Objects and Classes - Types - Datatypes

5 important questions on Objects and Classes - Types - Datatypes

Having just these few primitive types and enumerations to use is very limited.

UML offers up the ability to build additional types based on the primitives. These look like classes.

What are they?


What is the keyword for Datatypes?


In Fig. 6.7, we show two dataTypes that we have constructed.

What does the " + "  means?

We also used the “+,” public visibility, to indicate that the properties and operations of the dataType are visible outside of the dataType.
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What are the operations in the figure?

We have also added some operations to the Date datatType, to support adding days to the current date, and for comparing dates.

The first operation addToDate(days:Integer) doesn’t need a return type, because it updates the Date dataType value in place.

To the right and in Fig. 6.8, we use the formal format.

{year > 1910}.

{month ≥ 1 and month ≤ 12}

{day in 1 … 31}

The “..” is the standard way the UML represents an INTERVAL, from low to high. 

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