Extending a Base Product for Multiple Customers

Details how MediaGeniX builds customised, made-to-measure software for its customers.

Transcript

1. ESUG 2012
   Extending a Base Product
   for Multiple Customers
   Denis Defreyne
   MediaGeniX NG
   1
   

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2. View Slide

3. “ Your product is cool,
   but it’s missing feature X!
   3
   — CUSTOMER
   

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4. “
   Yes, feature X would be nice…
   for you, but nobody else!
   4
   — YOU
   

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5. “Why did you not
   implement feature X? :(
   5
   — CUSTOMER
   

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6. “Ugh, this product is
   getting bloated! :(
   6
   — OTHER CUSTOMER
   

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7. Contents
   1. Customisations
   2. Techniques
   3. Modules
   7
   

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8. 1. Customisations
   8
   

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9. Customisation =
   extra bits of code
   for a single customer
   9
   

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10. Customisations
    10
    ‣ New functionality
    e.g. new issue checks (no porn at noon)
    ‣ Extended functionality
    e.g. extra metadata on films, contracts, …
    ‣ Changed functionality
    e.g. parental rating management in UK, Finland
    

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11. Integrations
    11
    ‣ Playout server
    ‣ Commercial scheduling system
    ‣ Music scheduling system
    ‣ …
    unique for every customer!
    

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12. Customisations are
    only possible if you
    have FEW customers
    12
    

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13. Requirements
    ‣ Be customer-specific
    ‣ Be fine-grained
    ‣ Allow merging bugfixes
    ‣ Be decoupled
    13
    

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14. Why?
    14
    ‣ Talk to other devices
    You’ll have static on your TV otherwise
    ‣ Cater to a diverse market
    No two broadcasters have the same workflow
    ‣ Resolve conflicting requirements
    Don’t compromise, let them both have it their way
    ‣ Make customers happy!
    But don’t over-do it :)
    

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16. 2. Techniques
    16
    

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17. Techniques
    17
    1. Site classes
    2. Behaviors
    3. Convenience methods
    

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18. Techniques
    18
    1. Site classes
    2. Behaviors
    3. Convenience methods
    

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19. Site classes – example
    19
    

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20. Site classes – example
    20
    

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21. Site class =
    subclass for one
    specific customer
    21
    

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22. Site = customer
    22
    

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23. Site classes
    23
    Film
    

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24. Site classes
    24
    Film
    FilmMTV
    

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25. MTV
    Site classes
    25
    Film  class  >>  siteClassForMTV
    ^FilmMTV
    

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26. BASE
    Site classes
    26
    newAustinPowersFilm
    ^Film  siteClass  new
    title:  'Adventures  at  ESUG';
    duration:  (Duration  fromMinutes:  93);
    yourself
    

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27. WHATS’On code for MTV only
    Packages
    27
    MTV
    BASE
    FRAMEWORK
    WHATS’On code shared between customers
    MediaGeniX framework code
    

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28. Packages
    28
    MTV
    VTM
    VRT
    TV2
    NRK
    SBS FI NPO
    VPRO
    PRO7
    FOX FTO …
    

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29. Extensions in packages
    29
    PACKAGE A
    MusicClip
    MusicClip>>title
    MusicClip>>videoFile
    MusicClip>>audioFile
    MusicClip>>is16Plus
    PACKAGE B
    MusicClip>>contract
    MusicClip>>agency
    Contract
    Agreement
    

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30. MTV
    Site classes
    30
    Film  class  >>  siteClassForMTV
    ^FilmMTV
    

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31. Site classes
    31
    BASE
    Film
    MusicClip
    Commercial
    MTV
    FilmMTV
    Film>>siteClassForMTV
    

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32. Film  >>  siteClassForMTV
    Film  siteClass  new
    32
    

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33. FRAMEWORK
    Site classes
    33
    Class  >>  siteClass
    ^Site  current  siteClassOf:  self
     
    

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34. MTV
    Site classes
    34
    SiteMTV  >>  siteClassOf:  aClass
    ^aClass  siteClassForMTV
     
     
    

