Measures

src/main/java/gov/hhs/aspr/ms/util/measures/BaseUnit.java

@@ -0,0 +1,232 @@
+package gov.hhs.aspr.ms.util.measures;
+
+import gov.hhs.aspr.ms.util.errors.ContractException;
+
+/**
+ * A BaseUnit represents a unit of measure for some particular measure. For
+ * example, meter, foot, mile all measure length and second, minute and hour all
+ * measure time.
+ */
+public final class BaseUnit {
+	private final String name;
+	private final double value;
+	private final String shortName;
+	private final Measure measure;
+
+	/**
+	 * Creates a unit from another unit and applies a scalar to that unit. The name
+	 * and short name are used in labeling.
+	 * 
+	 * @throws ContractException
+	 *                           <ul>
+	 *                           <li>{@linkplain MeasuresError#NULL_UNIT_NAME} if
+	 *                           the name is null</li>
+	 *                           <li>{@linkplain MeasuresError#BLANK_UNIT_NAME} if
+	 *                           the name is empty or contains only white space
+	 *                           characters</li>
+	 *                           <li>{@linkplain MeasuresError#NULL_UNIT_NAME} if
+	 *                           the short name is null</li>
+	 *                           <li>{@linkplain MeasuresError#BLANK_UNIT_NAME} if
+	 *                           the short name is empty or contains only white
+	 *                           space characters</li>
+	 *                           <li>{@linkplain MeasuresError#NULL_UNIT} if the
+	 *                           unit is null</li>
+	 *                           <li>{@linkplain MeasuresError#NON_POSITIVE_SCALAR_VALUE}
+	 *                           if the scalar is not positive</li>
+	 *                           </ul>
+	 */
+	public BaseUnit(BaseUnit baseUnit, double scalar, String name, String shortName) {
+		if (name == null) {
+			throw new ContractException(MeasuresError.NULL_UNIT_NAME);
+		}
+
+		if (name.isBlank()) {
+			throw new ContractException(MeasuresError.BLANK_UNIT_NAME);
+		}
+
+		if (shortName == null) {
+			throw new ContractException(MeasuresError.NULL_UNIT_NAME);
+		}
+
+		if (shortName.isBlank()) {
+			throw new ContractException(MeasuresError.BLANK_UNIT_NAME);
+		}
+
+		if (baseUnit == null) {
+			throw new ContractException(MeasuresError.NULL_UNIT);
+		}
+
+		if (scalar <= 0) {
+			throw new ContractException(MeasuresError.NON_POSITIVE_SCALAR_VALUE);
+		}
+
+		this.measure = baseUnit.getMeasure();
+		this.name = name;
+		this.shortName = shortName;
+		this.value = baseUnit.getValue() * scalar;
+	}
+
+	/**
+	 * Creates a unit based on the give measure to that unit. The name and short
+	 * name are used in labeling. The unit's value will be 1.
+	 * 
+	 * @throws ContractException
+	 *                           <ul>
+	 *                           <li>{@linkplain MeasuresError#NULL_UNIT_NAME} if
+	 *                           the name is null</li>
+	 *                           <li>{@linkplain MeasuresError#BLANK_UNIT_NAME} if
+	 *                           the name is empty or contains only white space
+	 *                           characters</li>
+	 *                           <li>{@linkplain MeasuresError#NULL_UNIT_NAME} if
+	 *                           the short name is null</li>
+	 *                           <li>{@linkplain MeasuresError#BLANK_UNIT_NAME} if
+	 *                           the short name is empty or contains only white
+	 *                           space characters</li>
+	 *                           <li>{@linkplain MeasuresError#NULL_MEASURE} if the
+	 *                           measure is null</li>
+	 *                           </ul>
+	 */
+	public BaseUnit(Measure measure, String name, String shortName) {
+		if (name == null) {
+			throw new ContractException(MeasuresError.NULL_UNIT_NAME);
+		}
+
+		if (name.isBlank()) {
+			throw new ContractException(MeasuresError.BLANK_UNIT_NAME);
+		}
+
+		if (shortName == null) {
+			throw new ContractException(MeasuresError.NULL_UNIT_NAME);
+		}
+
+		if (shortName.isBlank()) {
+			throw new ContractException(MeasuresError.BLANK_UNIT_NAME);
+		}
+
+		if (measure == null) {
+			throw new ContractException(MeasuresError.NULL_MEASURE);
+		}
+
+		this.measure = measure;
+		this.name = name;
+		this.shortName = shortName;
+		this.value = 1;
+	}
+
+	/**
+	 * Returns the name of this unit
+	 */
+	public String getLongName() {
+		return name;
+	}
+
+	/**
+	 * Returns the short name of this unit
+	 */
+	public String getShortName() {
+		return shortName;
+	}
+
+	/**
+	 * Returns the measure of this unit
+	 */
+	public Measure getMeasure() {
+		return measure;
+	}
+
+	/**
+	 * Returns the value of this unit. Typically, one unit for each measure has a
+	 * value of 1 and is the basis for all other units sharing that measure.
+	 */
+	public double getValue() {
+		return value;
+	}
+
+	/**
+	 * Boilerplate implementation consistent with equals()
+	 */
+	@Override
+	public int hashCode() {
+		final int prime = 31;
+		int result = 1;
+		result = prime * result + ((measure == null) ? 0 : measure.hashCode());
+		result = prime * result + ((name == null) ? 0 : name.hashCode());
+		result = prime * result + ((shortName == null) ? 0 : shortName.hashCode());
+		long temp;
+		temp = Double.doubleToLongBits(value);
+		result = prime * result + (int) (temp ^ (temp >>> 32));
+		return result;
+	}
+
+	/**
+	 * Two units are equal if and only if the have equal measures, equal names,
+	 * equal short names and equal values.
+	 */
+	@Override
+	public boolean equals(Object obj) {
+		if (this == obj) {
+			return true;
+		}
+		if (!(obj instanceof BaseUnit)) {
+			return false;
+		}
+		BaseUnit other = (BaseUnit) obj;
+		if (measure == null) {
+			if (other.measure != null) {
+				return false;
+			}
+		} else if (!measure.equals(other.measure)) {
+			return false;
+		}
+		if (name == null) {
+			if (other.name != null) {
+				return false;
+			}
+		} else if (!name.equals(other.name)) {
+			return false;
+		}
+		if (shortName == null) {
+			if (other.shortName != null) {
+				return false;
+			}
+		} else if (!shortName.equals(other.shortName)) {
+			return false;
+		}
+		if (Double.doubleToLongBits(value) != Double.doubleToLongBits(other.value)) {
+			return false;
+		}
+		return true;
+	}
+
+	/**
+	 * Returns the string representation of this unit in the form:
+	 * 
+	 * BaseUnit [measure=Measure [name=length], value=1000.0, name=kilometer,
+	 * shortName=km]
+	 * 
+	 */
+
+	@Override
+	public String toString() {
+		StringBuilder builder = new StringBuilder();
+		builder.append("BaseUnit [measure=");
+		builder.append(measure);
+		builder.append(", value=");
+		builder.append(value);
+		builder.append(", name=");
+		builder.append(name);
+		builder.append(", shortName=");
+		builder.append(shortName);
+		builder.append("]");
+		return builder.toString();
+	}
+
+	/**
+	 * Returns the ComposedUnit formed from this base unit.
+	 */
+	public ComposedUnit asComposedUnit() {
+		return ComposedUnit.builder().setBaseUnit(this, 1).build();
+
+	}
+
+}