The state diagram is basically a Harel statechart that uses a standard notation. It can be used to describe a number of things, and this includes business processes as well as computer applications.

There are a number of notational elements which make up this diagram, and these are the filled circle, the hollow circle, the rounded rectangle, the arrow, and the thick horizontal line. The filled circle may be used to point to the initial state. The hollow circle may contain a smaller circle which is filled, and this will indicate the final state is there is any. The rounded rectangle will be used to define a state. The top of this rectangle will have the name of this state, and it may have a horizontal line in its center.

Below the horizontal line at the center, activities which are done in the state may be listed. The arrow will be used to represent a transition. The name of an event may be listed, and a guard expression may also be used. If the guard expression is used, it will be enclosed within brackets. When this is done, it means that the expression will be true if the transition is to occur. If any action is carried out during this transition, it may be labeled with the "/" symbol. A thick horizontal line with a "1" or "x>1" lines will be used to represent either a join or a fork.

Another concept that you may frequently encounter in UML are extensions. One thing that many developers do is allow the arcs to flow from a certain number of states to another group of states. This will only be useful in situations where the system is allowed to be in various states simultaneously, and this implies that the individual states will only define a condition or another part of the global state.

This formulation is known as the Petri net. There are additional extensions which will allow you to integrate your flowcharts inside the Harel state charts. When you use this extension, you can develop software that is driven by both events and workflow.

Diagrams are an important part of the Unified Modeling Language, and they have been fully utilized by the many developers who use this language. The introduction of Harel statecharts has made things easier, and now elements are allowed to exist in multiple states at the same time.

This combination is expected to increase the efficiency of UML, and this will allow it to be more powerful for developers who wish to design high end applications. If you're working remotely, and you need a powerful language that is robust and flexible, UML is something that you will want to take a look at.

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