Shulou(Shulou.com)06/02 Report--

This article mainly shows you "what is the meaning of UML object graph", the content is easy to understand, clear, hope to help you solve your doubts, the following let the editor lead you to study and learn "what is the meaning of UML object graph" this article.

UML object graph

I. Overview

UML object graph (ObjectDiagram) describes the state of each object participating in the interaction at a certain time in the process of interaction. A UML object diagram can be seen as an instance of a class diagram at some point in time.

In UML, UML object diagrams use the same symbols and relationships as class diagrams, because objects are instances of classes. The following figure shows the model of the UML object graph. The node can be an object or a class, and the connection represents the relationship between the objects:

2. The difference between class diagram and UML object diagram.

The UML object graph class has three columns: name, attribute and Operand only two columns: name and attribute in the name column of the class, only the name of the class name object is in the form of "object name: class name", and the name of the anonymous object is ": class name". The attribute column of the class defines the feature object of all attributes and only defines the current value of the attribute. For use in test cases or examples, operations are not included in the UML object diagram because for objects that belong to the same class, the operation is the same class using association joins, which are defined by features such as names, roles, multiplicity, and constraints. Classes represent the classification of objects, so you must specify the number of objects that can participate in the association. Objects use chained links, chains have names, roles, but no multiplicity. Objects represent individual entities, and all chains are one-to-one, so multiplicity is not involved.

Modeling Technology of UML object Graph

I. object structure modeling

When modeling the design view of a system, a set of class diagrams can be used to fully describe the abstract semantics and the relationship between them. However, the object structure of the system can not be completely described by using UML object graph. For an individual class, there may be multiple instances, and for a set of classes that are related to each other, there may be quite a number of configurations available between objects. Therefore, when using a UML object graph, you can only display a set of concrete or prototype objects of interest in a certain sense. This is the modeling of the object structure, that is, a UML object graph shows a set of objects that are related to each other at some time.

To model the object structure, follow the following strategies:

(1) identify the modeling mechanism to be used. This mechanism describes the functions and behaviors of some of the systems being modeled, which are generated by the interaction of classes, interfaces, and other elements.

(2) for various mechanisms, identify the classes, interfaces and other elements involved in collaboration, as well as the relationship between these things.

(3) consider the script that runs through this mechanism. Freeze the script at a certain point and report on each object involved in the mechanism.

(4) display the status and attribute values of each object as needed to understand the script.

(5) the chain between objects is displayed to describe the instance of the association between objects.

II. Forward engineering and reverse engineering

1. Forward engineering

The forward engineering of UML object graph engineering is feasible in theory, but it is limited in practice.

2. Reverse engineering

It is very difficult to reverse engineer UML object graph. When debugging a system, it always depends on developers or tools.

The above is all the content of this article "what is the meaning of UML object Graph?" Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.