Category: uml

UML – Knowledge Test ”; Previous Next This chapter list down simple questions on UML concepts you just have gone through this tutorial. Based on the given set of questions you can assess yourself to build a good confidence to become an UML expert: Can a class diagram show the dynamic behaviour of a system? Can deployment diagram be used for forward and reverse engineering? Can it be used for forward and reverse engineering? Can it represent parallel flow of activities? Can we convert statechart diagram to activity diagram? Can we use forward engineering in component diagram? Can we use the use case diagram for forward and reverse engineering? Describe the purpose of use case diagram? How object oriented concepts are related to UML? Is component diagram representing the dynamic view of a system? Name major building blocks of UML? Name some scenarios where object diagrams are used? Name the three mechanisms in stereotype? What are the artifacts of a deployment diagram? What are the artifacts used to make a component diagram? What are the different UML diagrams? What are the different elements of a use case diagram? What are the different modeling used in UML? What are the elements of an object diagram? What are the goals of UML? What are the main usages of a deployment diagram? What are the notations used in behavioural things? What are the notations used in relationships? What are the notations used in structural things? What are the other four diagrams used in UML for capturing dynamic behaviour of a system? What are the structural diagrams and behavioural diagrams? What are the usages of sequence and collaboration diagram? What do you mean by dynamic behaviour of a system? What does an object diagram capture? What is OO analysis? What is OO design? What is a Statechart diagram? What is a class diagram? What is a constraint rule? What is a deployment diagram? What is a node? What is a reactive system? What is a state? What is a use case diagram? What is an activity diagram? What is an event and how it influences the states of an object? What is an interaction diagram? What is an object diagram? What is collaboration diagram? What is component diagram? What is composition and aggregation? What is difference between analysis and design? What is generalization and when it is used? What is meant by isomorphic? What is responsibility of an object? What is role of UML in OO analysis and design? What is sequence diagram? What is static and dynamic view of a system? What is structural diagram? What is the difference between a class diagram and an object diagram? What is the difference between a flow chart and an activity diagram? What is the difference between aggregation and composition? What is the difference between sequence and collaboration diagram? What is the interaction diagrams used in UML? What is the main usage of a Statechart diagram? What is the main usage of an activity diagram? What is the only grouping thing available in UML? Why conceptual model is important? Why statechart diagram us used? Print Page Previous Next Advertisements ”;

UML – Overview ”; Previous Next UML is a standard language for specifying, visualizing, constructing, and documenting the artifacts of software systems. UML was created by the Object Management Group (OMG) and UML 1.0 specification draft was proposed to the OMG in January 1997. OMG is continuously making efforts to create a truly industry standard. UML stands for Unified Modeling Language. UML is different from the other common programming languages such as C++, Java, COBOL, etc. UML is a pictorial language used to make software blueprints. UML can be described as a general purpose visual modeling language to visualize, specify, construct, and document software system. Although UML is generally used to model software systems, it is not limited within this boundary. It is also used to model non-software systems as well. For example, the process flow in a manufacturing unit, etc. UML is not a programming language but tools can be used to generate code in various languages using UML diagrams. UML has a direct relation with object oriented analysis and design. After some standardization, UML has become an OMG standard. Goals of UML A picture is worth a thousand words, this idiom absolutely fits describing UML. Object-oriented concepts were introduced much earlier than UML. At that point of time, there were no standard methodologies to organize and consolidate the object-oriented development. It was then that UML came into picture. There are a number of goals for developing UML but the most important is to define some general purpose modeling language, which all modelers can use and it also needs to be made simple to understand and use. UML diagrams are not only made for developers but also for business users, common people, and anybody interested to understand the system. The system can be a software or non-software system. Thus it must be clear that UML is not a development method rather it accompanies with processes to make it a successful system. In conclusion, the goal of UML can be defined as a simple modeling mechanism to model all possible practical systems in today’s complex environment. A Conceptual Model of UML To understand the conceptual model of UML, first we need to clarify what is a conceptual model? and why a conceptual model is required? A conceptual model can be defined as a model which is made of concepts and their relationships. A conceptual model is the first step before drawing a UML diagram. It helps to understand the entities in the real world and how they interact with each other. As UML describes the real-time systems, it is very important to make a conceptual model and then proceed gradually. The conceptual model of UML can be mastered by learning the following three major elements − UML building blocks Rules to connect the