Guillaume Laforge, profile picture
Uploaded byGuillaume Laforge
PDF, PPTX1,083 views

Groovy 2.0 update - Cloud Foundry Open Tour Moscow - Guillaume Laforge

The document discusses new features in Groovy 1.8 and upcoming changes in Groovy 2.0. Key points include: - Groovy 1.8 introduced "command chains" allowing method calls to be written without dots or parentheses for improved readability. - Other Groovy 1.8 features included performance improvements, GPars for concurrency, and built-in JSON support. - Groovy 2.0 will align more with JDK 7, add static type checking and compilation, and improve modularity.

Embed presentation

Download as PDF, PPTX
1 / 116
2 / 116
3 / 116
4 / 116
5 / 116
6 / 116
7 / 116
8 / 116
9 / 116
10 / 116
11 / 116
12 / 116
13 / 116
14 / 116
15 / 116
16 / 116
17 / 116
18 / 116
19 / 116
20 / 116
21 / 116
22 / 116
23 / 116
24 / 116
25 / 116
26 / 116
27 / 116
28 / 116
29 / 116
30 / 116
31 / 116
32 / 116
33 / 116
34 / 116
35 / 116
36 / 116
37 / 116
38 / 116
39 / 116
40 / 116
41 / 116
42 / 116
43 / 116
44 / 116
45 / 116
46 / 116
47 / 116
48 / 116
49 / 116
50 / 116
51 / 116
52 / 116
53 / 116
54 / 116
55 / 116
56 / 116
57 / 116
58 / 116
59 / 116
60 / 116
61 / 116
62 / 116
63 / 116
64 / 116
65 / 116
66 / 116
67 / 116
68 / 116
69 / 116
70 / 116
71 / 116
72 / 116
73 / 116
74 / 116
75 / 116
76 / 116
77 / 116
78 / 116
79 / 116
80 / 116
81 / 116
82 / 116
83 / 116
84 / 116
85 / 116
86 / 116
87 / 116
88 / 116
89 / 116
90 / 116
91 / 116
92 / 116
93 / 116
94 / 116
95 / 116
96 / 116
97 / 116
98 / 116
99 / 116
100 / 116
101 / 116
102 / 116
103 / 116
104 / 116
105 / 116
106 / 116
107 / 116
108 / 116
109 / 116
110 / 116
111 / 116
112 / 116
113 / 116
114 / 116
115 / 116
116 / 116
Groovy 2.0 What’s up, Doc? Guillaume Laforge Groovy Project Manager SpringSource / VMware @glaforge 1
Groovy 2.0 What’s up, Doc? Guillaume Laforge Groovy Project Manager SpringSource / VMware @glaforge 1
Guillaume Laforge • Groovy Project Manager at VMware •Initiator of the Grails framework •Creator of the Gaelyk and Caelyf toolkits • Co-author of Groovy in Action • Follow me on... •My blog: http://glaforge.appspot.com •Twitter: @glaforge •Google+: http://gplus.to/glaforge 2
Agenda (1/2) • What’s new in Groovy 1.8? • Nicer DSLs with command chains • Runtime performance improvements • GPars bundled for taming your multicores • Closure enhancements • Builtin JSON support • New AST transformations 3
Agenda (2/2) • What’s cooking for Groovy 2.0? • Alignments with JDK 7 • Project Coin (small language changes) • Invoke Dynamic support • Continued runtime performance improvements • Static type checking • Static compilation • Modularity 4
Command chains • A grammar improvement allowing you to drop dots & parens when chaining method calls • an extended version of top-level statements like println • Less dots, less parens allow you to •write more readable business rules •in almost plain English sentences • (or any language, of course) 5
Command chains  turn  left    then  right   6
Command chains Alternation of method names  turn  left    then  right   6
Command chains Alternation of method names  turn  left    then  right   and parameters (even named ones) 6
Command chains  turn  left    then  right   6
Command chains Equivalent to:          (        ).        (          )  turn  left    then  right   6
Look Ma! No par ens, no dots!
Command chains take  2    pills  of    chloroquinine    after    6  hours 8
Command chains        (  ).          (    ).                            (          ).  (          ) take  2    pills  of    chloroquinine    after    6  hours 8
Command chains 9
Command chains //  methods  with  multiple  arguments  (commas) 9
Command chains //  methods  with  multiple  arguments  (commas) take  coffee    with  sugar,  milk    and  liquor 9
Command chains //  methods  with  multiple  arguments  (commas) take  coffee    with  sugar,  milk    and  liquor //  leverage  named-­‐args  as  punctuation 9
Command chains //  methods  with  multiple  arguments  (commas) take  coffee    with  sugar,  milk    and  liquor //  leverage  named-­‐args  as  punctuation check  that:  margarita    tastes  good 9
Command chains //  methods  with  multiple  arguments  (commas) take  coffee    with  sugar,  milk    and  liquor //  leverage  named-­‐args  as  punctuation check  that:  margarita    tastes  good //  closure  parameters  for  new  control  structures 9
Command chains //  methods  with  multiple  arguments  (commas) take  coffee    with  sugar,  milk    and  liquor //  leverage  named-­‐args  as  punctuation check  that:  margarita    tastes  good //  closure  parameters  for  new  control  structures given  {}    when  {}    then  {} 9
Command chains //  methods  with  multiple  arguments  (commas) take  coffee    with  sugar,  milk    and  liquor //  leverage  named-­‐args  as  punctuation check  that:  margarita    tastes  good //  closure  parameters  for  new  control  structures given  {}    when  {}    then  {} //  zero-­‐arg  methods  require  parens 9
Command chains //  methods  with  multiple  arguments  (commas) take  coffee    with  sugar,  milk    and  liquor //  leverage  named-­‐args  as  punctuation check  that:  margarita    tastes  good //  closure  parameters  for  new  control  structures given  {}    when  {}    then  {} //  zero-­‐arg  methods  require  parens select  all    unique()  from  names 9
Command chains //  methods  with  multiple  arguments  (commas) take  coffee    with  sugar,  milk    and  liquor //  leverage  named-­‐args  as  punctuation check  that:  margarita    tastes  good //  closure  parameters  for  new  control  structures given  {}    when  {}    then  {} //  zero-­‐arg  methods  require  parens select  all    unique()  from  names //  possible  with  an  odd  number  of  terms 9
Command chains //  methods  with  multiple  arguments  (commas) take  coffee    with  sugar,  milk    and  liquor //  leverage  named-­‐args  as  punctuation check  that:  margarita    tastes  good //  closure  parameters  for  new  control  structures given  {}    when  {}    then  {} //  zero-­‐arg  methods  require  parens select  all    unique()  from  names //  possible  with  an  odd  number  of  terms take  3    cookies 9
