Intro to Eclipse Rick Mercer

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Intro to EclipseRick Mercer
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Outline
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Eclipse

• Eclipse is a universal tool platform
• An open extensible IDE for anything and nothing
  in particular
• Small runtime kernel
• Tools are added as plug-ins, many are free
• Tomcat, XML Editor, Java, C, C, UML
• J2EE development? GUI builder? UML modeling?
• Have to pay
• Has a workspace for managing resources
• Workspace is organized into projects

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Eclipse

• Open source project--can get it for free
• Version 1.0 Nov 01
• Version 2.1 March 03
• Version 3.0 July 2004
• Has its own compiler (but still need a JRE)
• IBM had 40 million invested before making it
  open source as Eclipse.org
• IBM, Rational, Borland, TogetherSoft, Fujitsu,
  Oracle, Sybase, Red Hat, Webgain, HP
• Board determines the goals and objectives

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Three Projects at Eclipse.org

• The Eclipse Platform (Eclipse)
• workbench into which tools can be plugged
• Subprojects Compare, Help, Search
• Java Development Kit (JDT)
• Led by Eric Gamma
• Subprojects Debug support for Java, UI
• Plug-in Development Environment (PDE)

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Open Source

• Eclipse is distributed under the Common Public
  License (CPL)
• It joins the likes of Linux, Apache and Mozilla

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JDT

• The Eclipse platform provides a way to integrate
  new tools
• Plug-in metaphor add new tools easily
• To be useful, Eclipse needs plug-ins
• When you download it, you will get the Java
  Development Toolkit (JDT)
• Run and debug Java Applets, Applications and
  JUnit Tests

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Perspectives

• Eclipse has many perspectives
• Each has several windows in a certain layout
• Different things happen on right clicks with
  different perspectives
• You will see, use, and switch between
• Java Perspective
• Debug Perspective

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Getting Eclipse on Your Machine

• If necessary, install recent version of Java
  (1.4.2)
• You only need the Java Runtime Environment (JRE)
• Get Eclipse release 3.0 (July-04)
• Unzip to a folder in Windows, use C\Program
  Files
• Does not infect registry or environment variables
• Create shortcut an put it on your desktop.
• Start Eclipse and enter a folder where you would
  like to store your projects (can change this
  later)
• Eclipse creates a folder named workspace under it
• Each new workspace folder looks like

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Click here to write code
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• This is the resource perspective with these views
• Navigator
• Outline
• Tasks
• Resources

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And then do these steps

• File gt New gt Project gt Java Project
• Enter Hello as the project name
• File gt New gt Class
• Enter First as the class name
• Click the box to get the main method stub
• Add System.out.println("Hello World")
• Run gt Run as gt Java Application
• Click on the Console tab
• Then Eclipse will look like the following

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Projects and Folders

• Projects are mapped to a folder under the
  workspace folder
• And packages are in subfolders under the project
  folder
• You will use a self-contained, high-level,
  platform-neutral hierarchy

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Perspectives, Views, Editors

• View A single pane in a perspective
• Perspective A collection of views
• Many plugins have their own perspectives
• Editors Different type for different files
• Could have a text editor or the Java editor
  (color syntax highlighting, auto-formatting, code
  completion), or PowerPoint,

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Why Eclipse?

• Integrated testing framework
• Optional Code completion
• Suggestions to fix errors (shows at error)
• Built in Java help
• Ability to add plug-ins
• Refactorings change signature, rename, extract
  method
• Code templates
• sop System.out.println("_")
• for for (int index 0 index lt n index)
• Faster compilation
• Nice debugger

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Debugging

• First need to set at least one breakpoint
• Use Debug as rather than Run as
• Use Step Filtering with Shift F5
• Later you will add filters to avoid stepping into
  Java classes
• Saves lots of time, no need to debug java

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Preferences

• Many things can be changed
• Fonts, code formatting, tabs at top or bottom of
  views, code generated for new files
• Can set debugging preferences and the above by
  importing a preference file
• Will specify coding style, comments, spacing,
  indentation,
• A team can use the same preference file to
  enforce coding style

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Testing Framework

• JUnit is a testing framework that is integrated
  into Eclipse
• Use this to test one method at a time
• Tests will always be available to detect when
  something breaks
• Used by professional developers to design and
  implement good code
• Has become a programming methodology called test
  driven development (TDD)