building blocks Common mechanisms of UML Object-Oriented Concepts UML can be described as the successor of object-oriented (OO) analysis and design. An object contains both data and methods that control the data. The data represents the state of the object. A class describes an object and they also form a hierarchy to model the real-world system. The hierarchy is represented as inheritance and the classes can also be associated in different ways as per the requirement. Objects are the real-world entities that exist around us and the basic concepts such as abstraction, encapsulation, inheritance, and polymorphism all can be represented using UML. UML is powerful enough to represent all the concepts that exist in object-oriented analysis and design. UML diagrams are representation of object-oriented concepts only. Thus, before learning UML, it becomes important to understand OO concept in detail. Following are some fundamental concepts of the object-oriented world − Objects − Objects represent an entity and the basic building block. Class − Class is the blue print of an object. Abstraction − Abstraction represents the behavior of an real world entity. Encapsulation − Encapsulation is the mechanism of binding the data together and hiding them from the outside world. Inheritance − Inheritance is the mechanism of making new classes from existing ones. Polymorphism − It defines the mechanism to exists in different forms. OO Analysis and Design OO can be defined as an investigation and to be more specific, it is the investigation of objects. Design means collaboration of identified objects. Thus, it is important to understand the OO analysis and design concepts. The most important purpose of OO analysis is to identify objects of a system to be designed. This analysis is also done for an existing system. Now an efficient analysis is only possible when we are able to start thinking in a way where objects can be identified. After identifying the objects, their relationships are identified and finally the design is produced. The purpose of OO analysis and design can described as − Identifying the objects of a system. Identifying their relationships. Making a design, which can be converted to executables using OO languages. There are three basic steps where the OO concepts are applied and implemented. The steps can be defined as OO Analysis → OO Design → OO implementation using OO languages The above three points can be described in detail as − During OO analysis, the most important purpose is to identify objects and describe them in a proper way. If these objects are identified efficiently, then the next job of design is easy. The objects should be identified with responsibilities. Responsibilities are the functions performed by the object. Each and every object has some type of responsibilities to be performed. When these responsibilities are collaborated, the purpose of the system is fulfilled. The second phase is OO design. During this phase, emphasis is placed on the requirements and their fulfilment. In this stage, the objects are collaborated according to their intended association. After the association is complete, the design is also complete. The third phase is OO implementation. In this phase, the design is implemented using OO languages such as Java, C++, etc. Role of UML

UML – Object Diagrams ”; Previous Next Object diagrams are derived from class diagrams so object diagrams are dependent upon class diagrams. Object diagrams represent an instance of a class diagram. The basic concepts are similar for class diagrams and object diagrams. Object diagrams also represent the static view of a system but this static view is a snapshot of the system at a particular moment. Object diagrams are used to render a set of objects and their relationships as an instance. Purpose of Object Diagrams The purpose of a diagram should be understood clearly to implement it practically. The purposes of object diagrams are similar to class diagrams. The difference is that a class diagram represents an abstract model consisting of classes and their relationships. However, an object diagram represents an instance at a particular moment, which is concrete in nature. It means the object diagram is closer to the actual system behavior. The purpose is to capture the static view of a system at a particular moment. The purpose of the object diagram can be summarized as − Forward and reverse engineering. Object relationships of a system Static view of an interaction. Understand object behaviour and their relationship from practical perspective How to Draw an Object Diagram? We have already discussed that an object diagram is an instance of a class diagram. It implies that an object diagram consists of instances of things used in a class diagram. So both diagrams are made of same basic elements but in different form. In class diagram elements are in abstract form to represent the blue print and in object diagram the elements are in concrete form to represent the real world object. To capture a particular system, numbers of class diagrams are limited. However, if we consider object diagrams then we can have unlimited number of instances, which are unique in nature. Only those instances are considered, which have an impact on the system. From the above discussion, it is clear that a single object diagram cannot capture all the necessary instances or rather cannot specify all the objects of a system. Hence, the solution is − First, analyze the system and decide which instances have important data and association. Second, consider only those instances, which will cover the functionality. Third, make some optimization as the number of instances are unlimited. Before drawing an object diagram, the following things should be remembered and understood clearly − Object diagrams consist of objects. The link in object diagram is used to connect