Command chains //  methods  with  multiple  arguments  (commas) take  coffee    with  sugar,  milk    and  liquor        (            ).        (                      ).      (            ) //  leverage  named-­‐args  as  punctuation check  that:  margarita    tastes  good //  closure  parameters  for  new  control  structures given  {}    when  {}    then  {} //  zero-­‐arg  methods  require  parens select  all    unique()  from  names //  possible  with  an  odd  number  of  terms take  3    cookies 9
Command chains //  methods  with  multiple  arguments  (commas) take  coffee    with  sugar,  milk    and  liquor        (            ).        (                      ).      (            ) //  leverage  named-­‐args  as  punctuation check  that:  margarita    tastes  good          (                              ).            (        ) //  closure  parameters  for  new  control  structures given  {}    when  {}    then  {} //  zero-­‐arg  methods  require  parens select  all    unique()  from  names //  possible  with  an  odd  number  of  terms take  3    cookies 9
Command chains //  methods  with  multiple  arguments  (commas) take  coffee    with  sugar,  milk    and  liquor        (            ).        (                      ).      (            ) //  leverage  named-­‐args  as  punctuation check  that:  margarita    tastes  good          (                              ).            (        ) //  closure  parameters  for  new  control  structures given  {}    when  {}    then  {}          (    ).        (    ).        (    ) //  zero-­‐arg  methods  require  parens select  all    unique()  from  names //  possible  with  an  odd  number  of  terms take  3    cookies 9
Command chains //  methods  with  multiple  arguments  (commas) take  coffee    with  sugar,  milk    and  liquor        (            ).        (                      ).      (            ) //  leverage  named-­‐args  as  punctuation check  that:  margarita    tastes  good          (                              ).            (        ) //  closure  parameters  for  new  control  structures given  {}    when  {}    then  {}          (    ).        (    ).        (    ) //  zero-­‐arg  methods  require  parens select  all    unique()  from  names            (      ).                .        (          ) //  possible  with  an  odd  number  of  terms take  3    cookies 9
Command chains //  methods  with  multiple  arguments  (commas) take  coffee    with  sugar,  milk    and  liquor        (            ).        (                      ).      (            ) //  leverage  named-­‐args  as  punctuation check  that:  margarita    tastes  good          (                              ).            (        ) //  closure  parameters  for  new  control  structures given  {}    when  {}    then  {}          (    ).        (    ).        (    ) //  zero-­‐arg  methods  require  parens select  all    unique()  from  names            (      ).                .        (          ) //  possible  with  an  odd  number  of  terms take  3    cookies        (  ). 9
GPars bundled • GPars is bundled in the Groovy distribution • GPars covers a wide range of parallel and concurrent paradigms • actors, fork/join, map/filter/reduce, dataflow, agents • parallel arrays, executors, STM, and more... • And you can use it from plain Java as well! 10
Closure enhancements • Closure annotation parameters • Some more functional flavor •composition: compose several closures into one single closure •trampoline: avoid stack overflow errors for recursive algorithms •memoization: remember the outcome of previous closure invocations •currying improvements 11
Closure annotation parameters @Retention(RetentionPolicy.RUNTIME) @interface  Invariant  {                Class  value()  //  a  closure  class }   { @Invariant({  number  >=  0  }) class  Distance  {                float  number                String  unit }     def  d  =  new  Distance(number:  10,  unit:  "meters")   def  anno  =  Distance.getAnnotation(Invariant) def  check  =  anno.value().newInstance(d,  d) assert  check(d) 12
Closure annotation parameters @Retention(RetentionPolicy.RUNTIME) @interface  Invariant  {                Class  value()  //  a  closure  class }   { @Invariant({  number  >=  0  }) class  Distance  {                float  number         Poor -man ’s G Cont racts        String  unit }     def  d  =  new  Distance(number:  10,  unit:  "meters")   def  anno  =  Distance.getAnnotation(Invariant) def  check  =  anno.value().newInstance(d,  d) assert  check(d) 12
Closure memoization 13
Closure memoization def  plus  =  {  a,  b  -­‐>  sleep  1000;  a  +  b  }.memoize() 13
Closure memoization def  plus  =  {  a,  b  -­‐>  sleep  1000;  a  +  b  }.memoize() assert  plus(1,  2)  ==  3  //  after  1000ms 13
Closure memoization def  plus  =  {  a,  b  -­‐>  sleep  1000;  a  +  b  }.memoize() assert  plus(1,  2)  ==  3  //  after  1000ms assert  plus(1,  2)  ==  3  //  return  immediately 13
Closure memoization def  plus  =  {  a,  b  -­‐>  sleep  1000;  a  +  b  }.memoize() assert  plus(1,  2)  ==  3  //  after  1000ms assert  plus(1,  2)  ==  3  //  return  immediately assert  plus(2,  2)  ==  4  //  after  1000ms 13
Closure memoization def  plus  =  {  a,  b  -­‐>  sleep  1000;  a  +  b  }.memoize() assert  plus(1,  2)  ==  3  //  after  1000ms assert  plus(1,  2)  ==  3  //  return  immediately assert  plus(2,  2)  ==  4  //  after  1000ms assert  plus(2,  2)  ==  4  //  return  immediately     13
Closure memoization def  plus  =  {  a,  b  -­‐>  sleep  1000;  a  +  b  }.memoize() assert  plus(1,  2)  ==  3  //  after  1000ms assert  plus(1,  2)  ==  3  //  return  immediately assert  plus(2,  2)  ==  4  //  after  1000ms assert  plus(2,  2)  ==  4  //  return  immediately       13
