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The Java Development Tools project

The Java Development Tools project. What we'll cover here. The JDT environment Creating and running a program Automating testing with JUnit Using Ant and javadoc. The JDT environment. The Java Development Tools. A set of tools for writing, compiling, testing, and debugging Java code.

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The Java Development Tools project

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  1. The Java Development Tools project

  2. What we'll cover here • The JDT environment • Creating and running a program • Automating testing with JUnit • Using Ant and javadoc

  3. The JDT environment

  4. The Java Development Tools • A set of tools for writing, compiling, testing, and debugging Java code. • Note: Compiling happens automatically whenever you save your code. It's not a separate step. • The Eclipse SDK includes the Java tools. See eclipse.org/jdt if you want to learn more about the project.

  5. JDT perspectives • The most useful perspectives for Java development are Java and Debug. • There are also the Java Browsing and Java Type Hierarchy perspectives. • We'll look at the Java perspective now; we'll cover the Eclipse Debugger later.

  6. The Java perspective Class outline Syntax-aware Java editor Class hierarchy

  7. The Java editor • As you'd expect from a world-class IDE, Eclipse has a color-coded Java editor. • As you type, it automatically highlights the Java syntax and indents your code. • If there are errors, they're indicated when you save the file (if not before).

  8. The Java editor

  9. Code assist • If you type Ctrl+Space, Eclipse shows you the relevant method signatures and the javadoc for each. • This works for code you write as well as the standard Java libraries. • You don't have to run javadoc against your code for this to work. The documentation above comes from the comment in the source code.

  10. Globalization • Eclipse has an "Externalize Strings" function that helps you manage translation or localization of your projects.

  11. Other great features • Generate getters and setters automatically • "Quick Fix" certain problems • Automatically organize import statements • Add imports as necessary, remove unused imports, specify which imports are used • Refactoring code • Rename classes, methods, fields • Create an interface from a class • Move classes, methods, fields

  12. Creating and running a program

  13. Creating and running code • It's a short process: • Create a Java project • Create a Java package • Create a Java class in that package • Set up a run configuration • Run your code This can be confusing to newcomers; compiling and building is not a separate step.

  14. Creating a Java project • Start with FileNew Project… • Choose Java Project, give it a name and click Finish.

  15. Creating a Java Project • If you click Next after you give your project a name, you'll see other options. You can use these to set the classpath of your project, among other things.

  16. Creating a Java package • To create a Java package, right-click on your new project in the Package Explorer, then choose NewPackage…

  17. Creating a Java package • Enter a name for your package. • If you break Java style rules (maybe your package begins with an uppercase letter), Eclipse reminds you.

  18. Creating a Java package • Your new package appears in the Package Explorer beneath your project.

  19. Creating a Java class • To create a Java class, right-click on your new package in the Package Explorer, then choose NewClass.

  20. Creating a Java class • Enter a name for your class. • Eclipse reminds you of style rules here as well. • You can set the details of your class, including its superclasses, visibility and interfaces.

  21. Creating a Java class • Your new class appears in the Package Explorer beneath your package. • Eclipse also opens the source file for your class in the Java editor.

  22. A shortcut • You can create a new package and a new class at the same time. • Simply create a new class and enter a new package name in the wizard.

  23. Running your code • To run your code, right-click on the Java file, then choose Run AsJava Application.

  24. Running your code • Because this is a console application (it uses System.out.println), you'll see the output in the Console view. • By default, System.out is displayed in black, System.err is displayed in red and System.in shows up in green. • If the Console doesn't appear, you can open it through WindowShow View…

  25. Re-running your code • Once you've run your code, a reference to it appears in the Run menu. You can click your program's name in the Run History menu to run it again. • Run Last Launched (Ctrl+F11) does the same thing.

  26. Creating a run configuration • In some cases you need a run configuration. • This lets you set command-line parameters, JVM options, etc. • Select your project in the Package Explorer, then choose RunRun…

  27. Scrapbook pages • You can create a scrapbook page with the Java tools. A scrapbook page lets you enter and execute lines of Java code without building a class to hold them. • The wizard to create a new scrapbook page is under New JavaJava Run/Debug.

  28. Scrapbook pages • You can highlight some code, right-click on it, then choose Inspect, Display or Execute. • Our sample code here is System.out.println ("Here's the value of PI: " + Math.PI); • If you choose Execute, the selected code is executed. In this example, we've highlighted the entire line of code; executing it writes to the console.

  29. Scrapbook pages • If you choose Inspect, the scrapbook page shows you the value of whatever you've highlighted. • In this example, we've only highlighted Math.PI, not the whole line of code. • Display inserts the value of whatever you've highlighted.

  30. Automating testing with JUnit

  31. Automating testing with JUnit • JUnit was created by programming legends Kent Beck and Erich Gamma. • It makes it easy to implement Test-Driven Development (TDD), (sometimes called Test First Development). • Eclipse has JUnit support built in.

  32. Creating test cases • Right-click on a Java file and choose New Other…

  33. Creating test cases • Select Java/JUnit on the left and TestCase on the right, then click Next.

  34. Creating test cases • When you create a JUnit test case, you name the test case (it's a Java class) as well as the Java class tested by the test case.

  35. Creating test cases • Eclipse gives you a list of all the public methods in your class and its superclasses. You decide which ones should be part of the JUnit test class.

  36. Creating test cases • In this example, we ask Eclipse to generate a JUnit TestCase for the getGreeting() method. • The complete testGetGreeting() method is: public void testGetGreeting() { HelloWorld hw = new HelloWorld(); assertEquals("Hello, World!", hw.getGreeting()); } • We're saying that getGreeting() should always return the string "Hello, World!"

  37. Running test cases • Our test case is the Java class TestHelloWorld. • To run the class, select the test class in the Package Explorer, then choose Run AsJUnit Test.

  38. Running test cases • The results of running your test case appear in the JUnit view. • Green is good… • You can also create and run JUnit TestSuites. A TestSuite is an ordered collection of TestCases.

  39. Using JUnit • You define more TestCases and TestSuites as your project progresses. • You run the JUnit tests to make sure any changes you've made haven't broken your code.

  40. Using Ant and javadoc

  41. Using Ant • Ant (ant.apache.org) is an XML- and Java-based build tool. • Designed to have the same functionality as make without its quirks • You don't need a tab character at the start of each line, for example. • You can extend Ant to do other tasks if you want.

  42. Using Ant • An Ant build file (named build.xml by default) can define a number of targets. • You can define which target gets built from the command line (or the Eclipse equivalent), or let Ant figure out which one should be created.

  43. Using Ant • Once you've created your build.xml file (or whatever you choose to call it), you can right-click on it and choose Run Ant…

  44. Using javadoc • You can export your project to javadoc. • When you do this, Eclipse runs javadoc against your code and exports the generated files to the directory you choose.

  45. Using javadoc • When you generate the javadocs, you specify which packages and classes should be processed. • You can also decide which class members are processed (public, protected, private)

  46. Using javadoc • You can customize the files that are generated, such as index pages or navigation bars. • If you want, you can create links to the standard Java libraries.

  47. Using javadoc • The generated documentation is put in the docs folder of your project by default.

  48. Summary

  49. Summary • We've covered (although very quickly) the Java development functions in Eclipse, including: • Various automatic coding features • How to create and run Java code • Automating testing with JUnit • Using ant and javadoc inside Eclipse

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