measurement.java

OSGI这是一个中间件,与UPNP齐名,是用于移植到嵌入式平台之上

	/**
	 * Returns a new <tt>Measurement</tt> object that is the quotient
	 * of this object divided by the specified value.
	 *
	 * @param d The value that will be the divisor of
	 * this object.
	 * @return A new <tt>Measurement</tt> object that is the quotient
	 * of this object divided by the specified value.
	 * The error of the new object is computed.
	 * The unit and time of the new object is set to the
	 * <tt>Unit</tt> and time of this object.
	 */
	public Measurement div(double d)
	{
		return new Measurement(value / d, error / Math.abs(d), unit, time);
	}

	/**
	 * Returns a new <tt>Measurement</tt> object that is the sum
	 * of this object added to the specified object.
	 *
	 * The error and unit of the new object are computed.
	 * The time of the new object is set to the time of this object.
	 *
	 * @param m The <tt>Measurement</tt> object that will be added with
	 * this object.
	 * @return A new <tt>Measurement</tt> object that is the sum of this and m.
	 * @see Unit
	 * @throws ArithmeticException If the <tt>Unit</tt> objects
	 * of this object and the specified object cannot be added.
	 */
	public Measurement add(Measurement m)
	{
		return new Measurement(value + m.value, error + m.error, unit.add(m.unit), time);
	}

	/**
	 * Returns a new <tt>Measurement</tt> object that is the sum
	 * of this object added to the specified value.
	 *
	 * @param d The value that will be added with
	 * this object.
	 * @param u The <tt>Unit</tt> object of the specified value.
	 * @return A new <tt>Measurement</tt> object that is the sum
	 * of this object added to the specified value.
	 * The unit of the new object is computed.
	 * The error and time of the new object is set to the
	 * error and time of this object.
	 * @throws ArithmeticException If the <tt>Unit</tt> objects
	 * of this object and the specified value cannot be added.
	 * @see Unit
	 */
	public Measurement add(double d, Unit u)
	{
		return new Measurement(value + d, error, unit.add(u), time);
	}

	/**
	 * Returns a new <tt>Measurement</tt> object that is the sum
	 * of this object added to the specified value.
	 *
	 * @param d The value that will be added with
	 * this object.
	 * @return A new <tt>Measurement</tt> object that is the sum
	 * of this object added to the specified value.
	 * The error, unit, and time of the new object is set to the
	 * error, <tt>Unit</tt> and time of this object.
	 */
	public Measurement add(double d)
	{
		return new Measurement(value + d, error, unit, time);
	}

	/**
	 * Returns a new <tt>Measurement</tt> object that is the subtraction
	 * of the specified object from this object.
	 *
	 * @param m The <tt>Measurement</tt> object that will be subtracted from
	 * this object.
	 * @return A new <tt>Measurement</tt> object that is the subtraction
	 * of the specified object from this object.
	 * The error and unit of the new object are computed.
	 * The time of the new object is set to the time of this object.
	 * @throws ArithmeticException If the <tt>Unit</tt> objects
	 * of this object and the specified object cannot be subtracted.
	 * @see Unit
	 */
	public Measurement sub(Measurement m)
	{
		return new Measurement(value - m.value, error + m.error, unit.sub(m.unit), time);
	}

	/**
	 * Returns a new <tt>Measurement</tt> object that is the subtraction
	 * of the specified value from this object.
	 *
	 * @param d The value that will be subtracted from
	 * this object.
	 * @param u The <tt>Unit</tt> object of the specified value.
	 * @return A new <tt>Measurement</tt> object that is the subtraction
	 * of the specified value from this object.
	 * The unit of the new object is computed.
	 * The error and time of the new object is set to the
	 * error and time of this object.
	 * @throws ArithmeticException If the <tt>Unit</tt> objects
	 * of this object and the specified object cannot be subtracted.
	 * @see Unit
	 */
	public Measurement sub(double d, Unit u)
	{
		return new Measurement(value - d, error, unit.sub(u), time);
	}

