Groovy in 2014 and beyond -- JavaOne 2014

The latest developments in the Groovy programming language proejct

Transcript

1. Groovy
   in 2014
   and beyond
   Guillaume Laforge
   Groovy project lead
   Pivotal
   @glaforge
   

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2. Stay up-to-date
   Groovy Weekly Newsletter (Every Tuesday)
   http://beta.groovy-lang.org/groovy-weekly.html
   2
   

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3. The Groovy roadmap
   3
   2015
   2014
   2013
   Groovy 2.3
   Groovy 2.4
   Groovy 2.2
   Groovy 2.5 ?
   Groovy 3.0 ?
   

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4. @glaforge — Groovy in 2014 and beyond
   Groovy 2.3
   

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5. @glaforge — Groovy in 2014 and beyond
   JDK 8 support
   

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6. JDK 8 support — closures vs lambdas
   6
   IntStream.range(1,  100).forEach(s  -­‐>      
                                            System.out.println(s));  
   !
   Files.lines(Paths.get('README.adoc'))  
            .map(it  -­‐>  it.toUpperCase())  
            .forEach(it  -­‐>  System.out.println(it));
   

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7. JDK 8 support — closures vs lambdas
   6
   IntStream.range(1,  100).forEach(s  -­‐>      
                                            System.out.println(s));  
   !
   Files.lines(Paths.get('README.adoc'))  
            .map(it  -­‐>  it.toUpperCase())  
            .forEach(it  -­‐>  System.out.println(it));
   IntStream.range(1,  100).forEach  {  println  it  }  
   !
   Files.lines(Paths.get('README.adoc'))  
            .map  {  it.toUpperCase()  }  
            .forEach  {  println  it  }
   

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8. JDK 8 support — closures vs lambdas
   6
   IntStream.range(1,  100).forEach(s  -­‐>      
                                            System.out.println(s));  
   !
   Files.lines(Paths.get('README.adoc'))  
            .map(it  -­‐>  it.toUpperCase())  
            .forEach(it  -­‐>  System.out.println(it));
   IntStream.range(1,  100).forEach  {  println  it  }  
   !
   Files.lines(Paths.get('README.adoc'))  
            .map  {  it.toUpperCase()  }  
            .forEach  {  println  it  }
   Use Groovy closures
   wherever you pass
   lambdas in Java 8
   

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9. @glaforge — Groovy in 2014 and beyond
   Traits
   

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10. Traits
    • Like interfaces, but with method bodies
    • similar to Java 8 interface default methods
    
    • Elegant way to compose behavior
    
    • multiple inheritance without the « diamond » problem
    
    • Traits can also be stateful
    
    • traits can have properties like normal classes
    
    • Compatible with static typing and static compilation
    • class methods from traits also visible from Java classes
    
    • Also possible to implement traits at runtime 8
    

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11. Traits: a simple example
    9
    trait  FlyingAbility  {  
           String  fly()  {  "I'm  flying!"  }  
    }  
    !
    class  Bird  implements  FlyingAbility  {}  
    def  b  =  new  Bird()  
    !
    assert  b.fly()  ==  "I'm  flying!"
    

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12. Traits: a simple example
    9
    trait  FlyingAbility  {  
           String  fly()  {  "I'm  flying!"  }  
    }  
    !
    class  Bird  implements  FlyingAbility  {}  
    def  b  =  new  Bird()  
    !
    assert  b.fly()  ==  "I'm  flying!"
    « trait », a new keyword
    for a new concept
    

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13. Traits: a simple example
    9
    trait  FlyingAbility  {  
           String  fly()  {  "I'm  flying!"  }  
    }  
    !
    class  Bird  implements  FlyingAbility  {}  
    def  b  =  new  Bird()  
    !
    assert  b.fly()  ==  "I'm  flying!"
    a class 

    « implements »

    a trait
    

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14. Traits: a simple example
    9
    trait  FlyingAbility  {  
           String  fly()  {  "I'm  flying!"  }  
    }  
    !
    class  Bird  implements  FlyingAbility  {}  
    def  b  =  new  Bird()  
    !
    assert  b.fly()  ==  "I'm  flying!"
    the fly() method from
    the trait is available
    

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15. Traits: a simple example
    9
    trait  FlyingAbility  {  
           String  fly()  {  "I'm  flying!"  }  
    }  
    !
    class  Bird  implements  FlyingAbility  {}  
    def  b  =  new  Bird()  
    !
    assert  b.fly()  ==  "I'm  flying!"
    

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16. Traits: stateful
    10
    trait  Named  {  
           String  name  
    }  
    !
    class  Bird  implements  Named  {}  
    def  b  =  new  Bird(name:  'Colibri')  
    !
    assert  b.name  ==  'Colibri'
    

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17. Traits: stateful
    10
    trait  Named  {  
           String  name  
    }  
    !
    class  Bird  implements  Named  {}  
    def  b  =  new  Bird(name:  'Colibri')  
    !
    assert  b.name  ==  'Colibri'
    a Groovy property
    

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18. Traits: stateful
    10
    trait  Named  {  
           String  name  
    }  
    !
    class  Bird  implements  Named  {}  
    def  b  =  new  Bird(name:  'Colibri')  
    !
    assert  b.name  ==  'Colibri'
    implement the trait
    

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19. Traits: stateful
    10
    trait  Named  {  
           String  name  
    }  
    !
    class  Bird  implements  Named  {}  
    def  b  =  new  Bird(name:  'Colibri')  
    !
    assert  b.name  ==  'Colibri'
    Groovy named
    argument constructor
    