Closure memoization def  plus  =  {  a,  b  -­‐>  sleep  1000;  a  +  b  }.memoize() assert  plus(1,  2)  ==  3  //  after  1000ms assert  plus(1,  2)  ==  3  //  return  immediately assert  plus(2,  2)  ==  4  //  after  1000ms assert  plus(2,  2)  ==  4  //  return  immediately       //  at  least  10  invocations  cached 13
Closure memoization def  plus  =  {  a,  b  -­‐>  sleep  1000;  a  +  b  }.memoize() assert  plus(1,  2)  ==  3  //  after  1000ms assert  plus(1,  2)  ==  3  //  return  immediately assert  plus(2,  2)  ==  4  //  after  1000ms assert  plus(2,  2)  ==  4  //  return  immediately       //  at  least  10  invocations  cached def  plusAtLeast  =  {  ...  }.memoizeAtLeast(10) 13
Closure memoization def  plus  =  {  a,  b  -­‐>  sleep  1000;  a  +  b  }.memoize() assert  plus(1,  2)  ==  3  //  after  1000ms assert  plus(1,  2)  ==  3  //  return  immediately assert  plus(2,  2)  ==  4  //  after  1000ms assert  plus(2,  2)  ==  4  //  return  immediately       //  at  least  10  invocations  cached def  plusAtLeast  =  {  ...  }.memoizeAtLeast(10)   13
Closure memoization def  plus  =  {  a,  b  -­‐>  sleep  1000;  a  +  b  }.memoize() assert  plus(1,  2)  ==  3  //  after  1000ms assert  plus(1,  2)  ==  3  //  return  immediately assert  plus(2,  2)  ==  4  //  after  1000ms assert  plus(2,  2)  ==  4  //  return  immediately       //  at  least  10  invocations  cached def  plusAtLeast  =  {  ...  }.memoizeAtLeast(10)   //  at  most  10  invocations  cached 13
Closure memoization def  plus  =  {  a,  b  -­‐>  sleep  1000;  a  +  b  }.memoize() assert  plus(1,  2)  ==  3  //  after  1000ms assert  plus(1,  2)  ==  3  //  return  immediately assert  plus(2,  2)  ==  4  //  after  1000ms assert  plus(2,  2)  ==  4  //  return  immediately       //  at  least  10  invocations  cached def  plusAtLeast  =  {  ...  }.memoizeAtLeast(10)   //  at  most  10  invocations  cached def  plusAtMost  =  {  ...  }.memoizeAtMost(10)   13
Closure memoization def  plus  =  {  a,  b  -­‐>  sleep  1000;  a  +  b  }.memoize() assert  plus(1,  2)  ==  3  //  after  1000ms assert  plus(1,  2)  ==  3  //  return  immediately assert  plus(2,  2)  ==  4  //  after  1000ms assert  plus(2,  2)  ==  4  //  return  immediately       //  at  least  10  invocations  cached def  plusAtLeast  =  {  ...  }.memoizeAtLeast(10)   //  at  most  10  invocations  cached def  plusAtMost  =  {  ...  }.memoizeAtMost(10)   //  between  10  and  20  invocations  cached 13
Closure memoization def  plus  =  {  a,  b  -­‐>  sleep  1000;  a  +  b  }.memoize() assert  plus(1,  2)  ==  3  //  after  1000ms assert  plus(1,  2)  ==  3  //  return  immediately assert  plus(2,  2)  ==  4  //  after  1000ms assert  plus(2,  2)  ==  4  //  return  immediately       //  at  least  10  invocations  cached def  plusAtLeast  =  {  ...  }.memoizeAtLeast(10)   //  at  most  10  invocations  cached def  plusAtMost  =  {  ...  }.memoizeAtMost(10)   //  between  10  and  20  invocations  cached def  plusAtLeast  =  {  ...  }.memoizeBetween(10,  20) 13
Builtin JSON support • Consuming • Producing • Pretty-printing 14
Builtin JSON support import  groovy.json.*   def  payload  =  new  URL(        "http://github.../json/commits/...").text   def  slurper  =  new  JsonSlurper() def  doc  =  slurper.parseText(payload)   doc.commits.message.each  {  println  it  } 15
Builtin JSON support import  groovy.json.*     def  json  =  new  JsonBuilder()     json.person  {                name  "Guillaume"        age  34                pets  "Hector",  "Felix" }   println  json.toString() 16
Builtin JSON support import  groovy.json.*     def  json  =  new  JsonBuilder()     {         json.person  {                "person":  {                        name  "Guillaume"                "name":  "Guillaume",              age  34                        "age":  34,                                "pets":  [                                pets  "Hector",  "Felix"                        "Hector",                     }                          "Felix"                 println  json.toString()                ]                } } 16
Builtin JSON support import  groovy.json.*     println  JsonOutput.prettyPrint(        '''{"person":{"name":"Guillaume","age":34,'''  +          '''"pets":["Hector","Felix"]}}''')   {                "person":  {                                "name":  "Guillaume",                    "age":  34,                                "pets":  [                                                "Hector",                                          "Felix"                                ]                } } 17
New AST transformations • @Log • Controlling execution • @ThreadInterrupt • @Field • @TimedInterrupt • @ConditionalInterrupt • @AutoClone • @InheritConstructor • @AutoExternalizable • @WithReadLock • @Canonical • @WithWriteLock • @ToString • @EqualsAndHashCode • @TupleConstructor • @ListenerList 18
@Log • Four different loggers can be injected import  groovy.util.logging.*   •@Log   •@Commons @Log class  Car  {         •@Log4j        Car()  {                 •@Slf4j                log.info  'Car  built'                } }     • Possible to implement def  c  =  new  Car() your own strategy 19
@Log • Four different loggers can be injected import  groovy.util.logging.*   •@Log   •@Commons @Log class  Car  {         •@Log4j        Car()  {                 •@Slf4j Guarded w/ an if                log.info  'Car  built'                } }     • Possible to implement def  c  =  new  Car() your own strategy 19
Controlling code execution • Your application may run user’s code •what if the code runs in infinite loops or for too long? •what if the code consumes too many resources? • 3 new transforms at your rescue • @ThreadInterrupt: adds Thread#isInterrupted checks so your executing thread stops when interrupted • @TimedInterrupt: adds checks in method and closure bodies to verify it’s run longer than expected • @ConditionalInterrupt: adds checks with your own conditional logic to break out from the user code 20