objects. Objects and links are the two elements used to construct an object diagram. After this, the following things are to be decided before starting the construction of the diagram − The object diagram should have a meaningful name to indicate its purpose. The most important elements are to be identified. The association among objects should be clarified. Values of different elements need to be captured to include in the object diagram. Add proper notes at points where more clarity is required. The following diagram is an example of an object diagram. It represents the Order management system which we have discussed in the chapter Class Diagram. The following diagram is an instance of the system at a particular time of purchase. It has the following objects. Customer Order SpecialOrder NormalOrder Now the customer object (C) is associated with three order objects (O1, O2, and O3). These order objects are associated with special order and normal order objects (S1, S2, and N1). The customer has the following three orders with different numbers (12, 32 and 40) for the particular time considered. The customer can increase the number of orders in future and in that scenario the object diagram will reflect that. If order, special order, and normal order objects are observed then you will find that they have some values. For orders, the values are 12, 32, and 40 which implies that the objects have these values for a particular moment (here the particular time when the purchase is made is considered as the moment) when the instance is captured The same is true for special order and normal order objects which have number of orders as 20, 30, and 60. If a different time of purchase is considered, then these values will change accordingly. The following object diagram has been drawn considering all the points mentioned above Where to Use Object Diagrams? Object diagrams can be imagined as the snapshot of a running system at a particular moment. Let us consider an example of a running train Now, if you take a snap of the running train then you will find a static picture of it having the following − A particular state which is running. A particular number of passengers. which will change if the snap is taken in a different time Here, we can imagine the snap of the running train is an object having the above values. And this is true for any real-life simple or complex system. In a nutshell, it can be said that object diagrams are used for − Making the prototype of a system. Reverse engineering. Modeling complex data structures. Understanding the system from practical perspective. Print Page Previous Next Advertisements ”;

UML 2.0 – Overview ”; Previous Next UML 2.0 is totally a different dimension in the world of Unified Modeling Language. It is more complex and extensive in nature. The extent of documentation has also increased compared to UML 1.5 version. UML 2.0 has added new features so that its usage can be more extensive. UML 2.0 adds the definition of formal and completely defined semantics. This new possibility can be utilized for the development of models and the corresponding systems can be generated from these models. However, to utilize this new dimension, a considerable effort has to be made to acquire knowledge. New Dimensions in UML 2.0 The structure and documentation of UML was completely revised in the latest version of UML 2.0. There are now two documents available that describe UML − UML 2.0 Infrastructure defines the basic constructs of the language on which UML is based. This section is not directly relevant to the users of UML. This is directed more towards the developers of modeling tools. This area is not in the scope of this tutorial. UML 2.0 Superstructure defines the user constructs of UML 2.0. It means those elements of UML that the users will use at the immediate level. This is the main focus for the user community of UML. This revision of UML was created to fulfil a goal to restructure and refine UML so that usability, implementation, and adaptation are simplified. UML infrastructure is used to − Provide a reusable meta-language core. This is used to define UML itself. Provide mechanisms to adjustment the language. UML superstructure is used to − Provide better support for component-based development. Improve constructs for the specification of architecture. Provide better options for the modeling of behavior. The important point to note is the major divisions described above. These divisions are used to increase the usability of UML and define a clear understanding of its usage. There is another dimension which is already proposed in this new version. It is a proposal for a completely new Object Constraint Language (OCL) and Diagram Interchange. These features all together form the complete UML 2.0 package. Modeling Diagrams in UML 2.0 Modeling Interactions The interaction diagrams described in UML 2.0 is different than the earlier versions. However, the basic concept remains the same as the earlier version. The major difference is the enhancement and additional features added to the diagrams in UML 2.0. UML 2.0 models object interaction in the following four different ways. Sequence diagram is a time dependent view of the interaction between objects to accomplish a behavioral goal of the system. The time sequence is similar to the earlier version of sequence diagram. An interaction may be designed at any level of abstraction within the system design, from subsystem interactions to instancelevel. Communication diagram is a new name added in UML 2.0. Communication diagram is a structural view of the messaging between objects, taken from the Collaboration diagram concept of UML 1.4 and earlier versions. This can be defined as a modified version of collaboration diagram. Interaction Overview diagram is also a new addition in UML 2.0. An Interaction Overview diagram describes a high-level view