Hook: Define New Type Of Value

Requirement

A new type of value is needed that is not supported by the Framework.

Method of Adaptation

Add Feature

Level of Support

Open Ended

HotSpot

Data management

Participants

Value, NewValue

Changes

1. implementation NewValue of Value.
2. NewValue implements the four basic arithmetic operations addition, multiplication, subtraction and division.
3. NewValue.compareTo implements Value.compareTo .
4. NewValue.clone implements Value.clone .
5. NewValue adds any attributes that are needed or appropriate for the new type of value.
6. NewValue implements any additional methods that are needed or appropriate for the new type of value.

Constraints

• NewValue must form at least a commutative monoid with respect to addition/subtraction and to multiplication/division.

  The neutral element must return true from data.Value.isAddZero and data.Value.isMulOne , resp. The neutral element of an algebraic structure A = (M, +) is the element e from M for which for all a from M a + e = e + a = a .

  The zero element with respect to multiplication must return true from data.Value.isMulZero . The zero element with respect to multiplication is the value z for which for all values a a * z = z * a = z

Comments

• The Framework provides a limited, but for common cases probably sufficient, range of types of values:
  • data.NumberValue represents numeric values, concrete subclasses provided are:
    • data.IntegerValue a whole number of normal int range.
    • data.DoubleValue a number of normal double range and precision.
  • data.QuoteValue is a combination of two values of the same type. It can be used to save bids and offers , i.e. buy and sell prices.