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20. Traits: stateful
    10
    trait  Named  {  
           String  name  
    }  
    !
    class  Bird  implements  Named  {}  
    def  b  =  new  Bird(name:  'Colibri')  
    !
    assert  b.name  ==  'Colibri'
    access the property
    

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21. Traits: stateful
    10
    trait  Named  {  
           String  name  
    }  
    !
    class  Bird  implements  Named  {}  
    def  b  =  new  Bird(name:  'Colibri')  
    !
    assert  b.name  ==  'Colibri'
    

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22. Traits: inheritance
    11
    trait  Named  {  String  name  }  
    !
    trait  FlyingAbility  extends  Named  {  
           String  fly()  {  "I'm  a  flying  ${name}!"  }  
    }  
    !
    class  Bird  implements  FlyingAbility  {}  
    def  b  =  new  Bird(name:  'Colibri')  
    !
    assert  b.name  ==  'Colibri'  
    assert  b.fly()  ==  "I'm  a  flying  Colibri!"
    

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23. Traits: inheritance
    11
    trait  Named  {  String  name  }  
    !
    trait  FlyingAbility  extends  Named  {  
           String  fly()  {  "I'm  a  flying  ${name}!"  }  
    }  
    !
    class  Bird  implements  FlyingAbility  {}  
    def  b  =  new  Bird(name:  'Colibri')  
    !
    assert  b.name  ==  'Colibri'  
    assert  b.fly()  ==  "I'm  a  flying  Colibri!"
    extend the Named trait
    

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24. Traits: inheritance
    11
    trait  Named  {  String  name  }  
    !
    trait  FlyingAbility  extends  Named  {  
           String  fly()  {  "I'm  a  flying  ${name}!"  }  
    }  
    !
    class  Bird  implements  FlyingAbility  {}  
    def  b  =  new  Bird(name:  'Colibri')  
    !
    assert  b.name  ==  'Colibri'  
    assert  b.fly()  ==  "I'm  a  flying  Colibri!"
    access the name property
    

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25. Traits: inheritance
    11
    trait  Named  {  String  name  }  
    !
    trait  FlyingAbility  extends  Named  {  
           String  fly()  {  "I'm  a  flying  ${name}!"  }  
    }  
    !
    class  Bird  implements  FlyingAbility  {}  
    def  b  =  new  Bird(name:  'Colibri')  
    !
    assert  b.name  ==  'Colibri'  
    assert  b.fly()  ==  "I'm  a  flying  Colibri!"
    implement the
    composite trait
    

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26. Traits: inheritance
    11
    trait  Named  {  String  name  }  
    !
    trait  FlyingAbility  extends  Named  {  
           String  fly()  {  "I'm  a  flying  ${name}!"  }  
    }  
    !
    class  Bird  implements  FlyingAbility  {}  
    def  b  =  new  Bird(name:  'Colibri')  
    !
    assert  b.name  ==  'Colibri'  
    assert  b.fly()  ==  "I'm  a  flying  Colibri!"
    

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27. Traits: what about conflicts?
    12
    trait  KiteSurfer  {  String  surf()  {  'kite'  }  }  
    !
    trait  WebSurfer    {  String  surf()  {    'web'  }  }  
    !
    class  Person  {  String  name  }  
    !
    class  Hipster  extends  Person  
                         implements  KiteSurfer,  WebSurfer  {}  
    !
    def  h  =  new  Hipster()  
    assert  h.surf()  ==  'web'
    

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28. Traits: what about conflicts?
    12
    trait  KiteSurfer  {  String  surf()  {  'kite'  }  }  
    !
    trait  WebSurfer    {  String  surf()  {    'web'  }  }  
    !
    class  Person  {  String  name  }  
    !
    class  Hipster  extends  Person  
                         implements  KiteSurfer,  WebSurfer  {}  
    !
    def  h  =  new  Hipster()  
    assert  h.surf()  ==  'web'
    two surf() methods
    

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29. Traits: what about conflicts?
    12
    trait  KiteSurfer  {  String  surf()  {  'kite'  }  }  
    !
    trait  WebSurfer    {  String  surf()  {    'web'  }  }  
    !
    class  Person  {  String  name  }  
    !
    class  Hipster  extends  Person  
                         implements  KiteSurfer,  WebSurfer  {}  
    !
    def  h  =  new  Hipster()  
    assert  h.surf()  ==  'web'
    

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30. Traits: what about conflicts?
    12
    trait  KiteSurfer  {  String  surf()  {  'kite'  }  }  
    !
    trait  WebSurfer    {  String  surf()  {    'web'  }  }  
    !
    class  Person  {  String  name  }  
    !
    class  Hipster  extends  Person  
                         implements  KiteSurfer,  WebSurfer  {}  
    !
    def  h  =  new  Hipster()  
    assert  h.surf()  ==  'web'
    extending a class and
    implementing the two traits
    

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31. Traits: what about conflicts?
    12
    trait  KiteSurfer  {  String  surf()  {  'kite'  }  }  
    !
    trait  WebSurfer    {  String  surf()  {    'web'  }  }  
    !
    class  Person  {  String  name  }  
    !
    class  Hipster  extends  Person  
                         implements  KiteSurfer,  WebSurfer  {}  
    !
    def  h  =  new  Hipster()  
    assert  h.surf()  ==  'web'
    

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32. Traits: what about conflicts?
    12
    trait  KiteSurfer  {  String  surf()  {  'kite'  }  }  
    !
    trait  WebSurfer    {  String  surf()  {    'web'  }  }  
    !
    class  Person  {  String  name  }  
    !
    class  Hipster  extends  Person  
                         implements  KiteSurfer,  WebSurfer  {}  
    !
    def  h  =  new  Hipster()  
    assert  h.surf()  ==  'web'
    last declared trait wins!
    

