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Each party in an interaction is represented by a target. In other words, a target is something that can be communicated with during an interaction.
Each target is of a certain kind which determines what it represents and how it looks. Trace Modeler supports the following kinds :
If you're not modeling software objects, you'll only need the three kinds of objects and have little use for classes.
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This target represents a plain object. This is the most common kind of target, use it when you have no reason to use any of the others kinds. |
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A multiobject represents a collection of objects. Use it if you want to show an interaction with certain elements of a collection without distinguishing between individual elements. Note that messages sent to a multiobject are received by the elements, not by the collection object itself. |
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An active object is an object that can initiate an interaction, i.e. it can start a new flow of control. Use it for autonomous entities such as actors, agents, applications, OS-processes, threads, etc. when you want to stress or use their ability to start an interaction. Note that detailing multiple flows of control on a single diagram can be difficult. |
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This target represents a class. Use it if an interaction requires a class message. Simply provide a target for the corresponding class and send the message to it. If you're modeling software objects in some object-oriented programming language, class messages correspond to calls to static/shared methods. |
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An active class is a class that can initiate an interaction, i.e. it can start a flow of control. Use this when... Well, let me know if you find a good use for such a target ;o) |
Some often used object stereotypes can be represented by icons :
You can change the size of these icons with the 'Target icon size' property of a diagram style.
If you want to use a stereotype for which no icon is available (or prefer not to use icons), simply add the stereotype on a separate line at the top of the target label.
Each target has a label that describes it and can span multiple lines. It usually consists of a single line, but if you need to add a stereotype or save some horizontal space you'll want to use multiple lines of text.
Trace Modeler will automatically determine the correct length of each target's lifeline.
The order in which targets are shown on the diagram not only affects how your diagram looks, but also how easy it is to understand it.
The target order combined with the diagram style properties 'Lifeline spacing' and 'Layout direction' determines the horizontal location of each target.
Reordering targets is easy with Trace Modeler : simply rearrange them on the diagram and everything else will be adjusted accordingly.
You can reorder the targets by changing the relative positions of individual targets or let Trace Modeler optimize the order based on some heuristics.
The destruction of a target is shown on the diagram by placing a cross on its lifeline and ending the lifeline at that point in time.
Trace Modeler gives you three different ways to effect its demise by setting its destruction property to one of the following :
The following UML sequence diagram shows how the different settings influence if and where the cross is placed on the lifelines :
