ebean/src/test/java/com/avaje/tests/model/ivo/Rate.java

package com.avaje.tests.model.ivo;


import java.io.Serializable;
import java.math.BigDecimal;
import java.math.MathContext;

/**
 * A representation of a Rate (like Tax or Discount) that is typically
 * used to multiple against an amount (like Money).
 * <p>
 * A Rate effectively wraps a BigDecimal with associated control over
 * precision and scale.
 * <p>
 * Rates are typically used to multiple or divide against an amount.
 * For example, you can't ADD a Rate to Money.
 * </p>
 *
 * @author rbygrave
 */
public final class Rate implements Comparable<Rate>, Serializable {

  private static final long serialVersionUID = 1L;

  public static final Rate ZERO = new Rate(BigDecimal.ZERO);
  public static final Rate ONE = new Rate(BigDecimal.ONE);

  private final BigDecimal value;

  public Rate(BigDecimal value) {
    if (value == null) {
      throw new NullPointerException("value can not be null");
    }
    this.value = value;
  }

  public Rate(double val) {
    this(BigDecimal.valueOf(val));
  }

  public Rate(String val) {
    this(new BigDecimal(val));
  }

  public String toString() {
    return value.toString();
  }

  public int compareTo(Rate o) {
    return value.compareTo(o.value);
  }

  @Override
  public int hashCode() {
    return value.hashCode();
  }

  @Override
  public boolean equals(Object obj) {
    if (obj instanceof Rate) {
      // use BigDecimal.compareTo to handle scale differences
      return value.compareTo(((Rate) obj).getValue()) == 0;
    }
    return false;
  }

  public BigDecimal getValue() {
    return value;
  }

  public Rate subtract(Rate amt) {
    BigDecimal b = value.subtract(amt.value);
    return new Rate(b);
  }

  public Rate subtract(Rate amt, MathContext ctx) {
    BigDecimal b = value.subtract(amt.value, ctx);
    return new Rate(b);
  }

  public Rate add(Rate amt) {
    BigDecimal b = value.add(amt.value);
    return new Rate(b);
  }

  public Rate add(Rate amt, MathContext ctx) {
    BigDecimal b = value.add(amt.value, ctx);
    return new Rate(b);
  }

  /**
   * A Rate times Money amount returns Money.
   */
  public Money times(Money amount) {
    return multiply(amount);
  }

  public Money multiply(Money amount) {
    BigDecimal b = value.multiply(amount.getAmount());
    return new Money(b);
  }

  public Rate multiply(Rate m) {
    return multiply(m.value);
  }

  public Rate multiply(int val) {
    return multiply(BigDecimal.valueOf(val));
  }

  public Rate multiply(float val) {
    return multiply(BigDecimal.valueOf(val));
  }

  public Rate multiply(double val) {
    return multiply(BigDecimal.valueOf(val));
  }

  public Rate multiply(BigDecimal m) {
    BigDecimal b = value.multiply(m);
    return new Rate(b);
  }

  public Rate divide(BigDecimal divisor) {
    BigDecimal b = value.divide(divisor);
    return new Rate(b);
  }

  public Rate divide(BigDecimal divisor, MathContext ctx) {
    BigDecimal b = value.divide(divisor, ctx);
    return new Rate(b);
  }

}