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33. Traits: what about conflicts?
    12
    trait  KiteSurfer  {  String  surf()  {  'kite'  }  }  
    !
    trait  WebSurfer    {  String  surf()  {    'web'  }  }  
    !
    class  Person  {  String  name  }  
    !
    class  Hipster  extends  Person  
                         implements  KiteSurfer,  WebSurfer  {}  
    !
    def  h  =  new  Hipster()  
    assert  h.surf()  ==  'web'
    

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34. Traits: what about conflicts?
    13
    trait  KiteSurfer  {  String  surf()  {  'kite'  }  }  
    !
    trait  WebSurfer    {  String  surf()  {    'web'  }  }  
    !
    class  Person  {  String  name  }  
    !
    class  Hipster  extends  Person  
                         implements  WebSurfer,  KiteSurfer  {}  
    !
    def  h  =  new  Hipster()  
    assert  h.surf()  ==  'kite'
    

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35. Traits: what about conflicts?
    13
    trait  KiteSurfer  {  String  surf()  {  'kite'  }  }  
    !
    trait  WebSurfer    {  String  surf()  {    'web'  }  }  
    !
    class  Person  {  String  name  }  
    !
    class  Hipster  extends  Person  
                         implements  WebSurfer,  KiteSurfer  {}  
    !
    def  h  =  new  Hipster()  
    assert  h.surf()  ==  'kite'
    reverse the order!
    

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36. Traits: what about conflicts?
    13
    trait  KiteSurfer  {  String  surf()  {  'kite'  }  }  
    !
    trait  WebSurfer    {  String  surf()  {    'web'  }  }  
    !
    class  Person  {  String  name  }  
    !
    class  Hipster  extends  Person  
                         implements  WebSurfer,  KiteSurfer  {}  
    !
    def  h  =  new  Hipster()  
    assert  h.surf()  ==  'kite'
    

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37. Traits: what about conflicts?
    14
    trait  KiteSurfer  {  String  surf()  {  'kite'  }  }  
    !
    trait  WebSurfer    {  String  surf()  {    'web'  }  }  
    !
    class  Person  {  String  name  }  
    !
    class  Hipster  extends  Person  
                         implements  WebSurfer,  KiteSurfer  {  
           String  surf()  {  KiteSurfer.super.surf()  }  
    }  
    !
    def  h  =  new  Hipster()  
    assert  h.surf()  ==  'kite'
    

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38. Traits: what about conflicts?
    14
    trait  KiteSurfer  {  String  surf()  {  'kite'  }  }  
    !
    trait  WebSurfer    {  String  surf()  {    'web'  }  }  
    !
    class  Person  {  String  name  }  
    !
    class  Hipster  extends  Person  
                         implements  WebSurfer,  KiteSurfer  {  
           String  surf()  {  KiteSurfer.super.surf()  }  
    }  
    !
    def  h  =  new  Hipster()  
    assert  h.surf()  ==  'kite'
    Be explicit!
    Override surf() 

    & use ‘super’
    

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39. Traits: what about conflicts?
    14
    trait  KiteSurfer  {  String  surf()  {  'kite'  }  }  
    !
    trait  WebSurfer    {  String  surf()  {    'web'  }  }  
    !
    class  Person  {  String  name  }  
    !
    class  Hipster  extends  Person  
                         implements  WebSurfer,  KiteSurfer  {  
           String  surf()  {  KiteSurfer.super.surf()  }  
    }  
    !
    def  h  =  new  Hipster()  
    assert  h.surf()  ==  'kite'
    Your class method takes
    precedence over the traits
    

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40. Traits: what about conflicts?
    14
    trait  KiteSurfer  {  String  surf()  {  'kite'  }  }  
    !
    trait  WebSurfer    {  String  surf()  {    'web'  }  }  
    !
    class  Person  {  String  name  }  
    !
    class  Hipster  extends  Person  
                         implements  WebSurfer,  KiteSurfer  {  
           String  surf()  {  KiteSurfer.super.surf()  }  
    }  
    !
    def  h  =  new  Hipster()  
    assert  h.surf()  ==  'kite'
    

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41. trait  Named  {  
           String  name  
    }  
    !
    class  Animal  {}  
    class  NamedAnimal  implements  Named  {}  
    !
    def  na  =  new  NamedAnimal(name:  'Felix')  
    !
    assert  na.name  ==  'Felix'
    Traits: runtime implementation
    15
    

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42. trait  Named  {  
           String  name  
    }  
    !
    class  Animal  {}  
    class  NamedAnimal  implements  Named  {}  
    !
    def  na  =  new  NamedAnimal(name:  'Felix')  
    !
    assert  na.name  ==  'Felix'
    Traits: runtime implementation
    15
    Somewhat artificial to have to
    create an intermediary class to
    get named animals
    