of a group of interactions combined into a logic sequence, including flow-control logic to navigate between the interactions. Timing diagram is also added in UML 2.0. It is an optional diagram designed to specify the time constraints on the messages sent and received in the course of an interaction. From the above description, it is important to note that the purpose of all the diagrams are to send/receive messages. The handling of these messages are internal to the objects. Hence, the objects also have options to receive and send messages, and here comes another important aspect called interface. Now these interfaces are responsible for accepting and sending messages to one another. It can thus be concluded that the interactions in UML 2.0 are described in a different way and that is the reason why the new diagram names have come into picture. If we analyze the new diagrams then it is clear that all the diagrams are created based upon the interaction diagrams described in the earlier versions. The only difference is the additional features added in UML 2.0 to make the diagrams more efficient and purpose oriented. Modeling Collaborations As we have already discussed, collaboration is used to model common interactions between objects. We can say that collaboration is an interaction where a set of messages are handled by a set of objects having pre-defined roles. The important point to note is the difference between the collaboration diagram in the earlier version and in UML 2.0 version. To distinguish, the name of the collaboration diagram has been changed in UML 2.0. In UML 2.0, it is named as Communication diagram. Consequently, collaboration is defined as a class with attributes (properties) and behavior (operations). Compartments on the collaboration class can be user defined and may be used for interactions (Sequence diagrams) and structural elements (Composite Structure diagram). Following figure models the Observer design pattern as collaboration between an object in the role of an observable item and any number of objects as the observers. Modeling Communication Communication diagram is slightly different than the collaboration diagrams of the earlier versions. We can say it is a scaled back version of the earlier UML versions. The distinguishing factor of the communication diagram is the link between objects. This is a visual link and it is missing in the sequence diagram. In the sequence diagram, only the messages passed between the objects are shown even if there is no link between them. Communication diagram is used to prevent the modeler from making this mistake by using an Object diagram format as the basis for messaging. Each object on a Communication diagram is called an object lifeline. The message types in a Communication diagram are the same as in a Sequence diagram. Communication diagram may model synchronous, asynchronous, return, lost, found, a

UML – Architecture ”; Previous Next Any real-world system is used by different users. The users can be developers, testers, business people, analysts, and many more. Hence, before designing a system, the architecture is made with different perspectives in mind. The most important part is to visualize the system from the perspective of different viewers. The better we understand the better we can build the system. UML plays an important role in defining different perspectives of a system. These perspectives are − Design Implementation Process Deployment The center is the Use Case view which connects all these four. A Use Case represents the functionality of the system. Hence, other perspectives are connected with use case. Design of a system consists of classes, interfaces, and collaboration. UML provides class diagram, object diagram to support this. Implementation defines the components assembled together to make a complete physical system. UML component diagram is used to support the implementation perspective. Process defines the flow of the system. Hence, the same elements as used in Design are also used to support this perspective. Deployment represents the physical nodes of the system that forms the hardware. UML deployment diagram is used to support this perspective. Print Page Previous Next Advertisements ”;

UML – Building Blocks ”; Previous Next As UML describes the real-time systems, it is very important to make a conceptual model and then proceed gradually. The conceptual model of UML can be mastered by learning the following three major elements − UML building blocks Rules to connect the building blocks Common mechanisms of UML This chapter describes all the UML building blocks. The building blocks of UML can be defined as − Things Relationships Diagrams Things Things are the most important building blocks of UML. Things can be − Structural Behavioral Grouping Annotational Structural Things Structural things define the static part of the model. They represent the physical and conceptual elements. Following are the brief descriptions of the structural things. Class − Class represents a set of objects having similar responsibilities. Interface − Interface defines a set of operations, which specify the responsibility of a class. Collaboration −Collaboration defines an interaction between elements. Use case −Use case represents a set of actions performed by a system for a specific goal. Component −Component describes the physical part of a system. Node − A node can be defined as a physical element that exists at run time. Behavioral Things A behavioral thing consists of the dynamic parts of UML models. Following are the behavioral things − Interaction − Interaction is defined as a behavior that consists of a group of messages exchanged among elements to accomplish a specific task. State machine − State machine is useful when the state of an object in its life cycle is important. It defines the sequence of states an object goes through