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Multiplicity - Multiplicity Properties and Collection Types - Sequence

Q: ..... and ...... collections are common. What two collections are common?

Ordered and nonUnique collections are common.

5 important questions on Multiplicity - Multiplicity Properties and Collection Types - Sequence

Give an example of "Sequence" in the Ride system.

In the operation Ride.Schedule() as shown in Fig. 10.8, we have a multivalued argument itinerary (reisroute).

The itinerary is a set of locations that the ride must visit.

These have a natural order, the first stop, the second stop, … the last stop.

However, there is no reason why the ride cannot visit some of the same stops more than once (Fig. 10.11).

..... and ...... collections are common.

What two collections are common?

Ordered and nonUnique collections are common.

Can you give an example of a "Ordere" but "noUnique" collection?

For example:

consider sampling the barometric pressure at a location every day at the same time.

The results are ordered, but we allow duplicate measurements values. Similarly, consider the closing values of the stock market over time.

As they are common, it is convenient to refer to them by their collection name of SEQUENCE or SEQ.

What is the term {stream} ?

Occasionally, one may see the term {stream} used instead of {sequence}.

Though streams may be sequences, the term stream primarily describes how the elements arrive over time.

Multiplicity Properties (Modified from UML 2.5 specification Table 7.1)

The term “bag” is a common name for collections that allow duplicate entries and is the term used within UML. In mathematics, they are also called multisets.