@ThreadInterrupt @ThreadInterrupt import  groovy.transform.ThreadInterrupt     while  (true)  {        //  eat  lots  of  CPU } 21 33
@ThreadInterrupt @ThreadInterrupt import  groovy.transform.ThreadInterrupt     while  (true)  { {        if  (Thread.currentThread.isInterrupted())                throw  new  InterruptedException() }        //  eat  lots  of  CPU } 21 33
@ToString • Provides a default toString() method to your types • Available annotation options • includeNames, includeFields, includeSuper, excludes import  groovy.transform.ToString     @ToString class  Person  {                String  name                int  age }     println  new  Person(name:  'Pete',  age:  15) //  =>  Person(Pete,  15) 22
@EqualsAndHashCode • Provides default implementations for equals() and hashCode() methods import  groovy.transform.EqualsAndHashCode     @EqualsAndHashCode class  Coord  {                int  x,  y }     def  c1  =  new  Coord(x:  20,  y:  5) def  c2  =  new  Coord(x:  20,  y:  5)     assert  c1  ==  c2 assert  c1.hashCode()  ==  c2.hashCode() 23
@TupleConstructor • Provides a «classical» constructor with all properties • Several annotation parameter options available import  groovy.transform.TupleConstructor     @TupleConstructor   class  Person  {                String  name                int  age }     def  m  =  new  Person('Marion',  4)               assert  m.name  ==  'Marion' assert  m.age    ==  4 24
@InheritConstructors • Classes like Exception are painful when extended, as all the base constructors should be replicated class  CustomException  extends  Exception  {        CustomException()                                                {  super()              }        CustomException(String  msg)                            {  super(msg)        }        CustomException(String  msg,  Throwable  t)  {  super(msg,  t)  }        CustomException(Throwable  t)                          {  super(t)            } } 25
@InheritConstructors • Classes like Exception are painful when extended, as all the base constructors should be replicated import  groovy.transform.* @InheritConstructors class  CustomException  extends  Exception  {        CustomException()                                                {  super()              }        CustomException(String  msg)                            {  super(msg)        }        CustomException(String  msg,  Throwable  t)  {  super(msg,  t)  }        CustomException(Throwable  t)                          {  super(t)            } } 25
Miscelanous • Compilation customizers • Java 7 diamond operator • Slashy and dollar slashy strings • New GDK methods • (G)String to Enum coercion • Customizing the Groovysh prompt • Executing remote scripts 26
Compilation customizers • Ability to apply some customization to the Groovy compilation process • Three available customizers •ImportCustomizer •ASTTransformationCustomizer •SecureASTCustomizer • But you can implement your own 27
Imports customizer def  configuration  =  new  CompilerConfiguration()   def  custo  =  new  ImportCustomizer() custo.addStaticStar(Math.name) configuration.addCompilationCustomizers(custo)     def  result  =  new  GroovyShell(configuration)                          //  import  static  java.lang.Math.*        .evaluate("  cos  PI/3  ")                             28
What’s cooking for 2.0?
Groovy 2.0 roadmap • Towards a more modular Groovy • Java 7 alignements: Project Coin • binary literals • underscore in literals • multicatch • JDK 7: InvokeDynamic • Static type checking • Static compilation 30
Groovy Modularity • Groovy’s «all» JAR weighs in at 4MB • Nobody needs everything • Template engine, Ant scripting, Swing UI building... • Provide a smaller core • and several smaller JARs per feature • Provide hooks for setting up DGM methods, etc. 31
Java 7 / JDK 7 • Project Coin and InvokeDynamic 32
Binary literals • We had decimal, octal and hexadecimal notations for number literals • We can now use binary representations too int  x  =  0b10101111 assert  x  ==  175   byte  aByte  =  0b00100001 assert  aByte  ==  33   int  anInt  =  0b1010000101000101 assert  anInt  ==  41285 33
Underscore in literals • Now we can also add underscores in number literals for more readability long  creditCardNumber  =  1234_5678_9012_3456L long  socialSecurityNumbers  =  999_99_9999L float  monetaryAmount  =  12_345_132.12 long  hexBytes  =  0xFF_EC_DE_5E long  hexWords  =  0xFFEC_DE5E long  maxLong  =  0x7fff_ffff_ffff_ffffL long  alsoMaxLong  =  9_223_372_036_854_775_807L long  bytes  =  0b11010010_01101001_10010100_10010010 34
Multicatch • One block for multiple exception caught •rather than duplicating the block try  {        /*  ...  */ }  catch(IOException  |  NullPointerException  e)  {        /*  one  block  to  treat  2  exceptions  */ } 35
InvokeDynamic • Groovy 2.0 supports JDK 7’s invokeDynamic • compiler has a flag for compiling against JDK 7 • might use the invokeDynamic backport for < JDK 7 • Benefits • more runtime performance! • at least as fast as current «dynamic» Groovy •in the long run, will allow us to get rid of code! • call site caching, thanks to MethodHandles • metaclass registry, thanks to ClassValues • will let the JIT inline calls more easily 36
Static Type Checking • Goal: make the Groovy compiler «grumpy»! • and throw compilation errors (not at runtime) • Not everybody needs dynamic features all the time • think Java libraries scripting • Grumpy should... • tell you about your method or variable typos • complain if you call methods that don’t exist • shout on assignments of wrong types • infer the types of your variables • figure out GDK methods • etc... 37
Typos in your vars or methods import  groovy.transform.TypeChecked   void  method()  {}   @TypeChecked  test()  {        //  Cannot  find  matching  method  metthhoood()        metthhoood()          def  name  =  "Guillaume"        //  variable  naamme  is  undeclared        println  naamme } 38