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43. trait  Named  {  
           String  name  
    }  
    !
    class  Animal  {}  
    class  NamedAnimal  implements  Named  {}  
    !
    def  na  =  new  NamedAnimal(name:  'Felix')  
    !
    assert  na.name  ==  'Felix'
    Traits: runtime implementation
    15
    

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44. trait  Named  {  
           String  name  
    }  
    !
    class  Animal  {}  
    !
    !
    def  na  =  new  Animal()  as  Named  
    na.name  =  'Felix'  
    assert  na.name  ==  'Felix'
    Traits: runtime implementation
    16
    

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45. trait  Named  {  
           String  name  
    }  
    !
    class  Animal  {}  
    !
    !
    def  na  =  new  Animal()  as  Named  
    na.name  =  'Felix'  
    assert  na.name  ==  'Felix'
    Traits: runtime implementation
    16
    Runtime trait, 

    with Groovy’s usual
    coercion mechanism
    

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46. trait  Named  {  
           String  name  
    }  
    !
    class  Animal  {}  
    !
    !
    def  na  =  new  Animal()  as  Named  
    na.name  =  'Felix'  
    assert  na.name  ==  'Felix'
    Traits: runtime implementation
    16
    

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47. Traits: runtime implementation
    17
    trait  Named  {  String  name  }  
    !
    trait  Quacks  {  
           String  quack()  {  'Quack!'  }  
    }  
    !
    class  Animal  {}  
    !
    def  na  =  new  Animal().withTraits  Named,  Quacks  
    na.name  =  'Daffy'  
    assert  na.name  ==  'Daffy'  
    assert  na.quack()  ==  'Quack!'
    

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48. Traits: runtime implementation
    17
    trait  Named  {  String  name  }  
    !
    trait  Quacks  {  
           String  quack()  {  'Quack!'  }  
    }  
    !
    class  Animal  {}  
    !
    def  na  =  new  Animal().withTraits  Named,  Quacks  
    na.name  =  'Daffy'  
    assert  na.name  ==  'Daffy'  
    assert  na.quack()  ==  'Quack!'
    Implement several traits at
    once, at runtime
    

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49. Traits: runtime implementation
    17
    trait  Named  {  String  name  }  
    !
    trait  Quacks  {  
           String  quack()  {  'Quack!'  }  
    }  
    !
    class  Animal  {}  
    !
    def  na  =  new  Animal().withTraits  Named,  Quacks  
    na.name  =  'Daffy'  
    assert  na.name  ==  'Daffy'  
    assert  na.quack()  ==  'Quack!'
    

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50. @glaforge — Groovy in 2014 and beyond
    AST transforms
    

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51. New: @TailRecursive
    19
    import  groovy.transform.TailRecursive  
    !
    @TailRecursive  
    def  fact(BigInteger  n,  accu  =  1G)  {  
           if  (n  <  2)  accu  
           else  fact(n  -­‐  1,  n  *  accu)  
    }  
    !
    assert  fact(1000)  >  10e2566
    

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52. New: @TailRecursive
    19
    import  groovy.transform.TailRecursive  
    !
    @TailRecursive  
    def  fact(BigInteger  n,  accu  =  1G)  {  
           if  (n  <  2)  accu  
           else  fact(n  -­‐  1,  n  *  accu)  
    }  
    !
    assert  fact(1000)  >  10e2566
    Rewrites tail recursive
    friendly function serially
    

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53. New: @TailRecursive
    19
    import  groovy.transform.TailRecursive  
    !
    @TailRecursive  
    def  fact(BigInteger  n,  accu  =  1G)  {  
           if  (n  <  2)  accu  
           else  fact(n  -­‐  1,  n  *  accu)  
    }  
    !
    assert  fact(1000)  >  10e2566
    Doesn’t blow up with a
    stack overflow error
    

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54. New: @TailRecursive
    19
    import  groovy.transform.TailRecursive  
    !
    @TailRecursive  
    def  fact(BigInteger  n,  accu  =  1G)  {  
           if  (n  <  2)  accu  
           else  fact(n  -­‐  1,  n  *  accu)  
    }  
    !
    assert  fact(1000)  >  10e2566
    Downside of tail recursion is 

    you might have to rewrite 

    your algo to be tailrec friendly
    

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55. New: @TailRecursive
    19
    import  groovy.transform.TailRecursive  
    !
    @TailRecursive  
    def  fact(BigInteger  n,  accu  =  1G)  {  
           if  (n  <  2)  accu  
           else  fact(n  -­‐  1,  n  *  accu)  
    }  
    !
    assert  fact(1000)  >  10e2566
    

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56. New: @Sortable
    20
    import  groovy.transform.*  
    !
    @Sortable  
    class  Person  {  
           String  lastName  
           String  firstName  
           int  age  
    }
    

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57. New: @Sortable
    20
    import  groovy.transform.*  
    !
    @Sortable  
    class  Person  {  
           String  lastName  
           String  firstName  
           int  age  
    }
    Makes the class Comparable
    by multiple Comparators
    

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58. New: @Sortable
    20
    import  groovy.transform.*  
    !
    @Sortable  
    class  Person  {  
           String  lastName  
           String  firstName  
           int  age  
    }
    First compare by lastName,
    then by firstName, etc.
    

