Integrating ObjectOriented Metrics Analysis into the BlueJ Development Environment

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Integrating Object-Oriented Metrics Analysis into
the BlueJ Development Environment

• Jonathan Chapman

Computer Science Dept. Appalachian State
University Boone, NC
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Presentation Roadmap

• The BlueJ IDE
• Extending BlueJ
• Why/How it is done
• A sampling of extensions
• The Metrics Analysis Tool (MAT)
• Running the MAT from inside BlueJ
• AppLaunch extension
• Other uses of AppLaunch

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The BlueJ IDE

• Designed specifically for introductory teaching
  of object orientation with Java.
• Features
• graphical class structure display
• graphical and textual editing
• built-in editor, compiler, JVM, debugger, etc.
  
• easy-to-use interface, ideal for beginners
• interactive object creation, object calls,
  testing
• incremental application development

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BlueJ Screenshot
Interface
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Extending BlueJ

• Extension API allows 3rd parties to extend the
  core system with additional functionality.
• Extension sampler
• Submitter configurable submission of projects
• Checkstyle automated checking of style
  conventions
• Exporter exports BlueJ projects for use in other
  IDEs (e.g., NetBeans ant scripts)
• Remote File Manager integrated sftp with server

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BlueJ Extension API

• IDE Object Access
• Controlled access to users projects, packages,
  classes, methods, objects, fields
• Editor Control
• Open/close files, hide/show editor, get/set
  selection, read/modify text,
• Event Listening
• Application events initiation, package
  open/close
• Compilation events initiation, success, failure,
  completion
• Invocation events before/after, parameters,
  returns
• IDE menu presence
• Tools
• Preferences

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Making a BlueJ Extension

• Implementation
• main class extends Extension class
• Add tools/preferences menu items
• Attach listeners and handlers
• Deployment
• Create jar file of extension code
• Create Main-Class attribute in Manifest
• Install jar file into appropriate BlueJ folder
• BlueJ automatically sees valid extension jars

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Metrics Analysis Tool (MAT)

• Goals
• Simple, Student-Based Metrics
• Visual Presentation
• Easy to use
• Extendable (more metrics)
• Standalone, usable outside of BlueJ

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MAT Features

• 24 Statistics, 9 Ratios, 9 Warnings
• Graphs that change when statistics are selected
• Viewable Abstract Syntax Tree (AST)
• Can open multiple Java files simultaneously
• Extensible (custom Ratios, Stats, and Warnings).
• Prebuilt interface to AST for further use(some
  structures cached at parse-time for quicker
  access).

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MAT AST Viewer
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MAT Graph View
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MAT Example Analysis
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MAT in BlueJ

• How do we Incorporate Standalone with IDE?
• Why should user type in file information when
  this could be automated?

Introducing Application Launcher Extension...
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Application Launcher

• BlueJ extensions are coupled to BlueJ IDE
• What about useful applications that are not
  BlueJ extensions?
• Do we need two versions of applications that have
  homes inside and outside BlueJ ?
• MAT is such an application
• Wanted a way to connect it to BlueJ, but without
  making it limited to BlueJ
• AppLaunch is a BlueJ extension allowing BlueJ
  user to launch an application from within BlueJ

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AppLaunch Features

• Tree model of applications
• Applications can run at startup
• Applications can work on 0, 1, or multiple files
• Maintains window position and size at closing
• Always-on-Top Capability (relative to BlueJ)
• Adjustable panel dividers and window size
• Refreshes when packages are opened/closed
• Displays BlueJ projects in tree-form (optional)

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Application Tree Only
Project and Application
View
View
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AppLaunch Preferences
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AppLaunch Add/Edit
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AppLaunch Uses

• Launch Alternative Editors
• Transition to other environments
• Software Metrics Tools
• Student Habit Research
• Frequency of compilations, time logs, etc.
• Quick Links to Websites
• Course/Lab web site