Typos in your vars or methods import  groovy.transform.TypeChecked   void  method()  {}   @TypeChecked  test()  {        //  Cannot  find  matching  method  metthhoood()        metthhoood()   Compilation        def  name  =  "Guillaume" errors!        //  variable  naamme  is  undeclared        println  naamme } 38
Typos in your vars or methods import  groovy.transform.TypeChecked Annotation can be at   class or method level void  method()  {}   @TypeChecked  test()  {        //  Cannot  find  matching  method  metthhoood()        metthhoood()   Compilation        def  name  =  "Guillaume" errors!        //  variable  naamme  is  undeclared        println  naamme } 38
Complain on wrong assignments //  cannot  assign  value  of  type...  to  variable... int  x  =  new  Object() Set  set  =  new  Object()   def  o  =  new  Object() int  x  =  o   String[]  strings  =  ['a','b','c'] int  str  =  strings[0]   //  cannot  find  matching  method  plus() int  i  =  0 i  +=  '1' 39
Complain on wrong assignments //  cannot  assign  value  of  type...  to  variable... int  x  =  new  Object() Set  set  =  new  Object() Compilation   errors! def  o  =  new  Object() int  x  =  o   String[]  strings  =  ['a','b','c'] int  str  =  strings[0]   //  cannot  find  matching  method  plus() int  i  =  0 i  +=  '1' 39
Complain on wrong return types //  checks  if/else  branch  return  values @TypeChecked int  method()  {        if  (true)  {  'String'  }        else  {  42  } } //  works  for  switch/case  &  try/catch/finally   //  transparent  toString()  implied @TypeChecked String  greeting(String  name)  {        def  sb  =  new  StringBuilder()        sb  <<  "Hi  "  <<  name } 40
Complain on wrong return types //  checks  if/else  branch  return  values @TypeChecked int  method()  { Compilation        if  (true)  {  'String'  } error!        else  {  42  } } //  works  for  switch/case  &  try/catch/finally   //  transparent  toString()  implied @TypeChecked String  greeting(String  name)  {        def  sb  =  new  StringBuilder()        sb  <<  "Hi  "  <<  name } 40
Type inference @TypeChecked  test()  {        def  name  =  "    Guillaume    "          //  String  type  infered  (even  inside  GString)        println  "NAME  =  ${name.toUpperCase()}"            //  Groovy  GDK  method  support        //  (GDK  operator  overloading  too)        println  name.trim()          int[]  numbers  =  [1,  2,  3]        //  Element  n  is  an  int        for  (int  n  in  numbers)  {                println  n        } } 41
Statically checked & dynamic methods @TypeChecked String  greeting(String  name)  {        //  call  method  with  dynamic  behavior        //  but  with  proper  signature        generateMarkup(name.toUpperCase()) }   //  usual  dynamic  behavior String  generateMarkup(String  name)  {        def  sw  =  new  StringWriter()        new  MarkupBuilder(sw).html  {                body  {                        div  name                }        }        sw.toString() } 42
Instanceof checks @TypeChecked   void  test(Object  val)  {        if  (val  instanceof  String)  {                println  val.toUpperCase()        }  else  if  (val  instanceof  Number)  {                println  "X"  *  val.intValue()        } } 43
Instanceof checks @TypeChecked   No need void  test(Object  val)  { for casts        if  (val  instanceof  String)  {                println  val.toUpperCase()        }  else  if  (val  instanceof  Number)  {                println  "X"  *  val.intValue()        } } 43
Instanceof checks @TypeChecked   No need void  test(Object  val)  { for casts        if  (val  instanceof  String)  {                println  val.toUpperCase()        }  else  if  (val  instanceof  Number)  {                println  "X"  *  val.intValue()        } } Can call String#multiply(int) from the Groovy Development Kit 43
Lowest Upper Bound • Represents the lowest «super» type that classes have in common •may be virtual (aka «non-denotable») @TypeChecked  test()  {        //  an  integer  and  a  BigDecimal        return  [1234,  3.14] } 44
Lowest Upper Bound • Represents the lowest «super» type that classes have in common •may be virtual (aka «non-denotable») @TypeChecked  test()  {        //  an  integer  and  a  BigDecimal        return  [1234,  3.14] } Inferred return type: List<Number> 44
Flow typing • Static type checking shouldn’t complain even for bad coding practicies which work without type checks @TypeChecked  test()  {        def  var  =  123                  //  inferred  type  is  int        int  x  =  var                      //  var  is  an  int        var  =  "123"                      //  assign  var  with  a  String        x  =  var.toInteger()      //  no  problem,  no  need  to  cast        var  =  123        x  =  var.toUpperCase()  //  error,  var  is  int! } 45
Gotchas: static checking vs dynamic • Type checking works at compile-time • adding @TypeChecked doesn’t change behavior • do not confuse with static compilation • Most dynamic features cannot be type checked •metaclass changes, categories •dynamically bound variables (ex: script’s binding) • However, compile-time metaprogramming works •as long as proper type information is defined 46
Gotchas: runtime metaprogramming @TypeChecked   void  test()  {        Integer.metaClass.foo  =  {}        123.foo() } 47
Gotchas: runtime metaprogramming @TypeChecked   void  test()  {        Integer.metaClass.foo  =  {}        123.foo() } Not allowed: metaClass property is dynamic 47
Gotchas: runtime metaprogramming @TypeChecked   void  test()  {        Integer.metaClass.foo  =  {}        123.foo() } Method not Not allowed: recognized metaClass property is dynamic 47
Gotchas: closures need explicit types @TypeChecked  test()  {        ["a",  "b",  "c"].collect  {                it.toUpperCase()  //  Not  OK        } } • A «Groovy Enhancement Proposal» to address this issue 48
Gotchas: closures need explicit types @TypeChecked  test()  {        ["a",  "b",  "c"].collect  {  String  it  -­‐>                it.toUpperCase()  //  OK,  it’s  a  String        } } • A «Groovy Enhancement Proposal» to address this issue 48