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35. BASE
    Site classes
    35
    Site  >>  siteClassOf:  aClass
    ^aClass
    

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36. BASE
    Site classes – example
    36
    Film  class  >>  buildSuperModelWith:  aBuilder
    super  buildSuperModelWith:  aBuilder.
    aBuilder
    addString:  #title  name:  'Title';
    addDuration:  #duration  name:  'Duration'
    

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38. BASE
    Site classes – example
    38
    Film  class  >>  buildSuperModelWith:  aBuilder
    super  buildSuperModelWith:  aBuilder.
    aBuilder
    addString:  #title  name:  'Title';
    addDuration:  #duration  name:  'Duration'
    

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39. MTV
    Site classes – example
    39
    FilmMTV  class  >>  buildSuperModelWith:  aBuilder
    super  buildSuperModelWith:  aBuilder.
    aBuilder
    addString:  #idForMTV  name:  'ID  for  MTV'
    

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40. Site classes – example
    40
    

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41. Site classes – example
    41
    

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42. BASE
    Site classes – example
    42
    FilmEditor  class  >>  form
    ^self  newForm
    addFormField:  #title;
    addFormField:  #duration;
    yourself
    

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43. MTV
    Site classes – example
    43
    FilmEditor  >>  siteClassForMTV
    ^FilmEditorMTV
    FilmEditorMTV  class  >>  form
    ^super  form
    addFormField:  #idForMTV;
    yourself
    

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44. Site classes – example
    44
    

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45. Site classes – example
    45
    

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46. BASE
    Site classes – example
    46
    FilmEditor  class  >>  form
    ^self  newForm
    addFormField:  #title;
    addFormField:  #duration;
    addFormField:  #imdbRating;
    yourself
    

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47. Site classes – example
    47
    

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48. Site classes – example
    48
    

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49. BASE
    Site classes – example
    49
    Film  >>  openInEditor
    ^FilmEditor  siteClass
    openWithEditee:  self
    

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50. Call #siteClass everywhere?
    50
    YES!
    It’s not as bad as you may think…
    

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51. PRO TIP
    Avoid long methods
    51
    

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52. Techniques
    52
    1. Site classes
    2. Behaviors
    3. Convenience methods
    

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53. Behaviors
    53
    Product
    Film Commercial MusicClip
    

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54. Product
    ProductMTV
    Behaviors
    54
    

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55. Behaviors
    55
    Product
    Film Commercial MusicClip
    

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56. Behaviors
    56
    Product
    Film Commercial MusicClip
    ProductBehavior
    ProductBehaviorMTV
    

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57. Behavior class =
    siteclassable class with
    behavior from original class
    57
    

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58. FRAMEWORK
    Behaviors
    58
    BehaviorObject  class  >>  newOn:  anObject
    ^self  new
    orig:  anObject;
    yourself
    

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59. BASE
    Behaviors – example
    59
    Product  >>  hasValidCertForTx:  aTx
    ^self  certification  isOkayForTx:  aTx
    

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60. BASE
    Behaviors – example
    60
    ProductBehavior  >>  hasValidCertForTx:  aTx
    ^self  orig  certification  isOkayForTx:  aTx
    

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61. MTV
    Behaviors – example
    61
    ProductBehaviorMTV  >>  hasValidCertForTx:  aTx
    ^self  orig  videoFiles  allSatisfy:
    [:f  |  f  certification  isOkayForTx:  aTx]
    

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62. BASE
    Behaviors – example
    62
    Product  >>  hasValidCertForTx:  aTx
    ^self  behavior  hasValidCertForTx:  aTx
    

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63. BASE
    Behaviors – example
    63
    Product  >>  behavior
    behavior  ifNil:
       [behavior  :=  ProductBehavior  siteClass
           newOn:  self].
    ^behavior
    

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64. PRO TIP
    64
    Prefer composition
    over inheritance
    

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65. Techniques
    65
    1. Site classes
    2. Behaviors
    3. Convenience methods
    

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66. Convenience method =
    commonly implemented
    or overridden method
    66
    

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67. Convenience methods
    67
    buildSuperModelWith:  aBuilder
    addToolsMenuItemsTo:  aMenu
    addCommandsToToolBar:  aToolBar
    