in response to events. Events are external factors responsible for state change Grouping Things Grouping things can be defined as a mechanism to group elements of a UML model together. There is only one grouping thing available − Package − Package is the only one grouping thing available for gathering structural and behavioral things. Annotational Things Annotational things can be defined as a mechanism to capture remarks, descriptions, and comments of UML model elements. Note – It is the only one Annotational thing available. A note is used to render comments, constraints, etc. of an UML element. Relationship Relationship is another most important building block of UML. It shows how the elements are associated with each other and this association describes the functionality of an application. There are four kinds of relationships available. Dependency Dependency is a relationship between two things in which change in one element also affects the other. Association Association is basically a set of links that connects the elements of a UML model. It also describes how many objects are taking part in that relationship. Generalization Generalization can be defined as a relationship which connects a specialized element with a generalized element. It basically describes the inheritance relationship in the world of objects. Realization Realization can be defined as a relationship in which two elements are connected. One element describes some responsibility, which is not implemented and the other one implements them. This relationship exists in case of interfaces. UML Diagrams UML diagrams are the ultimate output of the entire discussion. All the elements, relationships are used to make a complete UML diagram and the diagram represents a system. The visual effect of the UML diagram is the most important part of the entire process. All the other elements are used to make it complete. UML includes the following nine diagrams, the details of which are described in the subsequent chapters. Class diagram Object diagram Use case diagram Sequence diagram Collaboration diagram Activity diagram Statechart diagram Deployment diagram Component diagram Print Page Previous Next Advertisements ”;

UML – Basic Notations ”; Previous Next UML is popular for its diagrammatic notations. We all know that UML is for visualizing, specifying, constructing and documenting the components of software and non-software systems. Hence, visualization is the most important part which needs to be understood and remembered. UML notations are the most important elements in modeling. Efficient and appropriate use of notations is very important for making a complete and meaningful model. The model is useless, unless its purpose is depicted properly. Hence, learning notations should be emphasized from the very beginning. Different notations are available for things and relationships. UML diagrams are made using the notations of things and relationships. Extensibility is another important feature which makes UML more powerful and flexible. The chapter describes basic UML notations in detail. This is just an extension to the UML building block section discussed in Chapter Two. Structural Things Graphical notations used in structural things are most widely used in UML. These are considered as the nouns of UML models. Following are the list of structural things. Classes Object Interface Collaboration Use case Active classes Components Nodes Class Notation UML class is represented by the following figure. The diagram is divided into four parts. The top section is used to name the class. The second one is used to show the attributes of the class. The third section is used to describe the operations performed by the class. The fourth section is optional to show any additional components. Classes are used to represent objects. Objects can be anything having properties and responsibility. Object Notation The object is represented in the same way as the class. The only difference is the name which is underlined as shown in the following figure. As the object is an actual implementation of a class, which is known as the instance of a class. Hence, it has the same usage as the class. Interface Notation Interface is represented by a circle as shown in the following figure. It has a name which is generally written below the circle. Interface is used to describe the functionality without implementation. Interface is just like a template where you define different functions, not the implementation. When a class implements the interface, it also implements the functionality as per requirement. Collaboration Notation Collaboration is represented by a dotted eclipse as shown in the following figure. It has a name written inside the eclipse. Collaboration represents responsibilities. Generally, responsibilities are in a group. Use Case Notation Use case is represented as an eclipse with a name inside it. It may contain additional responsibilities. Use case is used to capture high level functionalities of a system. Actor Notation An actor can be defined as some internal or external entity that interacts with the system. An actor is used in a use case diagram to describe the internal or external entities. Initial State Notation Initial state is defined to show the start of a process. This notation is used in almost all diagrams. The usage of Initial State Notation is to show the starting point of a process. Final State Notation Final state is used to show the end of a process. This notation is also used in almost all diagrams to describe the end. The usage of Final State Notation is to show the termination point of a process. Active Class Notation Active class looks similar to a class with a solid border. Active class is generally used to describe the concurrent behavior of a system. Active class is used to represent the concurrency in a system. Component Notation