	/**
	 * Returns a new <tt>Measurement</tt> object that is the subtraction
	 * of the specified value from this object.
	 *
	 * @param d The value that will be subtracted from
	 * this object.
	 * @return A new <tt>Measurement</tt> object that is the subtraction
	 * of the specified value from this object.
	 * The error, unit and time of the new object is set to the
	 * error, <tt>Unit</tt> object and time of this object.
	 */
	public Measurement sub(double d)
	{
		return new Measurement(value - d, error, unit, time);
	}

	/**
	 * Returns a <tt>String</tt> object representing this <tt>Measurement</tt> object.
	 *
	 * @return a <tt>String</tt> object representing this <tt>Measurement</tt> object.
	 */
	public String toString()
	{
		if (name == null)
		{
			StringBuffer sb = new StringBuffer();

			sb.append(value);

			if (error != 0.0d)
			{
				sb.append(" +/- ");
				sb.append(error);
			}

			String u = unit.toString();
			if (u.length() > 0)
			{
				sb.append(" ");
				sb.append(u);
			}

			name = sb.toString();
		}

		return name;
	}

	/**
	 * Compares this object with the specified object for order.  Returns a
	 * negative integer, zero, or a positive integer if this object is less
	 * than, equal to, or greater than the specified object.
	 *
	 * <p>Note: This class has a natural ordering that is
	 * inconsistent with equals. For this method, another <tt>Measurement</tt>
	 * object is considered equal if there is some <tt>x</tt> such that
	 * <pre>
	 * 	getValue()-getError() <= x <= getValue()+getError()
	 * </pre>
	 * for both <tt>Measurement</tt> objects being compared.
	 *
	 * @param   obj The object to be compared.
	 * @return  A negative integer, zero, or a positive integer if this object
	 *		is less than, equal to, or greater than the specified object.
	 *
	 * @throws ClassCastException If the specified object is not of type <tt>Measurement</tt>.
	 * @throws ArithmeticException If the unit of the specified <tt>Measurement</tt> object is
	 * not equal to the <tt>Unit</tt> object of this object.
	 */
	public int compareTo(Object obj)
	{
		if (this == obj)
		{
			return 0;
		}

		Measurement that = (Measurement) obj;

		if (!unit.equals(that.unit))
		{
			throw new ArithmeticException( "Cannot compare " + this + " and " + that);
		}

		if (value == that.value)
		{
			return 0;
		}

		if (value < that.value)
		{
			if ((value + error) >= (that.value - that.error))
			{
				return 0;
			}
			else
			{
				return -1;
			}
		}
		else
		{
			if ((value - error) <= (that.value + that.error))
			{
				return 0;
			}
			else
			{
				return 1;
			}
		}
	}

	/**
	 * Returns a hash code value for this object.
	 *
	 * @return A hash code value for this object.
	 */
	public int hashCode()
	{
		long bits = Double.doubleToLongBits(value + error);

		return ((int)(bits ^ (bits >>> 32))) ^ unit.hashCode();
	}

	/**
	 * Returns whether the specified object is equal to this object.
	 * Two <tt>Measurement</tt> objects are equal if they have same value,
	 * error and <tt>Unit</tt>.
	 *
	 * <p>Note: This class has a natural ordering that is
	 * inconsistent with equals. See {@link #compareTo}.
	 *
	 * @param obj The object to compare with this object.
	 * @return <tt>true</tt> if this object is equal to the specified
	 * object; <tt>false</tt> otherwise.
	 */
	public boolean equals(Object obj)
	{
		if (this == obj)
		{
			return true;
		}

		if (!(obj instanceof Measurement))
		{
			return false;
		}

		Measurement that = (Measurement)obj;

		return (value == that.value) && (error == that.error) && unit.equals(that.unit);
	}
}