(other))
+			return other.convertFromBase(this.convertToBase(value));
+		else
+			throw new IllegalArgumentException(String.format("Cannot convert from %s to %s.", this, other));
+	}
+
 	/**
 	 * Converts from a value expressed in this unit to a value expressed in this unit's base unit.
 	 * <p>
-- 
cgit v1.2.3