Subtitles of the Movie

This movie talks about object diagrams and package diagrams both of which are related to class diagrams. This is an example of an object diagram, an object diagram illustrates the structure of the system at a particular moment in time. So that means that an object diagram is like a snapshot. And this makes it of course a static diagram. Object diagrams both check and refine class diagrams by showing instances of classes and their relationships in various configurations. So just as an object is an instance of a class, an object diagram can be thought of as an instance of a class diagram. And object diagrams look a lot like class diagrams they use much of the same notation. For example the association between these two objects here, object diagrams show instances of classes which can be anonymous, you see these two here are anonymous instances of a class. And they show the links to other objects. So we got objects shown in these rectangular boxes, you can include both the object name and the class name, just the name of the object or just the name of the class and the links between objects the associations of various kinds. As you see here with these straight lines you can show multiplicity and can also optionally label the association between objects. In this example object one contains object two and is also a parent for these two anonymous objects. So object diagrams helped to clarify the structure shown in a class diagram, their great at showing example configurations of objects. Let's move onto the package diagram, like object diagrams, package diagrams can be seen as a type of class diagram and package diagrams focus on packages and as you can see this is an example of a package, it looks like a tabbed folder with the name of the package labeling it. Sometimes you'll see the name of the package here, sometimes you'll see it up on the tab. Packages bundle other elements together into higher level elements, their like java packages or C plus plus namespaces. And package diagrams show how packages and that includes the elements they contain are organized giving you a higher level view of say class diagrams. These diagrams show packages as you see here and the various dependencies that exist among them. This dashed line with the open arrowhead represents a dependency and as you can see you can label or stereotype the dependencies to show different kinds of dependencies. Here we have merge and over here we have import. By the way packages are most commonly used to organize classes and also use cases. But a package can contain any UML element so even though you'll see them, use them most frequently to contain classes they do offer you a lot of flexibility in your UML diagrams.