Class hierarchy

Figure 11.6 illustrates this approach. Although this example focuses on a single class hierarchy, it extends to the set of collaborating abstract classes that are characteristic of frameworks. 

The basic idea of plugging in to a code framework shows up in different ways in different languages, including C++ templates, component/connector technologies, and class hierarchies. The latter tend to be overused it is often better to replace the inheritance with composition and explicit forwarding and to use types to document the subtle call patterns between superclasses and subclasses. 

There are different types of code reuse. Here we focus on code reuse using a class hierarchy—in other words, through inheritance. 

Notice that now each of these two classes extends Molstructure class and all common code is removed from them. This result is because the common behaviors are inherited from the common superclass—Molstructure. Also notice that even some logic in the constructor is inherited from the superclass. Now we have achieved some code reuse through inheritance by having a class hierarchy. 

At the very top of Figure 12.15 is an abstract class Lsi. Lsi is the base class of all concrete Lsi classes—Parent ID, Compound ID and Sample ID. All of its methods are declared abstract. It defines common interfaces of the component and composite in the Lsi class hierarchy. Parent ID is the smallest possible unit and therefore is a component. Both Compound ID and Sample ID can have another type of Lsi as a component and therefore are composites. The source code of the abstract base class Lsi is as follows ... 

CompositeLsi is an abstract superclass of CompoundID and SamplelD classes. It is the abstract composite in the LSI class hierarchy ... 

On the model level, we distinguish between a type (or class) level and an instance level, like standard UML does. On the type level, document models for specific types of documents are defined. They are expressed as class hierarchies describing the documents underlying type systems. In our example, documents containing simulation models for Aspen Plus and flowsheets for Comos PT are defined. To be able to perform an integration of these documents, link types that relate classes contained in the documents class hierarchies are defined. All occurrences of links in further definitions on lower levels are instances of these link tjqjes and are thereby constrained by these types. 

A Class Hierarchy diagram showing the relationship between the various entities in the object-oriented knowledge base is shown in Figure 1. Each entity is implemented as a class in C+-h For example the object Quantity represents the attributes common to all scientific quantities. Each instance of a class represents a real-world object, for example Force is an instance of Quantity and Newton is an instance of the class Unit. 

Every database schema, every class hierarchy, every ontology embodies an implicit candidate for standards. Here we list only the entities concentrating on developing standard representations explicitly for pathway data. 

Polymorphism Allows us to send the same message to different objects in different levels of class hierarchy. Each object responds in a way that is inherited or redefined with respect to the object s characteristics. 

Figures. Class hierarchy of inplemented MCA methods. Figure 4. RC circuit-breaker (Recloser) on the pole.

Fokin, A., Troshina, K. Chernov, A. (2010). Reconstruction of class hierarchies for decompilation of C++ programs, 14th IEEE European Conference on Software Maintenance and Reengineering (CSMRTO) pp. 240-243. 

Structural part. Here, all the available operators are characterised. In addition to the primitive HBBs (see physical part), we consider two other types of operators abstract building blocks (ABBs) and predefined EXUs/ASUs. These two types can be associated with abstraction hierarchy and architectural hierarchy respectively. Abstraction hierarchy is similar to class hierarchy in the object-oriented programming sense the operators are classified in a lattice, in which the ABBs are used at several levels of abstraction to represent... 

Fig. 12.6 The GUI of the requirement management system. The left part of the display shows the Requirements class hierarchy. The upper part shows a list of all variables involved in the constraint system. Each variable is associated to an attribute of a class. The bottom-left window shows a list of the constraints in the constraint system. The bottom-right panel shows a list of the constraints which are in conflict after executing the consistency checking...

Subsumption identifies, whether class hierarchies exist. In our example, the class hierarchy Sensor SubCIassOf Component and Actuator SubClassOf Component can be inferred from axioms (1) and (2). 

Figure 2 Multiple inheritance in a class hierarchy provides additional design flexibility...

We have not included any attributes in a molecule to store its name or list of names. Clearly, it would be desirable to store both a common, short name as well as a systematic name for a molecule it would also be desirable to allow for additional names, and provide methods to manipulate these attributes. In our OOP representation of biochemical systems, we will provide a generic mechanism which relies on a superclass called named object . Then, all we need to do is designate the named object as a superclass of molecules all the attributes and methods are then automatically inherited. This is an example of software reuse facilitated by OOP. Once we abstract a very generic behavior in one system, we can use that same behavior in many other systems, through the class hierarchy and multiple inheritance mechanisms of OOP. 

Figure 8-2 shows the relationships between the different entities of the physical data model that represents the plant physical structure. In this figure, plant equipment class specifications are represented in equipmentspec , while the equipment records are represented in equipment . Similarly for spare parts, itemspec is used to specify the class specifications while item is used to describe the spare parts instances i.e. objects. The specifications of the class hierarchy are represented in classstructure , classspec , and assetattribute . 

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