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59. New: @Sortable
    20
    import  groovy.transform.*  
    !
    @Sortable  
    class  Person  {  
           String  lastName  
           String  firstName  
           int  age  
    }
    You can also specify
    ‘includes’ / ‘excludes’
    properties
    

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60. New: @Sortable
    20
    import  groovy.transform.*  
    !
    @Sortable  
    class  Person  {  
           String  lastName  
           String  firstName  
           int  age  
    }
    

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61. @BaseScript improvements
    21
    abstract  class  CustomBase  extends  Script  {  
           int  meaningOfLife  =  42  
    }
    @BaseScript(CustomBase)  
    import  groovy.transform.BaseScript  
    !
    assert  meaningOfLife  ==  42
    

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62. @BaseScript improvements
    21
    abstract  class  CustomBase  extends  Script  {  
           int  meaningOfLife  =  42  
    }
    @BaseScript(CustomBase)  
    import  groovy.transform.BaseScript  
    !
    assert  meaningOfLife  ==  42
    You can add your own base methods and
    properties to all compiled scripts
    

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63. @BaseScript improvements
    21
    abstract  class  CustomBase  extends  Script  {  
           int  meaningOfLife  =  42  
    }
    @BaseScript(CustomBase)  
    import  groovy.transform.BaseScript  
    !
    assert  meaningOfLife  ==  42
    Define the base script
    class for this script
    

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64. @BaseScript improvements
    21
    abstract  class  CustomBase  extends  Script  {  
           int  meaningOfLife  =  42  
    }
    @BaseScript(CustomBase)  
    import  groovy.transform.BaseScript  
    !
    assert  meaningOfLife  ==  42
    Ability to put the annotation on
    imports & package
    

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65. @BaseScript improvements
    21
    abstract  class  CustomBase  extends  Script  {  
           int  meaningOfLife  =  42  
    }
    @BaseScript(CustomBase)  
    import  groovy.transform.BaseScript  
    !
    assert  meaningOfLife  ==  42
    

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66. @BaseScript custom abstract method
    22
    abstract  class  CustomBase  extends  Script  {  
       def  run()  {  
           before()  
           internalRun()  
           after()  
       }  
    !
       abstract  internalRun()  
    !
       def  before()  {  println  'before'  }  
       def  after()    {  println  'after'    }  
    }
    

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67. @BaseScript custom abstract method
    22
    abstract  class  CustomBase  extends  Script  {  
       def  run()  {  
           before()  
           internalRun()  
           after()  
       }  
    !
       abstract  internalRun()  
    !
       def  before()  {  println  'before'  }  
       def  after()    {  println  'after'    }  
    }
    import  groovy.transform.BaseScript  
    @BaseScript  CustomBase  script  
    !
    println  'Hello'
    

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68. @BaseScript custom abstract method
    22
    abstract  class  CustomBase  extends  Script  {  
       def  run()  {  
           before()  
           internalRun()  
           after()  
       }  
    !
       abstract  internalRun()  
    !
       def  before()  {  println  'before'  }  
       def  after()    {  println  'after'    }  
    }
    import  groovy.transform.BaseScript  
    @BaseScript  CustomBase  script  
    !
    println  'Hello'
    You can define your own abstract
    method for script bodies
    

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69. @BaseScript custom abstract method
    22
    abstract  class  CustomBase  extends  Script  {  
       def  run()  {  
           before()  
           internalRun()  
           after()  
       }  
    !
       abstract  internalRun()  
    !
       def  before()  {  println  'before'  }  
       def  after()    {  println  'after'    }  
    }
    import  groovy.transform.BaseScript  
    @BaseScript  CustomBase  script  
    !
    println  'Hello'
    

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70. @glaforge — Groovy in 2014 and beyond
    NIO2 module
    

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71. JDK 7+ NIO2 module
    • All the familiar methods on File 

    retrofitted on Path as well
    24
    path.withReader  {  Reader  r  -­‐>  ...  }  
    path.eachLine  {  String  line  -­‐>  ...  }  
    path.eachFileRecurse  {  Path  p  -­‐>  ...  }  
    path  <<  'some  content'  
    path  <<  bytes  
    path.readLines()  
    …
    

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72. JDK 7+ NIO2 module
    • All the familiar methods on File 

    retrofitted on Path as well
    24
    path.withReader  {  Reader  r  -­‐>  ...  }  
    path.eachLine  {  String  line  -­‐>  ...  }  
    path.eachFileRecurse  {  Path  p  -­‐>  ...  }  
    path  <<  'some  content'  
    path  <<  bytes  
    path.readLines()  
    …
    Feature request to add all the
    java.nio.file.Files static utility
    methods as GDK
    

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73. JDK 7+ NIO2 module
    • All the familiar methods on File 

    retrofitted on Path as well
    24
    path.withReader  {  Reader  r  -­‐>  ...  }  
    path.eachLine  {  String  line  -­‐>  ...  }  
    path.eachFileRecurse  {  Path  p  -­‐>  ...  }  
    path  <<  'some  content'  
    path  <<  bytes  
    path.readLines()  
    …
    

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74. @glaforge — Groovy in 2014 and beyond
    JSON
    

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75. JSON parser / builder perf. increase
    • Re-implementation of JSON support for speed & efficiency
    
    • parser forked off the Boon JSON project
    
    • serializer carefully fine-tuned
    
    !
    • Article on the parsing speed improvements
    
    • http://rick-hightower.blogspot.fr/2014/04/groovy-and-boon-provide-fastest-json.html
    26
    

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76. JSON parser / builder perf. increase
    • Re-implementation of JSON support for speed & efficiency
    
