#4 UML Diagrams

#4 UML Diagrams - Activity diagrams help users to describe...

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Activity diagrams help users to describe visually the sequence of actions that leads you through the completion of a task. Activity diagrams are a useful analysis tool and can be used for process reengineering, i.e., redesigning process. In this way, activity diagrams are a progressive
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An activity diagram is pretty close to a flowchart. The symbols are similar but not the same. Activity diagrams are good at helping you to capture, visualize, and describe an ordered set of actions from a beginning to an end. Activity diagrams are created as a finite set of serial actions or a combination of serial and parallel actions.
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An activity diagram is pretty close to a flowchart. The symbols are similar but not the same. Activity diagrams are good for capturing details
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Initial Node Every activity diagram has one initial node symbol. This is a solid circle. Control Flow A control flow is a directed arrow. A control flow is also referred to as just a flow or an edge. A common way to adorn a control flow is to add a guard condition. A guard condition acts as a sentinel that requires a test be passed before flow continues. In code, commonly this would be implemented as an if- conditional test.
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Different Ways of Showing Flows Using Connector Nodes Using Objects
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Different Ways of Showing Flows Using Pins - analogous to parameters in implementation. The name or value of a pin leaving one action should be thought of as an input parameter to the next action. Actions Action nodes are the things that you do or that happen in an activity diagram
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Actions Two of the most important aspects of actions are the order in which they occur and the name you give them. Actions are permitted to have one or more incoming flows and only one outgoing flow. If there is more then one incoming flow, then the action will not transition until all incoming flows have reached that action. Actions can split into alternate paths using the decision node or transition into parallel flows using the fork node but only a single flow actually should be attached as an outgoing flow for an action.
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Adding Preconditions and Postconditions Preconditions and postconditions can be added to a model using a note—the stereotype symbols with the word precondition or the word postcondition in between and the name of the condition. The note is attached to the action to which the condition or conditions applies. This is referred to as design by contract and often is implemented in code as an assertion combined with a conditional test.
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Decision and merge nodes were called decision diamonds in flowcharts. Decision and merge nodes use the same symbol and convey conditional branching and merging. Transition Forks and Joins
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#4 UML Diagrams - Activity diagrams help users to describe...

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