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68. Convenience methods
    68
    buildSuperModelWith:  aBuilder
    buildSuperModelForMTVWith:  aBuilder
    addToolsMenuItemsTo:  aMenu
    addToolsMenuItemsForMTVTo:  aMenu
    addCommandsToToolBar:  aToolBar
    addCommandsToToolBarForMTV:  aToolBar
    

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69. MTV
    Convenience methods
    69
    FilmMTV  class  >>  buildSuperModelWith:  aBuilder
    super  buildSuperModelWith:  aBuilder.
    aBuilder
    addString:  #idForMTV  name:  'ID  for  MTV'
    

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70. MTV
    Convenience methods
    70
    Film  class  >>  buildSuperModelForMTVWith:  aBuilder
    super  buildSuperModelForMTVWith:  aBuilder.
    aBuilder
    addString:  #idForMTV  name:  'ID  for  MTV'
    

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71. FRAMEWORK
    Convenience methods
    71
    Site  >>  buildSuperModelWith:  aBuilder
                   for:  aClass
    aClass  buildSuperModelWith:  aBuilder
    

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72. MTV
    Convenience methods
    72
    SiteMTV  >>  buildSuperModelWith:  aBuilder
                         for:  aClass
    super  buildSuperModelWith:  aBuilder  for:  aClass.
    aClass  buildSuperModelForMTVWith:  aBuilder.
    

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73. PRO TIP
    73
    Use convenience methods
    for common methods only
    

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74. Techniques to avoid
    ‣ Branches
    Use them, but not for customer-specific code
    ‣ VisualWorks “overrides”
    They prevent access to original code
    74
    

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75. Techniques
    75
    1. Site classes
    2. Behaviors
    3. Convenience methods
    

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76. 3. Modules
    76
    

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77. Module =
    pluggable component
    that provides a set of
    related functionalities
    77
    

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78. Example modules
    ‣ Contract management
    ‣ Secondary events (logos)
    ‣ Video on demand
    78
    

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79. BASE
    Super models in modules
    79
    Film  class  >>  buildSuperModelWith:  aBuilder
    super
    buildSuperModelWith:  aBuilder.
    aBuilder
    "  …  other  attributes  here  …  "
    addReference:  #contract
    to:  Contract  name:  'Contract'
    W R O N G
    

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80. MTV
    Activating modules
    SiteMTV  >>  moduleClasses
    ^OrderedCollection  new
    add:  ContractModule;
    add:  SecondaryEventsModule;
    yourself
    80
    

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81. Super models in modules
    81
    

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82. BASE
    Super models in modules
    82
    Film  class  >>
    buildSuperModelForContractModuleWith:  aBuilder
    super
    buildSuperModelForContractModuleWith:  aBuilder.
    aBuilder
    addReference:  #contract
    to:  Contract  name:  'Contract'
    

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83. FRAMEWORK
    Super models in modules
    83
    Site  >>  buildSuperModelWith:  aBuilder
                   for:  aClass
    aClass  buildSuperModelWith:  aBuilder.
    

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84. FRAMEWORK
    Super models in modules
    84
    Site  >>  buildSuperModelWith:  aBuilder
                   for:  aClass
    aClass  buildSuperModelWith:  aBuilder.
    self  modules  do:
    [:m  |
    m  buildSuperModelWith:  aBuilder  for:  aClass].
    

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85. FRAMEWORK
    Super models in modules
    85
    Module  >>  buildSuperModelWith:  aBuilder
                       for:  aClass
    "nothing  by  default"
    

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86. BASE
    Super models in modules
    86
    ContractPresentModule  >>  buildSuperModelWith:  aBuilder
                                                     for:  aClass
    aClass  buildSuperModelForContractModuleWith:
    aBuilder.
    

