CObserver.js 3.1 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118
  1. /*
  2. *+------------------------------------------------------------------------+
  3. *| Licensed Materials - Property of IBM
  4. *| IBM Cognos Products: Viewer
  5. *| (C) Copyright IBM Corp. 2001, 2011
  6. *|
  7. *| US Government Users Restricted Rights - Use, duplication or
  8. *| disclosure restricted by GSA ADP Schedule Contract with IBM Corp.
  9. *|
  10. *+------------------------------------------------------------------------+
  11. */
  12. /*-----------------------------------------------------------------------------------------------------
  13. Class : CObserver
  14. Description :
  15. -----------------------------------------------------------------------------------------------------*/
  16. function CObserver(subject) {
  17. this.m_subject = subject;
  18. this.m_observers = [];
  19. }
  20. function CObserver_attach(observer, callback, evt) {
  21. // verify that when attaching an observer, the observer has implemented a 'update' function
  22. if(observer == null || typeof observer.update != "function") {
  23. alert('Notification Frame Work Error : attach failed');
  24. return false;
  25. }
  26. var stateChange = new CState(this.m_subject, observer, callback ? callback : null, evt ? evt : null);
  27. this.m_observers[this.m_observers.length] = stateChange;
  28. return true;
  29. }
  30. function CObserver_detach(observer) {
  31. }
  32. function CObserver_hasObserver(observer)
  33. {
  34. var bHasObserver = false;
  35. for (var idxObs = 0; idxObs < this.m_observers.length; idxObs++)
  36. {
  37. if (this.m_observers[idxObs].getObserver() == observer)
  38. {
  39. bHasObserver = true;
  40. break;
  41. }
  42. }
  43. return bHasObserver;
  44. }
  45. function CObserver_notify(evt) {
  46. var i = 0;
  47. if(typeof evt != "undefined" && evt != null) {
  48. for(i = 0; i < this.m_observers.length; ++i) {
  49. if(this.m_observers[i].getEvt() == evt) {
  50. var theObserver = this.m_observers[i].getObserver();
  51. var theCallback = this.m_observers[i].getCallback();
  52. var cachedHandler = theObserver.update;
  53. theObserver.update = theCallback;
  54. theObserver.update(this.m_observers[i]);
  55. theObserver.update = cachedHandler;
  56. }
  57. }
  58. } else {
  59. for(i = 0; i < this.m_observers.length; ++i) {
  60. this.m_observers[i].getObserver().update(this.m_observers[i].getSubject());
  61. }
  62. }
  63. }
  64. CObserver.prototype.attach = CObserver_attach;
  65. CObserver.prototype.detach = CObserver_detach;
  66. CObserver.prototype.notify = CObserver_notify;
  67. CObserver.prototype.hasObserver = CObserver_hasObserver;
  68. /*-----------------------------------------------------------------------------------------------------
  69. Class : CState
  70. Description :
  71. -----------------------------------------------------------------------------------------------------*/
  72. function CState(subject, observer, callback,evt) {
  73. this.m_subject = subject;
  74. this.m_observer = observer;
  75. this.m_callback = callback;
  76. this.m_evt = evt;
  77. }
  78. function CState_getObserver() {
  79. return this.m_observer;
  80. }
  81. function CState_getCallback() {
  82. return this.m_callback;
  83. }
  84. function CState_getSubject() {
  85. return this.m_subject;
  86. }
  87. function CState_getEvt() {
  88. return this.m_evt;
  89. }
  90. CState.prototype.getObserver = CState_getObserver;
  91. CState.prototype.getCallback = CState_getCallback;
  92. CState.prototype.getSubject = CState_getSubject;
  93. CState.prototype.getEvt = CState_getEvt;