    • parser forked off the Boon JSON project
    
    • serializer carefully fine-tuned
    
    !
    • Article on the parsing speed improvements
    
    • http://rick-hightower.blogspot.fr/2014/04/groovy-and-boon-provide-fastest-json.html
    26
    

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77. JSON parser / builder perf. increase
    • Re-implementation of JSON support for speed & efficiency
    
    • parser forked off the Boon JSON project
    
    • serializer carefully fine-tuned
    
    !
    • Article on the parsing speed improvements
    
    • http://rick-hightower.blogspot.fr/2014/04/groovy-and-boon-provide-fastest-json.html
    26
    Benchmark gives 3x to 4x
    performance factor 

    over Jackson and GSON
    

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78. JSON parser / builder perf. increase
    • Re-implementation of JSON support for speed & efficiency
    
    • parser forked off the Boon JSON project
    
    • serializer carefully fine-tuned
    
    !
    • Article on the parsing speed improvements
    
    • http://rick-hightower.blogspot.fr/2014/04/groovy-and-boon-provide-fastest-json.html
    26
    

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79. New modes for parsing
    • Original JsonSlurper renamed to JsonSlurperClassic
    
    !
    • Additional parsing modes:
    
    • INDEX_OVERLAY: super fast for <2MB payloads
    
    o using a « parsing overlay » technique
    
    • CHARACTER_SOURCE: for >2MB payloads
    
    o implemented with sliding windows over readers
    
    • LAX: beyond the JSON spec, nice for configuration files
    
    o support single quotes, / and # comments
    
    • CHAR_BUFFER: general purpose
    27
    

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80. JsonSlurper for configuration files
    28
    import  groovy.json.*  
    import  static  groovy.json.JsonParserType.*  
    !
    def  parser  =  new  JsonSlurper().setType(LAX)  
    !
    def  conf  =  parser.parseText  '''  
           //  configuration  file  
           {  
                   //  no  quote  for  key,  single  quoted  value  
                   environment:  'production'  
                   #  pound-­‐style  comment  
                   'server':  5  
           }  
    '''  
    !
    assert  conf.environment  ==  'production'  
    assert  conf.server  ==  5
    

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81. JsonSlurper for configuration files
    28
    import  groovy.json.*  
    import  static  groovy.json.JsonParserType.*  
    !
    def  parser  =  new  JsonSlurper().setType(LAX)  
    !
    def  conf  =  parser.parseText  '''  
           //  configuration  file  
           {  
                   //  no  quote  for  key,  single  quoted  value  
                   environment:  'production'  
                   #  pound-­‐style  comment  
                   'server':  5  
           }  
    '''  
    !
    assert  conf.environment  ==  'production'  
    assert  conf.server  ==  5
    More tolerant parser: 

    single quotes, 

    non-quoted keys, 

    // and # comments,
    missing comas
    

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82. JsonSlurper for configuration files
    28
    import  groovy.json.*  
    import  static  groovy.json.JsonParserType.*  
    !
    def  parser  =  new  JsonSlurper().setType(LAX)  
    !
    def  conf  =  parser.parseText  '''  
           //  configuration  file  
           {  
                   //  no  quote  for  key,  single  quoted  value  
                   environment:  'production'  
                   #  pound-­‐style  comment  
                   'server':  5  
           }  
    '''  
    !
    assert  conf.environment  ==  'production'  
    assert  conf.server  ==  5
    

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83. @glaforge — Groovy in 2014 and beyond
    Markup template engine
    >
    

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84. Markup template engine
    • Based on the principles of Groovy’s « builders »
    
    • and particularly the MarkupBuilder class

    for generating arbitrary XML / HTML payloads
    
    !
    • Compiled statically for fast template rendering
    !
    • Internationalization aware
    
    • provide the desired Locale in the configuration object
    
    • usual suffix notation template_fr_FR.tpl
    
    !
    • Custom base template class
    
    • ability to provide reusable methods across your templates 30
    

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85. Markup template engine
    • Based on the principles of Groovy’s « builders »
    
    • and particularly the MarkupBuilder class

    for generating arbitrary XML / HTML payloads
    
    !
    • Compiled statically for fast template rendering
    !
    • Internationalization aware
    
    • provide the desired Locale in the configuration object
    
    • usual suffix notation template_fr_FR.tpl
    
    !
    • Custom base template class
    
    • ability to provide reusable methods across your templates 30
    Spring Boot
    approved
    

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86. Markup template engine — the idea
    31
    cars  {  
         cars.each  {  
                 car(make:  it.make,  name:  it.name)  
         }  
    }
    

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87. Markup template engine — the idea
    31
    cars  {  
         cars.each  {  
                 car(make:  it.make,  name:  it.name)  
         }  
    }
    Your template
    

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88. Markup template engine — the idea
    31
    cars  {  
         cars.each  {  
                 car(make:  it.make,  name:  it.name)  
         }  
    }
    model = [cars: [!
    new Car(make: 'Peugeot', name: '508'), !
    new Car(make: 'Toyota', name: 'Prius’)!
    ]]
    

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89. Markup template engine — the idea
    31
    cars  {  
         cars.each  {  
                 car(make:  it.make,  name:  it.name)  
         }  
    }
    model = [cars: [!
    new Car(make: 'Peugeot', name: '508'), !
    new Car(make: 'Toyota', name: 'Prius’)!
    ]]
    Feed a model into
    your template
    

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90. Markup template engine — the idea
    31
    cars  {  
         cars.each  {  
                 car(make:  it.make,  name:  it.name)  
         }  
    }
    model = [cars: [!
    new Car(make: 'Peugeot', name: '508'), !
    new Car(make: 'Toyota', name: 'Prius’)!
    ]]
    !
    !
    !
    
