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UML Diagrams
Zicomi Systems publishes some UML example diagrams online from the world famous UML dictionary.
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Version 2.5 Released
Zicomi Systems is delighted to announce that version 2.5 of Zicomi Mentor is released. With support for UML 2.0 and all thirteen UML diagrams
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Zicomi Systems' Director
speaks about the UML at Objects by Design - an informative interview
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Partner Programme
Zicom Systems is delighted to announce a new world wide partner programme, become a partner today.
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OMG Member
Zicom Systems is made a member of the OMG!
UML Element Description
Lifeline
Lifeline    
A lifeline represents the lifetime or existence of the participant located at the head of the dashed line. Regardless of whether a participant has an execution occurrence, if it has a lifeline then it has been created. Where the lifeline "disappears" beneath the execution occurrence it is assumed to continue to exist. If the participant is created or destroyed during the period of time represented by the diagram the lifeline will start or stop at the designated points.
Lifeline (Class Instance)
Lifeline (Class Instance)    
A lifeline represents the lifetime or existence of the participant located at the head of the dashed line. Regardless of whether a participant has an execution occurrence, if it has a lifeline then it has been created. Where the lifeline "disappears" beneath the execution occurrence it is assumed to continue to exist. If the participant is created or destroyed during the period of time represented by the diagram the lifeline will start or stop at the designated points.
Lifeline (Actor Instance)
Lifeline (Actor Instance)    
A lifeline represents the lifetime or existence of the participant named at the head of the dashed line. Regardless of whether a participant has an execution occurrence, if it has a lifeline then it has been created. The notation of the head of a lifeline changes depending on what type of element it represents. In this form the lifeline represents an actor instance or an actor playing a role with respect to the interaction.
Execution Occurrence
Execution Occurrence    
An execution occurrence (activation) represents a period in the participant 's lifetime when it is performing an action or waiting for another participant to complete an action and return. A lifeline can have a number of execution occurrences that and these will be positioned along the lifeline, obscuring the dashed line.
Synchronous Message
Synchronous Message    
A synchronous message is a message that pauses the flow of execution within the calling instance. The instance waits until the message is returned.
Asynchronous Message
Asynchronous Message    
An asynchronous message means that the caller dispatches the stimulus or message to the receiver and does not wait for a return but continues immediately with the next step in its own execution.
Reply Message
Reply Message    
A reply message denotes a return from a procedure call. This is an explicit representation of the return, which if it is not present, is implied in the synchronous message.
Message (Instance Creation)
Message (Instance Creation)    
An instance creation is used if an instance needs to be created during the lifetime represented by the diagram. Many of the instances are assumed to be in existence when the diagram lifetime starts, those that aren't need to be created. Created instances typically appear at a point on the diagram offset from the other instances. When time is represented by the vertical axis they appear lower than the other instances.
Stop
Stop    
A stop is used to denote that a participant is destroyed during the lifetime represented by the diagram. The lifeline is ended indicating that the participant no longer exists; the dashed line ends in a small cross positioned at the end of the lifeline. A participant may stop itself.
Comment (Note)
Comment (Note)    
A comment can contain textual information or graphical symbols that add additional information to a diagram or model. The information can take many forms from very formal, in the case of constraints, to conversational, in the case of working notes. Comments can be placed anywhere in a model or diagram, and simply by their proximity and alignment; they can be applicable to one or more elements. They may also be attached either to one or more elements by a comment attaching line.
Comment (Note) Attaching Line
Comment (Note) Attaching Line    
A comment attaching line is a dashed line that is used to attach a comment (note) to a model element in a diagram. The comment (note) attaching line is not a UML relationship and has no semantics beyond signifying that the contents of a comment apply to the model element it is attached to. A comment may be attached to any number of model elements or may exist in isolation and by placement in proximity to one or more model elements signify that it applies to those elements.
Alternatives (Combined Fragment)
Alternatives (Combined Fragment)    
An alternatives interaction operator (signified by the value of alt) defines a combined fragment where one or more behavior options or choices are expressed. One (and only one) of the alternatives (operands) can execute and only when the guard condition evaluates to TRUE.
Loop (Combined Fragment)
Loop (Combined Fragment)    
A loop interaction operator (signified by the value of loop) defines a combined fragment where the messages contained in the fragment are repeated a number of times. The guard contains a lower bound defining the minimum number of times the operand must loop, an upper bound defining the maximum number of times the operand will be executed and a boolean expression (evaluated after the operand has looped the minimum number of times) which if false will terminate the loop.
Option (Combined Fragment)
Option (Combined Fragment)    
An option interaction operator (signified by the value of opt) defines a combined fragment where there is a choice between a single defined set of traces occurring or no traces. It is semantically equivalent to an alternatives operator (alt) where there is a single choice between a set of traces and an empty alternative.
