My presentation on concurrency at GeeCON 2011

5. # of cores Today Soon

18. Tree traversal

19. File scan / search

24. No live-locks

28. df .y = 5

29. }

30. assert 15 == df .z

31. Composing async functions int hash1 = hash(download( 'http://www.gpars.org' )) int hash2 = hash(loadFile( '/gpars/website/index.html' )) boolean result = compare(hash1, hash2) println result

32. Composing async functions def hash = oldHash.asyncFun() def compare = oldCompare.asyncFun() def download = oldDownload.asyncFun() def loadFile = oldLoadFile.asyncFun() def hash1 = hash(download( 'http://www.gpars.org' )) def hash2 = hash(loadFile( '/gpars/website/index.html' )) def result = compare(hash1, hash2) println result .get()

33. Composing async functions int hash(String text ) {…} Promise<int> hash( Promise<String> | String text )

35. Wait (non-blocking) for the text param

36. Call the original hash()

37. Bind the result }

38. Composing async functions Combine functions as usual Parallelism is detected automatically

40. Fork/Join

41. Parallel collection processing

42. Dataflow variables/streams

45. Send a message

48. public void onMessage(String msg ) {

49. String encripted = encrypt( msg );

50. reply( encripted );

51. }

52. public void onMessage(Integer number ) {

53. reply(2 * number );

54. }

55. public void onMessage(Money cash ) {

56. System.out.println( &quot;Received a donation &quot; + cash );

57. account .deposit( cash );

58. }

59. }

60. Active Objects @ActiveObject class MyCounter { private int counter = 0 @ActiveMethod def incrementBy( int value) { println &quot;Received an integer: $value &quot; this .counter += value } }

63. Jon Kerridge, Napier University

66. http://www.jroller.com/vaclav

67. http://twitter.com/vaclav_pech