Made BaseUnit a subclass of LinearUnit and made an expression parser

1 files changed, 30 insertions, 121 deletions

diff --git a/src/org/unitConverter/unit/BaseUnit.java b/src/org/unitConverter/unit/BaseUnit.java
index 894d338..2def48e 100755
--- a/src/org/unitConverter/unit/BaseUnit.java
+++ b/src/org/unitConverter/unit/BaseUnit.java
@@ -28,7 +28,7 @@ import org.unitConverter.dimension.UnitDimension;
  * @since 2018-12-23
  * @since v0.1.0
  */
-public final class BaseUnit extends AbstractUnit implements OperatableUnit {
+public final class BaseUnit extends LinearUnit {
 	/**
 	 * Is this unit a full base (i.e. m, s, ... but not N, J, ...)
 	 * 
@@ -52,156 +52,65 @@ public final class BaseUnit extends AbstractUnit implements OperatableUnit {
 	 * @since v0.1.0
 	 */
 	BaseUnit(final UnitDimension dimension, final UnitSystem system) {
-		super(dimension, system);
+		super(dimension, system, 1);
 		this.isFullBase = dimension.isBase();
 	}
 
 	/**
-	 * @return this unit as a {@code LinearUnit}
-	 * @since 2019-01-25
-	 * @since v0.1.0
-	 */
-	public LinearUnit asLinearUnit() {
-		return this.times(1);
-	}
-
-	@Override
-	public double convertFromBase(final double value) {
-		return value;
-	}
-
-	@Override
-	public double convertToBase(final double value) {
-		return value;
-	}
-
-	/**
-	 * Divides this unit by another unit.
+	 * Returns the quotient of this unit and another.
+	 * <p>
+	 * Two units can be divided if they are part of the same unit system. If {@code divisor} does not meet this
+	 * condition, an {@code IllegalArgumentException} should be thrown.
+	 * </p>
 	 * 
-	 * @param other
+	 * @param divisor
 	 *            unit to divide by
 	 * @return quotient of two units
 	 * @throws IllegalArgumentException
-	 *             if this unit's system is not other's system
+	 *             if {@code divisor} is not compatible for division as described above
 	 * @throws NullPointerException
-	 *             if other is null
+	 *             if {@code divisor} is null
 	 * @since 2018-12-22
 	 * @since v0.1.0
 	 */
-	public BaseUnit dividedBy(final BaseUnit other) {
-		Objects.requireNonNull(other, "other must not be null.");
-		if (!this.getSystem().equals(other.getSystem()))
-			throw new IllegalArgumentException("Incompatible base units for division.");
-		return new BaseUnit(this.getDimension().dividedBy(other.getDimension()), this.getSystem());
-	}
+	public BaseUnit dividedBy(final BaseUnit divisor) {
+		Objects.requireNonNull(divisor, "other must not be null.");
 
-	/**
-	 * Divides this unit by a divisor
-	 * 
-	 * @param divisor
-	 *            amount to divide by
-	 * @return quotient
-	 * @since 2018-12-23
-	 * @since v0.1.0
-	 */
-	public LinearUnit dividedBy(final double divisor) {
-		return new LinearUnit(this, 1 / divisor);
-	}
-
-	@Override
-	public boolean equals(final Object obj) {
-		if (!(obj instanceof BaseUnit))
-			return false;
-		final BaseUnit other = (BaseUnit) obj;
-		return Objects.equals(this.getSystem(), other.getSystem())
-				&& Objects.equals(this.getDimension(), other.getDimension());
-	}
-
-	@Override
-	public int hashCode() {
-		final int prime = 31;
-		int result = 1;
-		result = result * prime + this.getSystem().hashCode();
-		result = result * prime + this.getDimension().hashCode();
-		return result;
-	}
-
-	@Override
-	public LinearUnit negated() {
-		return this.times(-1);
-	}
-
-	@Override
-	public OperatableUnit plus(final OperatableUnit addend) {
-		Objects.requireNonNull(addend, "addend must not be null.");
-
-		// reject addends that cannot be added to this unit
-		if (!this.getSystem().equals(addend.getSystem()))
-			throw new IllegalArgumentException(
-					String.format("Incompatible units for addition or subtraction \"%s\" and \"%s\".", this, addend));
-		if (!this.getDimension().equals(addend.getDimension()))
+		// check that these units can be multiplied
+		if (!this.getSystem().equals(divisor.getSystem()))
 			throw new IllegalArgumentException(
-					String.format("Incompatible units for addition or subtraction \"%s\" and \"%s\".", this, addend));
-
-		// add them together
-		if (addend instanceof BaseUnit)
-			return this.times(2);
-		else
-			return addend.plus(this);
-	}
+					String.format("Incompatible units for division \"%s\" and \"%s\".", this, divisor));
 
-	@Override
-	public BaseUnit reciprocal() {
-		return this.toExponent(-1);
+		return new BaseUnit(this.getDimension().dividedBy(divisor.getDimension()), this.getSystem());
 	}
 
 	/**
-	 * Multiplies this unit by another unit.
+	 * Returns the product of this unit and another.
+	 * <p>
+	 * Two units can be multiplied if they are part of the same unit system. If {@code multiplier} does not meet this
+	 * condition, an {@code IllegalArgumentException} should be thrown.
+	 * </p>
 	 * 
-	 * @param other
+	 * @param multiplier
 	 *            unit to multiply by
 	 * @return product of two units
 	 * @throws IllegalArgumentException
-	 *             if this unit's system is not other's system
+	 *             if {@code multiplier} is not compatible for multiplication as described above
 	 * @throws NullPointerException
-	 *             if other is null
+	 *             if {@code multiplier} is null
 	 * @since 2018-12-22
 	 * @since v0.1.0
 	 */
-	public BaseUnit times(final BaseUnit other) {
-		Objects.requireNonNull(other, "other must not be null.");
-		if (!this.getSystem().equals(other.getSystem()))
-			throw new IllegalArgumentException("Incompatible base units for multiplication.");
-		return new BaseUnit(this.getDimension().times(other.getDimension()), this.getSystem());
-	}
-
-	/**
-	 * Multiplies this unit by a multiplier.
-	 * 
-	 * @param multiplier
-	 *            amount to multiply by
-	 * @return product
-	 * @since 2018-12-23
-	 * @since v0.1.0
-	 */
-	public LinearUnit times(final double multiplier) {
-		return new LinearUnit(this, multiplier);
-	}
+	public BaseUnit times(final BaseUnit multiplier) {
+		Objects.requireNonNull(multiplier, "other must not be null");
 
-	@Override
-	public OperatableUnit times(final OperatableUnit multiplier) {
-		Objects.requireNonNull(multiplier, "multiplier must not be null.");
-
-		// reject multipliers that cannot be muliplied by this unit
+		// check that these units can be multiplied
 		if (!this.getSystem().equals(multiplier.getSystem()))
-			throw new IllegalArgumentException(String
-					.format("Incompatible units for multiplication or division \"%s\" and \"%s\".", this, multiplier));
+			throw new IllegalArgumentException(
+					String.format("Incompatible units for multiplication \"%s\" and \"%s\".", this, multiplier));
 
 		// multiply the units
-		if (multiplier instanceof BaseUnit)
-			return new BaseUnit(this.getDimension().times(multiplier.getDimension()), this.getSystem());
-		else
-			return multiplier.times(this);
+		return new BaseUnit(this.getDimension().times(multiplier.getDimension()), this.getSystem());
 	}
 
 	/**