Closure shared variables @TypeChecked  test()  {        def  var  =  "abc"                      def  cl  =  {  var  =  new  Date()  }        cl()        var.toUpperCase()    //  Not  OK! } 49
Closure shared variables var assigned in the closure: «shared closure variable» @TypeChecked  test()  {        def  var  =  "abc"                      def  cl  =  {  var  =  new  Date()  }        cl()        var.toUpperCase()    //  Not  OK! } 49
Closure shared variables var assigned in the closure: «shared closure variable» @TypeChecked  test()  { Impossible to        def  var  =  "abc"               ensure        def  cl  =  {  var  =  new  Date()  } the assignment        cl() really happens        var.toUpperCase()    //  Not  OK! } 49
Closure shared variables var assigned in the closure: «shared closure variable» @TypeChecked  test()  { Impossible to        def  var  =  "abc"               ensure        def  cl  =  {  var  =  new  Date()  } the assignment        cl() really happens        var.toUpperCase()    //  Not  OK! } Only methods of the most specific compatible type (LUB) are allowed by the type checker 49
Closure shared variables class  A                      {  void  foo()  {}  } class  B  extends  A  {  void  bar()  {}  } @TypeChecked  test()  {        def  var  =  new  A()        def  cl  =  {  var  =  new  B()  }        cl()        var.foo()      //  OK! } 50
Closure shared variables class  A                      {  void  foo()  {}  } class  B  extends  A  {  void  bar()  {}  } @TypeChecked  test()  {        def  var  =  new  A()        def  cl  =  {  var  =  new  B()  }        cl()        var.foo()      //  OK! } var is at least an instance of A 50
Static Compilation • Given your Groovy code can be type checked... we can as well compile it «statically» • ie. generate the same byte code as javac • Also interesting for those stuck in JDK < 7 to benefit from performance improvements 51
Static Compilation: advantages • You gain: • Type safety • thanks to static type checking • static compilation builds upon static type checking • Faster code • as close as possible to Java’s performance • Code immune to «monkey patching» • metaprogramming badly used can interfere with framework code • Smaller bytecode size 52
Static Compilation: advantages • You gain: • Type safety • thanks to static type checking • static compilation builds upon static type checking • Faster code • as close as possible to Java’s performance • Code immune to «monkey patching» • metaprogramming badly used can interfere with framework code • Smaller bytecode size 52
Static Compilation: disadvantages • But you loose: • Dynamic features •metaclass changes, categories, etc. • Dynamic method dispatch •although as close as possible to «dynamic» Groovy 53
Statically compiled & dynamic methods @CompileStatic String  greeting(String  name)  {        //  call  method  with  dynamic  behavior        //  but  with  proper  signature        generateMarkup(name.toUpperCase()) }   //  usual  dynamic  behavior String  generateMarkup(String  name)  {        def  sw  =  new  StringWriter()        new  MarkupBuilder(sw).html  {                body  {                        div  name                }        }        sw.toString() } 54
What about performance? • Comparisons between: • Java • Groovy static compilation (Groovy 2.0) • Groovy with primitive opts (Groovy 1.8+) • Groovy without optimizations (≤ Groovy 1.7) 55
What about performance? Fibonacci Pi (π) quadrature Binary trees Java 143 ms 93 ms 4.5 s Static 1.7 1.8 2.0 145 ms 96 ms 6.9 s compilation Primitive 271 ms 103 ms 29.6 s optimizations No primitive 3200 ms 2590 ms 50.0 s optimizations 56
Summary • Main themes of the Groovy 2.0 release •Modularity • Embark the JDK 7 enhancements •Project Coin •Invoke Dynamic • Static aspects • Static type checking • Static compilation 57
Summary ROCKS! 58
59
Thank you! ge me Lafor lopment Guillau roovy Deve fG Head o il.com orge @gma Em ail: glaf laforge orge r : @g .to/glaf om Twitte : http://gplus spot.c + p Google p://glaforge.ap tt Blog: h 60
Questions & Answers • Got questions, really? Q&A 61
Image credits • Bugs bunny: http://storage.canalblog.com/63/56/517188/47634843.jpeg • Iceberg: http://hqworld.net/gallery/data/media/20/tip_of_the_iceberg.jpg • Bicycle: http://drunkcyclist.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=2131&g2_serialNumber=2 • Pills: http://www.we-ew.com/wp-content/uploads/2011/01/plan-b-pills.jpg • Chains: http://2.bp.blogspot.com/-GXDVqUYSCa0/TVdBsON4tdI/AAAAAAAAAW4/EgJOUmAxB28/s1600/breaking-chains5_copy9611.jpg • Oui nide iou: http://desencyclopedie.wikia.com/wiki/Fichier:Superdupont_we_need_you.jpg • Guitar: http://www.lelitteraire.com/IMG/breveon323.jpg • Trampoline: http://www.fitness-online.fr/images/trampoline-1-m.jpg • Curry: http://www.pot-a-epices.com/wp-content/uploads/2009/02/curry1.jpg • Slurp: http://www.ohpacha.com/218-532-thickbox/gamelle-slurp.jpg • Caution: http://www.jeunes-epinay-sur-seine.fr/wp-content/uploads/2010/11/caution-colocation.jpg • Grumpy: http://mafeuilledechou.fr/__oneclick_uploads/2010/05/grumpy.jpg • Modularity: http://php.jglobal.com/blog/wp-content/uploads/2009/11/modularity.jpg • Agenda: http://www.plombiereslesbains.fr/images/stories/agenda.jpg • Java 7: http://geeknizer.com/wp-content/uploads/java7.jpg • WIP: http://www.connetport.com/wp-content/uploads/Work_in_progress.svg_.png • Grumpy 2: http://grumpy.division-par-zero.fr/wp-content/images/grumpy.jpg • Road Runner: http://newspaper.li/static/4ada046b7772f0612fec4e3840142308.jpg • Porky: http://joshuadsandy.files.wordpress.com/2011/05/porky-pig-5.jpg • Will E help: http://www.clipart-fr.com/data/clipart/looney/looney_004.jpg • Coyote road runner: http://www.jenkle.com/wp-content/uploads/2010/12/coyote-wallpaper1.jpg • Bunny your turn: http://media.onsugar.com/files/2011/04/17/6/1437/14373728/0fff82f316705e6a_bugs-bunny.png • Comics bubble: http://ryan110gs.edublogs.org/files/2010/11/Speech_bubble_600x452-1grpxu6.png 62