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87. Extensions in modules
    87
    

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88. BASE
    Extensions in modules
    88
    FilmEditor  class  >>  form
    form  :=  self  newForm.
    form  addFormField:  #title.
    form  addFormField:  #duration.
    ^form
    

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89. BASE
    Extensions in modules
    89
    FilmEditor  class  >>  form
    form  :=  self  newForm.
    form  addFormField:  #title.
    form  addFormField:  #duration.
    form  addFormField:  #contract.
    ^form
    W R O N G
    

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90. BASE
    Extensions in modules
    90
    FilmEditor  class  >>  form
    form  :=  self  newForm.
    form  addFormField:  #title.
    form  addFormField:  #duration.
    ContractModule  current
    addFieldsTo:  form  for:  self.
    ^form
    

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91. BASE
    Extensions in modules
    91
    ContractPresentModule  >>
       addFieldsTo:  aForm
       for:  anEditor
    anEditor  addContractFieldsTo:  aForm
    

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92. BASE
    Extensions in modules
    92
    FilmEditor  >>
       addContractFieldsTo:  aForm
       aForm  addFormField:  #contract.
    

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93. BASE
    Extensions in modules
    93
    ContractAbsentModule  >>
       addFieldsTo:  aForm
       for:  aSender
       "nothing  by  default"
    

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94. Extensions in modules
    94
    CONTRACT
    

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95. Extensions in modules
    95
    CONTRACT
    

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96. Site classes vs. modules
    96
    ‣ Modules can be shared across sites
    ‣ Modules require hooks
    

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97. Recap
    97
    

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98. Techniques
    98
    ‣ Use site classes
    whenever possible
    ‣ Use behaviors
    when site classes fail (inheritance trees)
    ‣ Use modules
    when you need more separation
    

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99. Requirements
    ‣ Be customer-specific (with packages)
    ‣ Be fine-grained (with site classes)
    ‣ Allow merging bugfixes (with packages)
    ‣ Be decoupled (with site classes and modules)
    99
    

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100. 100
     “ Your product is cool,
     but it’s missing feature X!
     — CUSTOMER
     Do not worry.
     We’ll implement it for you!
     — YOU
     

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101. 101
     ?
     MAIL denis.defreyne@mediagenix.tv
     TWITTER @ddfreyne
     GITHUB github.com/ddfreyne
     

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102. Extra Slides
     102
     

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103. FRAMEWORK
     Site classing modules
     103
     Site  >>  modules
     ^self  moduleClasses  collect:
     [:c  |  c  siteClass  new]
     

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104. FRAMEWORK
     Site classing modules
     104
     SuperModellary  >>  buildSuperModelFor:  aClass
        builder  :=  SuperModelBuilder  new.
        Site  current  buildSuperModelWith:  builder
            for:  aClass.
        supermodels  at:  aClass  put:  builder  superModel.
     

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105. BASE
     Extensions in modules
     105
     FilmEditor  class  >>  form
     form  :=  self  newForm.
     form  addFormField:  #title.
     form  addFormField:  #duration.
     ContractModule  current
     addFieldsTo:  form  for:  self.
     ^form
     

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106. BASE
     Extensions in modules
     106
     FilmEditor  class  >>  form
     form  :=  self  newForm.
     form  addFormField:  #title.
     form  addFormField:  #duration.
     ContractModule  current  isAvailable  ifTrue:
     [form  addFormField:  #contract].
     ^form
     

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107. BASE
     Extensions in modules
     107
     Film  >>  isLegallyBroadcastable
     ^ContractModule  current  isAvailable
     ifFalse:  [true]
     ifTrue:  [self  contract  isSigned].
     

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108. BASE
     Extensions in modules
     108
     Film  >>  isLegallyBroadcastable
     ^ContractModule  current  isAvailable
     ifFalse:  [true]
     ifTrue:  [self  contract  isSigned].
     

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109. BASE
     Extensions in modules
     109
     Film  >>  isLegallyBroadcastable
     ^ContractModule  current
     isFilmLegallyBroadcastable:  self
     

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110. BASE
     Extensions in modules
     110
     ContractPresentModule  >>
        isFilmLegallyBroadcastable:  aFilm
     ^aFilm  contract  isSigned
     

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111. BASE
     Extensions in modules
     111
     ContractAbsentModule  >>
        isFilmLegallyBroadcastable:  aFilm
     ^true
     

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