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18 Cards in this Set
- Front
- Back
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attributes |
listed in a class diagram indicating which properties of the class are important, but no values are shown - the middle part of the class box is used to record these attributes |
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associations |
- connections that provide the glue to hold the classes together - if the concepts are sufficiently important to exist in a structural model then any relationship between them should be modelled - object models are useful for deciding what associations should be added to the class model |
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multiplicities |
- represent how many objects are related to an other object - 1 exactly 1 - 3..5 between 3 and 5, inclusive - 1..* one or more - 7,12,365 7,12and 365 and no other - * same as 0..* - by stating multiplicity at one end of an association you are saying how many instances of the class, at that end can be linked with a single instance of the class at the other end |
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association names and role names |
- UML provides 2 mechanisms for naming associations: - placing an association name in the middle of the association lines - using role names |
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navigation expressions |
- used for this kind if notation, in which you name an object or object attribute by starting at some objectand then hopping from that object to another, following a path - they are naming conventions - you start at one object and then use role names to identify the next object or attribute jack.currentRoom.floor |
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several associations between a pair of classes |
- there can be more than one association between any 2 classes - you need to include them all - associations representing relationships not implementations |
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recursive associations |
associations between the class and itself |
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aggregation |
- a type of association where there is a whole-part relationship between classes, in which case it would be possible to add, remove or replace one of the parts and still have a meaningful relationship - they have to be free of cycle |
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composition |
- the composed objects are part of the composing object - if the composing object is deleted, all of the composed objects must be deleted too |
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navigability |
- an arrowhead indicates that it is possible to reach one class from another following the direction of the arrow - this way you restricting access to instances of the class at the end of the association where you placed the arrowhead - if you put no arrowheads on the associations, navigability in both directions is assumed - mainly used during implementation when to decide how to write the code |
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qualified associations |
- a unique qualifier is represented at the far end of the association from the class that the qualifier is an attribute of - they often replace an association having multiplicity of * with one having of either 1 or 0..1 - it tells you about the property of the concept that relates the classes at the ends of the asociation |
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association class |
- it has properties of its own and it becomes a first-class citizen - it also imposes a restriction that there can be at most one instance of the association class per pair of objects linked to the association |
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derived associations |
- used to add an association to the model for understanding it, but the association is not necessary because other associations in the model can be combined to achieve the same navigation - / simbol of derived attribution |
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generalisation |
the generalised version of the class |
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specialisation |
the specialised version of the class |
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substitutability |
a more specialised element can be substituted (replaced) for a less specialised element in the same hierarchy |
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interfaces |
- a set of operations that specify the service that the class provides - the interface of the subclass always contains the interface of the superclass - there are no mechanisms for removing operations -however, subclasses can refine operations that are in a superclass |
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specialisation and subtitutability |
- the substitutability test can indicate whether a use of specialisation is correct - use specialisation only when an instance of a sublass is substitutable for an arbitrary (unrestrained) instance of a superclass |