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Test Driven Development

• The steps
• Write a test that specifies a tiny bit of
  functionality
• Ensure the test fails (functionality not built
  yet!)
• Write only the code necessary to make the test
  pass
• Refactor the code, ensuring that it has the
  simplest design possible for the functionality
  built to date
• Important to use a testing framework like NUnit
• Improve internal structure of code without
  making externally visible changes to the
  functionality

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JUnit Preview

• JUnit http//www.junit.org/ is an open source
  testing framework to support TDD
• You write a separate unit test as a class
• In the same language as the production code
• Useful methods in class Assert include
• assertEqual, assertTrue, assertFalse,
  assertNotNull, assertNull

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Demo TDD with Java in Eclipse

• Develop a class that models an account at a bank
  that will be used in our Bank case study

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Write a test first that will not compile
Demo TDD with Java in Eclipse

• using NUnit.Framework
• public class BankAccountTest extends junit.frame
  ???
• public void testGetters()
• BankAccount b1
• b1 new BankAccount("Kim", 100.00)
• // Expected, Actual
• Assert.AreEqual("Kim", b1.ID)
• // Expected, Actual
• Assert.AreEqual(100.00, b1.Balance)

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Make test code compileLet test fail

• public class BankAccount
• public BankAccount(string ID,
• double initBalance)
• public string ID
• get return ""
• public double Balance
• get return 0.0
• // end class BankAccount

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Make Tests Pass

• public class BankAccount
• private string id
• private double balance
• public BankAccount(string ID, double
  initBalance)
• id ID
• balance initBalance
• public string ID
• get return id
• public double Balance
• get return balance

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Begin demo with a passing Properties test method

• Reinforces that objects have their own state (set
  of values) and they can remember their values

Now allow withdrawals next slide
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Withdraw

• Add behavior to allow withdrawals when the
  balance is large enough
• Don't allow withdrawals if the amount requested
  exceeds the account balance
• Continue with the following test list
• Withdraw when there is enough money
• Withdraw the whole balance
• Withdraw when there is not enough money
• Switch to VS.NET

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Why a Testing Framework?

• There is power in the green bar
• Students verify their code works without
• Intro students can use testing frameworks

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Why use TDD in CS1?

• Helps distinguish objects and classes
• Provides a process
• students develop one method at a time
• Better than one class at a time
• Hypothesize and verify
• Set up an experiment, written as a test
• Verify it works (or that it doesn't)
• Makes for better projects and test questions
• Allow loans to max of 2,000 in increments of 100

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Benefits of TDD

• Benefits
• Fewer defects
• Less debugging
• More confidence
• Better design
• Catches errors immediately

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• Is testing important?

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Structured Labs

• A set of structured labs designed for CS1 in C
  will be available from the course web site
• http//www.cs.arizona.edu/classes/cs186/sum
  mer04/
• Plan to add to
• http//www.msdnaa.net/curriculum/repository.asp
  x
• Reinforce concepts with hands on activities, in a
  closed lab setting or as homework
• Rick Mercer mercer_at_cs.arizona.edu

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• using NUnit.Framework
• TestFixture
• public class BankAccountTest
• Test
• public void Properties()
• BankAccount b1
• b1 new BankAccount("Kim", 100.00)
• Assert.AreEqual("Kim", b1.ID)
• Assert.AreEqual(100.00, b1.Balance)
• Test
• public void WithdrawWithEnoughMoney()
• BankAccount b1
• b1 new BankAccount("Kim", 100.00)

BankAccountTest.cs
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• public class BankAccount
• private string id
• private double balance
• public BankAccount(string ID, double
  initBalance)
• id ID
• balance initBalance
• public string ID
• get return id
• public double Balance
• get return balance

BankAccount.cs
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Other Cool Things

• Can ensure a method is throwing an exception
• This test will succeed
• Test
• ExpectedException(typeof(InvalidOperationExceptio
  n))
• public void Pop()
• Stack s new Stack()
• s.Pop()
• If s.Pop() is removed, the test would fail

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Other Cool Things

• Occasionally you need the debugger
• To use the Debugger with NUnit
• Set a breakpoint on the failed assertion
• Proceed as before (run with NUnit)
• Execution stops at the breakpoint
• Step through the source code, watch variables

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Summary

• Eclipse is a workbench to which tools such as JDT
  can be added
• Has perspectives, views, and editors
• Editor in use depends on the resource
• Has preferences that can be changed
• Lots of help for software developers
• Complex Takes a while to get used to it
• But the tools are helpful, you'll save time and
  wrote better code