Systems Analysis II Package and Deployment Diagrams

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Systems Analysis IIPackage and Deployment
Diagrams

• INFO 355
• Glenn Booker

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Packages

• Classes are the most basic logical element in an
  OO system
• We need a way to group related classes into
  larger structures
• A Package can contain classes, other packages, or
  a combination of the two

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Packages

• Packages can therefore have a large scope (e.g.
  entire subsystems)
• In writing, a double colon separates a package
  name from its contents
• Packageotherpackageclassname

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Package Diagram

• The Package Diagram can be very helpful in
  understanding the architecture of a system
• What are the big pieces of this system?
• Defining connections among packages also helps
  encourage higher modularity for each package

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Packages

• In a diagram, a package may be just a tabbed
  folder
• Or a package can list its contents (classes
  and/or packages)

(this was done manually in Visio)
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Packages

• The smallest packages can be drawn large enough
  to include the class diagram they contain

(also done manually)
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Packages

• If showing a class diagram within a package, can
  show connection to other packages by using the
  fully qualified name of the class in another
  package
• See also the ltltsystemgtgt stereotype

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Package Diagram

• Packages can contain both packages and classes
• Dashed lines show direction of dependency

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Package Dependencies

• For additional refinement, dependencies can be
  labeled with various stereotypes, such as
• Call
• Instance
• Copy
• Derived
• Send
• Import

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Package Generalization

• Generalization can be shown with packages, not
  just classes
• Might be used in implementation to distinguish
  among different kinds of similar interfaces, for
  example

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Packages

• It is possible to have classes with identical
  names in different packages
• CustomerPerson
• ClientPerson
• You might want this to reuse non-primitive data
  type classes

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Package Stereotypes

• Packages can specify stereotypes to indicate
  their purpose
• ltltfaçadegtgt to indicate the façade pattern is
  being implemented with this package
• ltltsystemgtgt to indicate the package represents an
  external system

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Package Stereotypes

• ltltstubgtgt could represent a package which isnt
  going to be implemented yet, but is a placeholder
• ltltframeworkgtgt represents a commercial development
  framework

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Package Visibility

• Packages can have the same visibility
  characteristics as any class, method, or
  attribute
• Public
• Private
• Protected
• This doesnt show on its symbol

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Deployment Concept

• Keep the typical 3-tier architecture in mind,
  when trying to define the contents of packages
• The physical tiered structure of
• Web server / app server / data server
• Corresponds nicely to the MVC design pattern
• M(data) V(web) C(app)

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Deployment Concept

• Your system might be simpler, or more complex
  than 3-tier
• Large systems may have specialized servers for
  each type of application
• Data mining servers
• Intranet servers
• Security servers
• File servers, etc.

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Deployment Concept

• So your systems approach for collecting classes
  into packages, and where those packages become
  executable code, should be consistent
• Can define the scope of packages so they will
  each be implemented on a single type of server,
  e.g. may group classes into packages by MVC type

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Deployment Diagram

• The deployment diagram is the only UML diagram
  specifically for the PHYSICAL implementation of
  a system
• The deployment diagram shows nodes connected by
  communication paths

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Nodes

• A node is some physical environment which can run
  software
• A device is a piece of hardware which runs
  software
• An execution environment is software which hosts
  other software, such as an operating system
• Nodes contain the artifact files (exe, dll, jar,
  scripts, data, HTML)

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Nodes

• Nodes can simply list the artifacts within them,
  or show a simple diagram to indicate the
  connections between artifacts
• Additional properties can be added in brackets
  , though this isnt part of the UML standard
• vendoraa, OSbb, servercc

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Nodes

• Visio allows editing the name, and adding
  comments to a node
• Can resize the node, and superimpose the artifact
  names manually

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Communication Paths

• The communication path between nodes is a plain
  line with a label
• The label shows the protocol or type of messages
  sent over the path, a front slash /, then the
  type of network connection
• http/Internet, MILSTRIP/LAN
• Paths within a node dont need to show the type
  of connection
• Just the protocol JDBC, ODBC