An object is an instance of a class. In the UML metamodel
Object
is a sub-class of
Instance
. Within a sequence diagram objects may be
used to represent a specific instance of a class. Unlike collaboration
diagrams (see Chapter 20, Collaboration Diagram Artifact Reference), sequence diagrams
cannot show generic behavior between classifier roles.
An object is represented on a sequence diagram in ArgoUML as a plain box labeled with the object name (if any) and class name, separated by a colon (:). As links with stimuli to and from other objects are added, a time line grows down from the object. This is thin where the object does not have control and thick where it does.
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The current release of ArgoUML shows interactions between objects, although the UML standard for sequence diagrams is for interaction between instances of any classifier). However the actual implementation in ArgoUML permits any classifier to be used with the object, and so the diagram can successfully represent instances of actors for example as well as classes. |
The details tabs that are active for objects are as follows.
ToDoItem
Standard tab.
Properties
See Section 18.2.2, “Object Property Toolbar” and Section 18.2.3, “Property Fields For Object” below.
Documentation
Standard tab.
Style
Standard tab. The values for the bounds of the object notionally define the bounding box of the object and its time line. However if you change them it will have no effect, and the original values will be reset when you next revisit the tab.
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In the current release of ArgoUML changing the values of this field is possible, but will make a (temporary) mess of the screen display. Selecting the object on the screen causes the original values to be restored and the screen refreshed. |
Source
Standard tab, but with no contents.
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An object should not generate any code, so having this tab active is probably a mistake. |
Constraints
Standard tab. ArgoUML only supports constraints on Classes and Features (Attributes, Operations, Receptions, and Methods), so this tab is grayed out.
Tagged Values
Standard tab. In the UML metamodel,
Object
has the following standard
tagged values defined.
persistence
(from the
superclass, Instance
. Showing the
permanence of the state information associated with the
object. Values transitory
(state is
destroyed when the object is destroyed) and
persistent
(state is preserved when the
object is destroyed).
derived
(from the
superclass, ModelElement
). Values
true
, meaning the object is
redundant—it can be formally derived from other
elements, or false
meaning it
cannot.
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Derived objects still have their value in analysis and design to introduce useful names or concepts, and in design to avoid re-computation. |
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The UML |
Go
up
Navigate up through the package structure.
Delete
This deletes the object from the model
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This is a deletion from the model
not just the diagram. To delete an
object from the diagram, but keep it within the model, use
the main menu |
Name
Text box. The name of the object. By convention object names start with a lower case letter and use bumpy caps to divide words within the name.
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ArgoUML does not enforce this naming convention. |
Classifier
Drop down selector. The name of the classifier of which this is an object.
![]() | Caution |
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In the current release of ArgoUML the drop down selector will include all classifiers (i.e. interfaces, actors, use cases and datatypes as well), which is what is wanted on the diagram, although it should properly be called an instance, rather than an object. In practice only instances of classes and actors make much sense. |
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In the current release of ArgoUML the same graphical presentation is used, even if the object is actually representing an instance of an actor (when a stick-man would be more usual). |
Stereotype
Drop down selector. Object has no stereotypes by
default in the UML standard, but ArgoUML provides the
stereotypes, machine
,
organization
and
person
.
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ArgoUML also provides the stereotype
|
Navigate Stereotype
icon. If a
stereotype has been selected, this will navigate to the
stereotype property panel (see Section 17.4, “Stereotype”).
Namespace
Text box. Records the namespace for the object. This is the package hierarchy.
Button 1 click on the entry will navigate to the package defining this namespace (or the model for the top level namespace).
Stimuli Sent
Text area. Lists the stimuli sent to this object.
Button 1 click navigates to the selected entry, button 2 gives a pop up menu with five entries.
Open
. Navigate to the
selected stimulus.
Add
. Add a new
stimulus.
![]() | Caution |
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In the current release of ArgoUML this entry is always grayed out. Stimuli can only be added from the diagram. |
Delete
. Delete the selected
stimulus.
![]() | Caution |
---|---|
In the current release of ArgoUML this entry is always grayed out. Stimuli can only be deleted from the diagram. |
Move Up
. Only available where
there are two or more stimuli, and the stimulus selected is not
at the top. It is moved up one.
![]() | Caution |
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In the current release of ArgoUML this entry is always grayed out. Stimuli can not be moved in the order. To change the order a stimulus must be deleted and then recreated on the diagram. |
Move Down
. Only available where
there are two or more stimuli listed, and the stimulus selected
is not at the bottom. It is moved down one.
![]() | Caution |
---|---|
In the current release of ArgoUML this entry is always grayed out. Stimuli can not be moved in the order. To change the order a stimulus must be deleted and then recreated on the diagram. |
Stimuli Received
Text area. Lists the stimuli received by this object.
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In the current release of ArgoUML this field is completely broken. No entries are every shown. |
Button 1 click navigates to the selected entry, button 2 gives a pop up menu with five entries.
Open
. Navigate to the
selected stimulus.
Add
. Add a new
stimulus.
![]() | Caution |
---|---|
In the current release of ArgoUML this entry is always grayed out. Stimuli can only be added from the diagram. |
Delete
. Delete the selected
stimulus.
![]() | Caution |
---|---|
In the current release of ArgoUML this entry is always grayed out. Stimuli can only be deleted from the diagram. |
Move Up
. Only available where
there are two or more stimuli, and the stimulus selected is not
at the top. It is moved up one.
![]() | Caution |
---|---|
In the current release of ArgoUML this entry is always grayed out. Stimuli can not be moved in the order. To change the order a stimulus must be deleted and then recreated on the diagram. |
Move Down
. Only available where
there are two or more stimuli listed, and the stimulus selected
is not at the bottom. It is moved down one.
![]() | Caution |
---|---|
In the current release of ArgoUML this entry is always grayed out. Stimuli can not be moved in the order. To change the order a stimulus must be deleted and then recreated on the diagram. |