More Related Content

PDF
Groovy 1.8 et 2.0 au BreizhC@mp 2012
byGuillaume Laforge
 
KEY
Groovy Update, new in 1.8 and beyond - Guillaume Laforge - Devoxx 2011
byGuillaume Laforge
 
PDF
Groovy 2.0 update at Devoxx 2012
byGuillaume Laforge
 
PDF
Groovy update at SpringOne2GX 2012
byGuillaume Laforge
 
KEY
JavaOne 2012 Groovy update
byGuillaume Laforge
 
PDF
Groovy 1.8 and 2.0 at GR8Conf Europe 2012
byGuillaume Laforge
 
PDF
Groovy Update - Guillaume Laforge - Greach 2011
byGuillaume Laforge
 
PDF
Groovy 2.0 - Devoxx France 2012
byGuillaume Laforge
 
Groovy 1.8 et 2.0 au BreizhC@mp 2012
byGuillaume Laforge
 
Groovy Update, new in 1.8 and beyond - Guillaume Laforge - Devoxx 2011
byGuillaume Laforge
 
Groovy 2.0 update at Devoxx 2012
byGuillaume Laforge
 
Groovy update at SpringOne2GX 2012
byGuillaume Laforge
 
JavaOne 2012 Groovy update
byGuillaume Laforge
 
Groovy 1.8 and 2.0 at GR8Conf Europe 2012
byGuillaume Laforge
 
Groovy Update - Guillaume Laforge - Greach 2011
byGuillaume Laforge
 
Groovy 2.0 - Devoxx France 2012
byGuillaume Laforge
 

What's hot

KEY
Groovy update - S2GForum London 2011 - Guillaume Laforge
byGuillaume Laforge
 
PDF
Whats new in Groovy 2.0?
byGuillaume Laforge
 
PDF
Cacoo enterprise installation_manual
byjoseig23
 
PDF
Advanced GAR
bydmichelsen
 
PDF
Athenticated smaba server config with open vpn
byChanaka Lasantha
 
PDF
PostgreSQL Performance Tuning
byelliando dias
 
PDF
Go replicator
byCommand Prompt., Inc
 
PDF
Refcard en-a4
byArduino Aficionado
 
PDF
23769377 lab-bgp-juniper
bycavang_3004
 
ODP
Intro to Testing in Zope, Plone
byQuintagroup
 
PPT
My sql with querys
byNIRMAL FELIX
 
PDF
MySql 5.7 Backup Script
byHızlan ERPAK
 
Groovy update - S2GForum London 2011 - Guillaume Laforge
byGuillaume Laforge
 
Whats new in Groovy 2.0?
byGuillaume Laforge
 
Cacoo enterprise installation_manual
byjoseig23
 
Advanced GAR
bydmichelsen
 
Athenticated smaba server config with open vpn
byChanaka Lasantha
 
PostgreSQL Performance Tuning
byelliando dias
 
Go replicator
byCommand Prompt., Inc
 
Refcard en-a4
byArduino Aficionado
 
23769377 lab-bgp-juniper
bycavang_3004
 
Intro to Testing in Zope, Plone
byQuintagroup
 
My sql with querys
byNIRMAL FELIX
 
MySql 5.7 Backup Script
byHızlan ERPAK
 

More from Guillaume Laforge

PDF
Lift off with Groovy 2 at JavaOne 2013
byGuillaume Laforge
 
PDF
Groovy workshop à Mix-IT 2013
byGuillaume Laforge
 
PDF
Les nouveautés de Groovy 2 -- Mix-IT 2013
byGuillaume Laforge
 
PDF
Groovy 2 and beyond
byGuillaume Laforge
 
PDF
Groovy 2.0 webinar
byGuillaume Laforge
 
PDF
Groovy Domain Specific Languages - SpringOne2GX 2012
byGuillaume Laforge
 
PDF
Going to Mars with Groovy Domain-Specific Languages
byGuillaume Laforge
 
PDF
GPars et PrettyTime - Paris JUG 2011 - Guillaume Laforge
byGuillaume Laforge
 
KEY
Gaelyk update - Guillaume Laforge - SpringOne2GX 2011
byGuillaume Laforge
 
KEY
Groovy Update, what's new in Groovy 1.8 and beyond - Guillaume Laforge - Spri...
byGuillaume Laforge
 
KEY
Groovy DSLs, from Beginner to Expert - Guillaume Laforge and Paul King - Spri...
byGuillaume Laforge
 
KEY
Cloud foundry intro with groovy
byGuillaume Laforge
 
KEY
Groovy DSLs - S2GForum London 2011 - Guillaume Laforge
byGuillaume Laforge
 
PDF
Gaelyk - Guillaume Laforge - GR8Conf Europe 2011
byGuillaume Laforge
 
PDF
Groovy 1.8 update - Guillaume Laforge - GR8Conf Europe 2011
byGuillaume Laforge
 
KEY
Gaelyk - JFokus 2011 - Guillaume Laforge
byGuillaume Laforge
 
KEY
Groovy Ecosystem - JFokus 2011 - Guillaume Laforge
byGuillaume Laforge
 
KEY
Groovy and Gaelyk - Lausanne JUG 2011 - Guillaume Laforge
byGuillaume Laforge
 
KEY
Gaelyk - Paris GGUG 2011 - Guillaume Laforge
byGuillaume Laforge
 
PDF
Gaelyk - Groovy Grails eXchange 2010 - Guillaume Laforge
byGuillaume Laforge
 
Lift off with Groovy 2 at JavaOne 2013
byGuillaume Laforge
 
Groovy workshop à Mix-IT 2013
byGuillaume Laforge
 
Les nouveautés de Groovy 2 -- Mix-IT 2013
byGuillaume Laforge
 
Groovy 2 and beyond
byGuillaume Laforge
 
Groovy 2.0 webinar
byGuillaume Laforge
 
Groovy Domain Specific Languages - SpringOne2GX 2012
byGuillaume Laforge
 
Going to Mars with Groovy Domain-Specific Languages
byGuillaume Laforge
 
GPars et PrettyTime - Paris JUG 2011 - Guillaume Laforge
byGuillaume Laforge
 
Gaelyk update - Guillaume Laforge - SpringOne2GX 2011
byGuillaume Laforge
 
Groovy Update, what's new in Groovy 1.8 and beyond - Guillaume Laforge - Spri...
byGuillaume Laforge
 
Groovy DSLs, from Beginner to Expert - Guillaume Laforge and Paul King - Spri...
byGuillaume Laforge
 
Cloud foundry intro with groovy
byGuillaume Laforge
 
Groovy DSLs - S2GForum London 2011 - Guillaume Laforge
byGuillaume Laforge
 
Gaelyk - Guillaume Laforge - GR8Conf Europe 2011
byGuillaume Laforge
 
Groovy 1.8 update - Guillaume Laforge - GR8Conf Europe 2011
byGuillaume Laforge
 
Gaelyk - JFokus 2011 - Guillaume Laforge
byGuillaume Laforge
 
Groovy Ecosystem - JFokus 2011 - Guillaume Laforge
byGuillaume Laforge
 
Groovy and Gaelyk - Lausanne JUG 2011 - Guillaume Laforge
byGuillaume Laforge
 
Gaelyk - Paris GGUG 2011 - Guillaume Laforge
byGuillaume Laforge
 
Gaelyk - Groovy Grails eXchange 2010 - Guillaume Laforge
byGuillaume Laforge
 

Recently uploaded

PDF
[BDD 2025 - Full-Stack Development] Agentic AI Architecture: Redefining Syste...
byWintari Yasmin
 
PDF
MuleSoft Meetup: Dreamforce'25 Tour- Vibing With AI & Agents.pdf
byTintu Jacob Shaji
 
PDF
The Evolving Role of the CEO in the Age of AI
byPipal Tree Services Executive Search Firm
 
PDF
[BDD 2025 - Full-Stack Development] The Modern Stack: Building Web & AI Appli...
byWintari Yasmin
 
PDF
Mulesoft Meetup Online Portuguese: MCP e IA
byPedro Baroni
 
PDF
DUBAI IT MODERNIZATION WITH AZURE MANAGED SERVICES.pdf
byLogicEra
 
PDF
[DevFest Strasbourg 2025] - NodeJs Can do that !!
bymoassiongbon
 
PPTX
kernel PPT (Explanation of Windows Kernal).pptx
byINFOBYTES1
 
PDF
The partnership effect: Libraries and publishers on collaborating and thrivin...
byBookNet Canada
 
PDF
Crane Accident Prevention Guide: Key OSHA Regulations for Safer Operations
bySharpEagle Technology
 
PDF
5 Common Supply Chain Attacks and How They Work | CyberPro Magazine
byCyberPro Magazine
 
PPTX
Leon Brands - Intro to GPU Occlusion (Graphics Programming Conference 2024)
byleonbrands1998
 
PDF
Top Crypto Supers 15th Report November 2025
byStephen Perrenod
 
PDF
Lets Build a Serverless Function with Kiro
byChris Bingham
 
PDF
[BDD 2025 - Artificial Intelligence] Building AI Systems That Users (and Comp...
byWintari Yasmin
 
PPTX
Connecting the unconnectable: Exploring LoRaWAN for IoT
byasasiraarthur
 
PPTX
UFCD 0797 - SISTEMAS OPERATIVOS_Unidade Completa.pptx
byscribddobruno
 
PPTX
MuleSoft AI Series : Introduction to MCP
byMulesoftMunichMeetup
 
PDF
[BDD 2025 - Artificial Intelligence] AI for the Underdogs: Innovation for Sma...
byWintari Yasmin
 
PDF
ODSC AI West: Agent Optimization: Beyond Context engineering
byShashikant Jagtap
 