    

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91. Markup template engine — the idea
    31
    cars  {  
         cars.each  {  
                 car(make:  it.make,  name:  it.name)  
         }  
    }
    model = [cars: [!
    new Car(make: 'Peugeot', name: '508'), !
    new Car(make: 'Toyota', name: 'Prius’)!
    ]]
    !
    !
    !
    
    Generate the
    XML output
    

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92. Markup template engine — the idea
    31
    cars  {  
         cars.each  {  
                 car(make:  it.make,  name:  it.name)  
         }  
    }
    model = [cars: [!
    new Car(make: 'Peugeot', name: '508'), !
    new Car(make: 'Toyota', name: 'Prius’)!
    ]]
    !
    !
    !
    
    

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93. Markup template engine — in action
    32
    import  groovy.text.markup.*  
    !
    def  config  =  new  TemplateConfiguration()  
    def  engine  =  new  MarkupTemplateEngine(config)  
    def  tmpl  =  engine.createTemplate('''  
           p("Hello  ${model.name}")  
    ''')  
    def  model  =  [name:  'World']  
    System.out  <<  tmpl.make(model)
    

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94. Markup template engine — includes
    33
    //  include  another  template  
    include  template:  'foo.tpl'  
           
    //  include  raw  content  
    include  unescaped:  'raw.txt'  
    !
    //  escape  &  include  
    include  escaped:  'to_escape.txt'
    

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95. Markup template engine — static!
    • Type-checked templates available
    
    • use createTypeCheckedModelTemplate() 

    instead of createTemplate()
    
    !
    • Advantages
    
    • get compilation errors
    
    o if a variable is not available
    
    o if you make mistakes in the code snippets
    
    • even faster templates
    34
    

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96. Markup template engine — static!
    • With typed check model
    creation method
    
    !
    !
    !
    !
    !
    !
    !
    !
    !
    • Or declare your model types
    in the template
    35
    

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97. Markup template engine — static!
    • With typed check model
    creation method
    
    !
    !
    !
    !
    !
    !
    !
    !
    !
    • Or declare your model types
    in the template
    35
    def  modelTypes  =  [cars:  "List"]  
    !
    def  tmpl  =  engine.  
       createTypeCheckedModelTemplate(

               "page.tpl",  modelTypes)
    

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98. Markup template engine — static!
    • With typed check model
    creation method
    
    !
    !
    !
    !
    !
    !
    !
    !
    !
    • Or declare your model types
    in the template
    35
    def  modelTypes  =  [cars:  "List"]  
    !
    def  tmpl  =  engine.  
       createTypeCheckedModelTemplate(

               "page.tpl",  modelTypes)
    modelTypes  =  {  
           List  cars  
    }  
    !
    cars.each  {  car  -­‐>  
           p("Car  name:  $car.name")  
    }
    

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99. Markup template engine — static!
    • With typed check model
    creation method
    
    !
    !
    !
    !
    !
    !
    !
    !
    !
    • Or declare your model types
    in the template
    35
    def  modelTypes  =  [cars:  "List"]  
    !
    def  tmpl  =  engine.  
       createTypeCheckedModelTemplate(

               "page.tpl",  modelTypes)
    modelTypes  =  {  
           List  cars  
    }  
    !
    cars.each  {  car  -­‐>  
           p("Car  name:  $car.name")  
    }
    Works with
    createTemplate() too
    

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100. Markup template engine — static!
     • With typed check model
     creation method
     
     !
     !
     !
     !
     !
     !
     !
     !
     !
     • Or declare your model types
     in the template
     35
     def  modelTypes  =  [cars:  "List"]  
     !
     def  tmpl  =  engine.  
        createTypeCheckedModelTemplate(

                "page.tpl",  modelTypes)
     modelTypes  =  {  
            List  cars  
     }  
     !
     cars.each  {  car  -­‐>  
            p("Car  name:  $car.name")  
     }
     

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101. @glaforge — Groovy in 2014 and beyond
     Documentation overhaul
     

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102. GroovyDoc
     37
     

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103. GroovyDoc
     37
     

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104. GroovyDoc
     37
     

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105. Groovy GDK documentation
     38
     

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106. Groovy GDK documentation
     38
     

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107. Brand new documentation
     39
     

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108. @glaforge — Groovy in 2014 and beyond
     Groovy 2.4
     

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109. Beta groovy-lang.org website
     41
     

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110. Beta groovy-lang.org website
     41
     

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111. Beta groovy-lang.org website
     41
     

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112. Beta groovy-lang.org website
     41
     Notice the « improve this
     doc » button!
     

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113. Android support
     • You can use Groovy to code Android apps!
     
