Ciklum Java Saturday, Oct 29-2011

1. Bring the FUN back to Java development Set of tools, making development easier Illarion Kovalchuk © 2011

4. Approach Use the right tools! Keep It Simple Write less code, write clean code Always consider the context

5. Overview – the stuff I'd like to talk about

7. Guice

8. Guava

9. Useful Libraries http://code.google.com/p/mockito/ Mockito is a mocking framework that tastes really good. It lets you write beautiful tests with clean & simple API. Mockito doesn't give you hangover because the tests are very readable and they produce clean verification errors.

10. Useful Libraries - Mockito

11. Useful Libraries - Mockito

12. Useful Libraries - Mockito

13. Useful Libraries - Mockito SLIDE FOR THOSE, WHO CAN READ SO MUCH CODE

14. Useful Libraries Put simply, Guice alleviates the need for factories and the use of new in your Java code. Think of Guice's @Inject as the new new http://code.google.com/p/google-guice/ google-guice

15. Useful Libraries – google-guice public class BillingModule extends AbstractModule { @Override protected void configure () { bind( TransactionLog .class).to( Database TransactionLog .class); bind( CreditCardProcessor .class).to( Paypal CreditCardProcessor .class); bind( BillingService .class).to( Real BillingService .class); } } Setup

16. Useful Libraries – google-guice public class BillingModule extends AbstractModule { @Override protected void configure () { bind( TransactionLog .class).to( Database TransactionLog .class); bind( CreditCardProcessor .class).to( Paypal CreditCardProcessor .class); bind( BillingService .class).to( Real BillingService .class); } } Setup @Inject public RealBillingService ( CreditCardProcessor processor, TransactionLog log ) { this .processor = processor; this .log = log; } Inject

17. Useful Libraries – google-guice public class BillingModule extends AbstractModule { @Override protected void configure () { bind( TransactionLog .class).to( Database TransactionLog .class); bind( CreditCardProcessor .class).to( Paypal CreditCardProcessor .class); bind( BillingService .class).to( Real BillingService .class); } } Setup @Inject public RealBillingService ( CreditCardProcessor processor, TransactionLog log ) { this .processor = processor; this .log = log; } Inject public static void main( String [] args) { Injector injector = Guice .createInjector(new BillingModule ()); BillingService billingService = injector.getInstance( BillingService .class); ... } Launch!

18. Useful Libraries The Guava project contains several of Google's core libraries that we rely on in our Java-based projects: collections, caching, primitives support, concurrency libraries, common annotations, string processing, I/O, and so forth. guava-libraries http://code.google.com/p/guava-libraries/

19. Useful Libraries - guava-libraries Example 1: Objects public class Person { final String name, nickname; final Movie favMovie; @Override public boolean equals(Object object) { if (object instanceof Person) { Person that = ( Person ) object; return Objects .equal(this.name, that.name) && Objects .equal(this.nickname, that.nickname) && Objects .equal(this.favMovie, that.favMovie); } return false; } @Override public int hashCode() { return Objects .hashCode(name, nickname, favMovie); }

20. Useful Libraries - guava-libraries Example 2: Other useful things Preconditions .checkState(state == State .PLAYABLE, "Can't play movie; state is %s" , state); //will throw ISE with message … this.rating = Preconditio ns.checkNotNull(rating); //will throw NPE … //CharMatcher matcher = CharMatcher.is('x'); //CharMatcher matcher = CharMatcher.isNot('_'); //CharMatcher matcher = CharMatcher.oneOf("aeiou").negate(); CharMatcher matcher = CharMatcher .inRange('a', 'z').or(inRange('A', 'Z')); matcher.matchesAllOf(“some string”); matcher.matchesAnyOf(“other string”); … String s = Joiner.on(", ").join(episodesOnDisc); … StringBuilder sb = ...; Joiner .on("|").skipNulls().appendTo(sb, episodesOnDisc);

21. Useful Libraries - guava-libraries Example 3: Collections2 List < Integer > integers = ... Collection < String > results; results = Collections2 . transform (integers, new Function < Integer , String >() { public String apply(Integer input) { return Integer.toString(input*2); } }); Collection < Integer > evens; evens = Collections2 . filter (integers, new Predicate < Integer >() { public boolean apply( Integer input) { return 0 == input % 2; } });

23. ecl Emma

24. XMind

26. Marks methods under test.

27. Jump to a test via the menu or Ctrl+J

28. Run a test from the class via the menu or Ctrl-R

29. Rename classes/methods.

30. Move classes and MoreUnit will move the corresponding test cases.

31. Generate a test class/method. http://moreunit.sourceforge.net/

33. Coverage results are immediately summarized and highlighted.

34. Does not require modifying projects or performing any other setup. EclEmma is a free Java code coverage tool for Eclipse http://www.eclemma.org/index.html http://emma.sourceforge.net/

36. Powerful tool to organize your thoughts XMind is your friend! http://www.xmind.net/

38. Verbose unit tests

39. Do not write so many unit tests, as they tell you!

40. Avoid string-typing

42. Hard to read – what is that null parameter for, or what's 5?

45. Easy to read

46. Can have checks in build(), to ensure the result correctness.

47. Result can have no setters or modifiers – safe to work with.

48. Coding techniques Verbose unit tests @Test public void testProcess(){ … } @Test public void testRegister(){ … } …

49. Coding techniques Verbose unit tests @Test public void process Should FailOnNull(){…} @Test public void process Should WorkOnEmptyString(){…} @Test public void process Should CheckSemicolons(){…} … @Test public void register Should FailOnNull(){…} @Test public void register Should CallProcess (){…} … Friend of you the “ SHOULD ” is @Test public void testProcess(){ … } @Test public void testRegister(){ … } …

50. Coding techniques Do not write so many unit tests as they tell you “ Cargo cult programming is a style of computer programming that is characterized by the ritual inclusion of code or program structures that serve no real purpose. ” Wikipedia Wikipedia 100% code coverage

52. Tests quantity != tests quality

53. The fact that the line of code was called is just a “smoke test”

54. Unit tests cannot replace other tests

55. Coding techniques Avoid String-typing public class User { … public User(String login, String password, String home, String shell) { … } … } String login = … String password = … String home = … String shell = … User user = new User(login, password, home, shell); User user = new User(password, home, login, “ “);

56. Coding techniques Avoid String-typing public class User { … public User(Login login, Password password, Home home, Shell shell) { … } … } Login login = … Password password = … Home home = … Shell shell = … User user = new User(login, password, home, shell); User user = new User(password, home, login, “ “); // – will not compile Or use a builder pattern, keeping String as type of all these parameters