Negative (Combined Fragment)
Negative (Combined Fragment)    
A negative interaction operator (signified by the value of neg) defines a combined fragment where the enclosed traces are all invalid. The operator is used to express the fact that the traces cannot occur. By implication any traces not enclosed in the negative interaction operator are valid. A combined fragment with a negative operator can have one (and only one) operand.
Break (Combined Fragment)
Break (Combined Fragment)    
A break interaction operator (signified by the value of break) defines a combined fragment where the messages enclosed within the fragment are performed instead of the messages in the outer (enclosing) fragment. The break operator is typically used when a given message or set of messages will halt the performance of the enclosing set of messages.
Parallel (Combined Fragment)
Parallel (Combined Fragment)    
A parallel interaction operator (signified by the value of par) defines a combined fragment where the messages contained in the operands can be interleaved. It thus defines the set of traces that can occur at the same time or overlap with each other with respect to time.
Found Message
Found Message    
A found message is a kind of message where the receiver (event occurrence) is known but the sender (event occurrence) is not known. It is assumed that the sender exists but is outside the scope of the model.
Lost Message
Lost Message    
A lost message is a kind of message where the sender (event occurrence) is known but the receiver (event occurrence) is not known. It is assumed that the reason it does not have a receiver (reception) is because it never reached its destination.
Recursive Message
Recursive Message    
A recursion message is a message where an instance is both the caller and the receiver of the message.
State Invariant
State Invariant    
A state invariant is an interaction fragment that places a constraint on the state of the lifeline on which it is located. The lifeline represents a set of instances and the constraint applies to these instances. It is evaluated at runtime and if the state invariant evaluates to false the message is considered to be invalid.
Interaction Occurrence
Interaction Occurrence    
An interaction occurrence stands in the place of an interaction or portion of an interaction. An interaction occurrence is a diagrammatic device for reusing or copying the contents of an interaction to another diagram.
Gate
Gate    
A gate is a type of message end that represents the connection point between a message that exists within an interaction fragment and a message outside the interaction fragment. A gate is a formal mechanism for connecting messages ensuring that every message has a sender and a receiver. Gates can exist in a number of contexts: formal gates used in interactions, actual gates used in interaction occurrences and expression gates used in combined fragments.
Assert (Combined Fragment)
Assert (Combined Fragment)    
An assertion interaction operator (signified by the value of assert) defines a combined fragment where the messages contained in the fragment are the only valid messages that can occur in the context. If any other messages occur they are considered to be invalid.
Consider (Combined Fragment)
Consider (Combined Fragment)    
A consider interaction operator (signified by the value of consider) defines a combined fragment where the messages listed are to be considered within the fragment. The messages defined as part of the operator are drawn in the fragment.
Ignore (Combined Fragment)
Ignore (Combined Fragment)    
An ignore interaction operator (signified by the value of ignore) defines a combined fragment where the messages listed are to be ignored within the fragment. This means that these messages are insignificant in the context of the fragment and can be ignored.
Region (Combined Fragment)
Region (Combined Fragment)    
A critical region interaction operator (signified by the value of region) defines a combined fragment where the messages contained in the operand cannot be interleaved with other messages from other lifelines enclosed in the region. It expresses that a set of traces are to be treated atomically and cannot be interrupted or affected by other traces.
Strict Sequencing (Combined Fragment)
Strict Sequencing (Combined Fragment)    
A strict sequencing interaction operator (signified by the value of strict) defines a combined fragment where the sequence of the event occurrences must occur in the order they are defined regardless of which lifeline is involved.
Weak Sequencing (Combined Fragment)
Weak Sequencing (Combined Fragment)    
A weak sequencing interaction operator (signified by the value of seq) defines a combined fragment where the order of event occurrences within one operand are significant and event occurrences on different lifelines can be interleaved, but event occurrences on the same lifeline, in different operands must occur in the order of the operands. Thus event occurrences in the first operand must occur before event occurrences in the second operand if they are on the same lifeline.
Continuation
Continuation    
A continuation is an interaction fragment that is used with alternative and weak sequencing combined fragments. It is a device that expresses the continuation of the different branches of the enclosing combined fragment.
General Ordering
General Ordering    
A general ordering is a named element that relates two event occurrences (message ends) specifying that the event occurrence at the tail end must occur before the event occurrence at the arrowhead end of the message.
Object
Object    
An object represents a distinct instance of a class. It has unique identity as well as attribute values, which determine its state at any point in time. An object can exhibit behavior, but only as a result of being an instance of a class. An object is an instance of one and only one class.
Unified Modeling Language and UML are either registered

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