     • use Groovy 2.4.0-beta-1+
     
     • prefer @CompileStatic
     
     !
     • Two great posts to get started:
     
     • http://melix.github.io/blog/2014/06/grooid.html
     
     • http://melix.github.io/blog/2014/06/grooid2.html
     42
     

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114. New York Times — Getting Groovy with Android
     • New York Times Getting Groovy with Reactive Android
     43
     

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115. New York Times — Getting Groovy with Android
     • New York Times Getting Groovy with Reactive Android
     43
     http://bit.ly/nyt-groovy
     

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116. Android support
     44
     

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117. Android support
     44
     Source code available:
     https://github.com/melix/gr8confagenda
     

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118. Groovy Macros
     !
     • Sergei Egorov wants to contribute a macro module
     
     • https://github.com/groovy/groovy-core/pull/470
     
     !
     • Simplify creation of AST transformations
     
     • less boilerplate manipulating the Groovy AST API
     
     • more powerful and less limited than AstBuilder
     45
     

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119. Groovy Macros
     !
     • Authoring AST transformations can be verbose:
     46
     def  someVariable  =  new  ConstantExpression("xyz")  
     def  returnStatement  =  new  ReturnStatement(  
            new  ConstructorCallExpression(  
                    ClassHelper.make(SomeCoolClass),  
                    new  ArgumentListExpression(someVariable)  
            )  
     )
     

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120. Groovy Macros
     • With Groovy Macros, it could be simpler:
     47
     def  someVariable  =  macro  {  "xyz"  }  
     def  returnStatement  =  macro  {    
            new  SomeCoolClass($v{  someVariable  })    
     }
     

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121. Groovy Macros
     • With Groovy Macros, it could be simpler:
     47
     def  someVariable  =  macro  {  "xyz"  }  
     def  returnStatement  =  macro  {    
            new  SomeCoolClass($v{  someVariable  })    
     }
     Special « macro » command
     

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122. Groovy Macros
     • With Groovy Macros, it could be simpler:
     47
     def  someVariable  =  macro  {  "xyz"  }  
     def  returnStatement  =  macro  {    
            new  SomeCoolClass($v{  someVariable  })    
     }
     Special « macro » command
     Quasi-quotation
     

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123. @glaforge — Groovy in 2014 and beyond
     Groovy 3.0
     

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124. View Slide

125. @glaforge — Groovy in 2014 and beyond
     New Age
     Meta-Object Protocol
     MOP 2
     

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126. Goals for the new MOP
     • Leverage & build upon JDK 7+ invoke dynamic
     
     • get Java-like performance even for dynamic code
     
     • Rationalize the sedimentation of meta-programming
     
     • more coherence, less corner cases & inconsistencies
     
     • Provide a notion of « realm »
     
     • shield users of « monkey patching »
     
     • finer-grained control of meta-programming reach
     
     • Private visibility anyone?
     51
     

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127. @glaforge — Groovy in 2014 and beyond
     Rewriting the
     Groovy grammar
     with Antlr v4
     Antlr v4 Grammar
     

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128. Antlr v4 grammar
     • Problems
     • Groovy still uses Antlr v2!
     
     o but version 3 and 4 are out
     
     • Groovy’s grammar evolved from a Java grammar
     
     o harder to fix and evolve, especially with Antlr v2
     
     • Advantages
     • Start from a clean slate
     
     • Antlr 4 more tolerant 

     and powerful regarding ambiguities
     
     • Time to clean some grammar & syntax warts!
     
     • Need to implement the Java 8 constructs!
     53
     

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129. Antlr v4 grammar
     • Problems
     • Groovy still uses Antlr v2!
     
     o but version 3 and 4 are out
     
     • Groovy’s grammar evolved from a Java grammar
     
     o harder to fix and evolve, especially with Antlr v2
     
     • Advantages
     • Start from a clean slate
     
     • Antlr 4 more tolerant 

     and powerful regarding ambiguities
     
     • Time to clean some grammar & syntax warts!
     
     • Need to implement the Java 8 constructs!
     53
     A « Google Summer of Code »
     student helped kick start it
     

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130. @glaforge — Groovy in 2014 and beyond
     Support the
     new Java 8
     language features
     Java 8 language support
     

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131. Java 8 support
     • Additional grammar & semantic features to support
     
     • to keep saying Groovy / Java interoperability is awesome!
     
     • New in Java 8
     
     • lambdas
     
     • method references
     
     • default methods in interfaces
     
     • stream API, date / time API
     
     • annotations on types & repeated annotations
     55
     

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132. Java 8 support
     • Additional grammar & semantic features to support
     
     • to keep saying Groovy / Java interoperability is awesome!
     
     • New in Java 8
     
     • lambdas
     
     • method references
     
     • default methods in interfaces
     
     • stream API, date / time API
     
     • annotations on types & repeated annotations
     55
     Groovy had already:
     closures, method pointers, mixins,
     enriched collection & time APIs
     

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133. @glaforge — Groovy in 2014 and beyond
     Summary
     

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134. View Slide

135. Groovy rocks the JVM 

     since 2003!
     

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136. @glaforge — Groovy in 2014 and beyond
     Q & A
     

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137. View Slide

138. Image credits
     • Big rock
     • http://wallpaper.preview-reviews.com/12852-red-rocks-in-a-snowstorm
     
     • Android robot
     • http://crackberry.com/sites/crackberry.com/files/styles/large/public/topic_images/2013/ANDROID.png?itok=xhm7jaxS
     
     • Modern MOP
     • http://i933.photobucket.com/albums/ad179/autobin/Wonder%20Mop/wondermop4.jpg
     
     • Jason
     • http://static.comicvine.com/uploads/original/3/32405/1031312-jason_19_inch_figure_l.jpg
     
     • Jigsaw
     • http://www.psdgraphics.com/file/psd-jigsaw-icon.jpg
     
     • Many thanks
     • http://www.trys.ie/wp-content/uploads/2013/06/many-thanks.jpg
     60
     

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