A component in UML is shown in the following figure with a name inside. Additional elements can be added wherever required. Component is used to represent any part of a system for which UML diagrams are made. Node Notation A node in UML is represented by a square box as shown in the following figure with a name. A node represents the physical component of the system. Node is used to represent the physical part of a system such as the server, network, etc. Behavioral Things Dynamic parts are one of the most important elements in UML. UML has a set of powerful features to represent the dynamic part of software and non-software systems. These features include interactions and state machines. Interactions can be of two types − Sequential (Represented by sequence diagram) Collaborative (Represented by collaboration diagram) Interaction Notation Interaction is basically a message exchange between two UML components. The following diagram represents different notations used in an interaction. Interaction is used to represent the communication among the components of a system. State Machine Notation State machine describes the different states of a component in its life cycle. The notations are described in the following diagram. State machine is used to describe different states of a system component. The state can be active, idle, or any other depending upon the situation. Grouping Things Organizing the UML models is one of the most important aspects of the design. In UML, there is only one element available for grouping and that is package. Package Notation Package notation is shown in the following figure and is used to wrap the components of a system. Annotational Things In any diagram, explanation of different elements and their functionalities are very important. Hence, UML has notes notation to support this requirement. Note Notation This notation is shown in the following figure. These notations are used to provide necessary information of a system. Relationships A model is not complete unless the relationships between elements are described properly. The Relationship gives a proper meaning to a UML model. Following are the different types of relationships available in UML. Dependency Association Generalization Extensibility Dependency Notation Dependency is an important aspect in UML elements. It describes the dependent elements and the direction of dependency. Dependency is represented by a dotted arrow as shown in the following figure. The arrow head represents the independent element and the other end represents

UML Tutorial PDF Version Quick Guide Resources Job Search Discussion UML (Unified Modeling Language) is a standard language for specifying, visualizing, constructing, and documenting the artifacts of software systems. UML was created by the Object Management Group (OMG) and UML 1.0 specification draft was proposed to the OMG in January 1997. It was initially started to capture the behavior of complex software and non-software system and now it has become an OMG standard. This tutorial gives a complete understanding on UML. Audience This tutorial has been prepared for beginners to help them understand the fundamentals of UML. After completing this tutorial you will find yourself at a moderate level of expertise from where you can take yourself to the next levels. Prerequisites No specific skill is required as a prerequisite to understand the learning material in this tutorial. The reader must be enthusiastic to acquire knowledge on UML. Print Page Previous Next Advertisements ”;

UML – Modeling Types ”; Previous Next It is very important to distinguish between the UML model. Different diagrams are used for different types of UML modeling. There are three important types of UML modeling. Structural Modeling Structural modeling captures the static features of a system. They consist of the following − Classes diagrams Objects diagrams Deployment diagrams Package diagrams Composite structure diagram Component diagram Structural model represents the framework for the system and this framework is the place where all other components exist. Hence, the class diagram, component diagram and deployment diagrams are part of structural modeling. They all represent the elements and the mechanism to assemble them. The structural model never describes the dynamic behavior of the system. Class diagram is the most widely used structural diagram. Behavioral Modeling Behavioral model describes the interaction in the system. It represents the interaction among the structural diagrams. Behavioral modeling shows the dynamic nature of the system. They consist of the following − Activity diagrams Interaction diagrams Use case diagrams All the above show the dynamic sequence of flow in a system. Architectural Modeling Architectural model represents the overall framework of the system. It contains both structural and behavioral elements of the system. Architectural model can be defined as the blueprint of the entire system. Package diagram comes under architectural modeling. Print Page Previous Next Advertisements ”;

UML – Useful Resources ”; Previous Next The following resources contain additional information on UML. Please use them to get more in-depth knowledge on this topic. Useful Video Courses UML Online Training Course 78 Lectures 6.5 hours Tutorialspoint More Detail UML Class Diagrams 38 Lectures 2 hours Felix Tuna More Detail Object Oriented PHP & TDD with PHPUnit Course from Scratch 68 Lectures 12 hours Ogbemudia Terry Osayawe More Detail Complete guide to program a Video game with C++ since scratch Featured 25 Lectures 4.5 hours Oscar Daniel De La Cruz Jara More Detail Object-Oriented Analysis, Design and Programming with UML 122 Lectures 10 hours Packt Publishing More Detail Software Architecture with UML Modeling 19 Lectures 1.5 hours Nico @softcademy More Detail Print Page Previous Next Advertisements ”;