[BDD 2025 - Full-Stack Development] Agentic AI Architecture: Redefining Syste...
byWintari Yasmin
 
MuleSoft Meetup: Dreamforce'25 Tour- Vibing With AI & Agents.pdf
byTintu Jacob Shaji
 
The Evolving Role of the CEO in the Age of AI
byPipal Tree Services Executive Search Firm
 
[BDD 2025 - Full-Stack Development] The Modern Stack: Building Web & AI Appli...
byWintari Yasmin
 
Mulesoft Meetup Online Portuguese: MCP e IA
byPedro Baroni
 
DUBAI IT MODERNIZATION WITH AZURE MANAGED SERVICES.pdf
byLogicEra
 
[DevFest Strasbourg 2025] - NodeJs Can do that !!
bymoassiongbon
 
kernel PPT (Explanation of Windows Kernal).pptx
byINFOBYTES1
 
The partnership effect: Libraries and publishers on collaborating and thrivin...
byBookNet Canada
 
Crane Accident Prevention Guide: Key OSHA Regulations for Safer Operations
bySharpEagle Technology
 
5 Common Supply Chain Attacks and How They Work | CyberPro Magazine
byCyberPro Magazine
 
Leon Brands - Intro to GPU Occlusion (Graphics Programming Conference 2024)
byleonbrands1998
 
Top Crypto Supers 15th Report November 2025
byStephen Perrenod
 
Lets Build a Serverless Function with Kiro
byChris Bingham
 
[BDD 2025 - Artificial Intelligence] Building AI Systems That Users (and Comp...
byWintari Yasmin
 
Connecting the unconnectable: Exploring LoRaWAN for IoT
byasasiraarthur
 
UFCD 0797 - SISTEMAS OPERATIVOS_Unidade Completa.pptx
byscribddobruno
 
MuleSoft AI Series : Introduction to MCP
byMulesoftMunichMeetup
 
[BDD 2025 - Artificial Intelligence] AI for the Underdogs: Innovation for Sma...
byWintari Yasmin
 
ODSC AI West: Agent Optimization: Beyond Context engineering
byShashikant Jagtap
 

Groovy 2.0 update - Cloud Foundry Open Tour Moscow - Guillaume Laforge

  • 1.
    Groovy 2.0 What’s up,Doc? Guillaume Laforge Groovy Project Manager SpringSource / VMware @glaforge 1
  • 2.
    Groovy 2.0 What’s up,Doc? Guillaume Laforge Groovy Project Manager SpringSource / VMware @glaforge 1
  • 3.
    Guillaume Laforge • Groovy Project Manager at VMware •Initiator of the Grails framework •Creator of the Gaelyk and Caelyf toolkits • Co-author of Groovy in Action • Follow me on... •My blog: http://glaforge.appspot.com •Twitter: @glaforge •Google+: http://gplus.to/glaforge 2
  • 4.
    Agenda (1/2) • What’snew in Groovy 1.8? • Nicer DSLs with command chains • Runtime performance improvements • GPars bundled for taming your multicores • Closure enhancements • Builtin JSON support • New AST transformations 3
  • 5.
    Agenda (2/2) • What’scooking for Groovy 2.0? • Alignments with JDK 7 • Project Coin (small language changes) • Invoke Dynamic support • Continued runtime performance improvements • Static type checking • Static compilation • Modularity 4
  • 6.
    Command chains • A grammar improvement allowing you to drop dots & parens when chaining method calls • an extended version of top-level statements like println • Less dots, less parens allow you to •write more readable business rules •in almost plain English sentences • (or any language, of course) 5
  • 7.
    Command chains  turn  left    then  right   6
  • 8.
    Command chains Alternation of method names  turn  left    then  right   6
  • 9.
    Command chains Alternation of method names  turn  left    then  right   and parameters (even named ones) 6
  • 10.
    Command chains  turn  left    then  right   6
  • 11.
    Command chains Equivalent to:          (        ).        (          )  turn  left    then  right   6
  • 12.
    Look Ma! No par ens, no dots!
  • 13.
    Command chains take  2    pills  of    chloroquinine    after    6  hours 8
  • 14.
    Command chains        (  ).          (    ).                            (          ).  (          ) take  2    pills  of    chloroquinine    after    6  hours 8
  • 15.
  • 16.
    Command chains //  methods  with  multiple  arguments  (commas) 9
  • 17.
    Command chains //  methods  with  multiple  arguments  (commas) take  coffee    with  sugar,  milk    and  liquor 9
  • 18.
    Command chains //  methods  with  multiple  arguments  (commas) take  coffee    with  sugar,  milk    and  liquor //  leverage  named-­‐args  as  punctuation 9
  • 19.
    Command chains //  methods  with  multiple  arguments  (commas) take  coffee    with  sugar,  milk    and  liquor //  leverage  named-­‐args  as  punctuation check  that:  margarita    tastes  good 9
  • 20.
    Command chains //  methods  with  multiple  arguments  (commas) take  coffee    with  sugar,  milk    and  liquor //  leverage  named-­‐args  as  punctuation check  that:  margarita    tastes  good //  closure  parameters  for  new  control  structures 9
  • 21.
    Command chains //  methods  with  multiple  arguments  (commas) take  coffee    with  sugar,  milk    and  liquor //  leverage  named-­‐args  as  punctuation check  that:  margarita    tastes  good //  closure  parameters  for  new  control  structures given  {}    when  {}    then  {} 9
  • 22.
    Command chains //  methods  with  multiple  arguments  (commas) take  coffee    with  sugar,  milk    and  liquor //  leverage  named-­‐args  as  punctuation check  that:  margarita    tastes  good //  closure  parameters  for  new  control  structures given  {}    when  {}    then  {} //  zero-­‐arg  methods  require  parens 9
  • 23.
    Command chains //  methods  with  multiple  arguments  (commas) take  coffee    with  sugar,  milk    and  liquor //  leverage  named-­‐args  as  punctuation check  that:  margarita    tastes  good //  closure  parameters  for  new  control  structures given  {}    when  {}    then  {} //  zero-­‐arg  methods  require  parens select  all    unique()  from  names 9
  • 24.
    Command chains //  methods  with  multiple  arguments  (commas) take  coffee    with  sugar,  milk    and  liquor //  leverage  named-­‐args  as  punctuation check  that:  margarita    tastes  good //  closure  parameters  for  new  control  structures given  {}    when  {}    then  {} //  zero-­‐arg  methods  require  parens select  all    unique()  from  names //  possible  with  an  odd  number  of  terms 9
  • 25.
    Command chains //  methods  with  multiple  arguments  (commas) take  coffee    with  sugar,  milk    and  liquor //  leverage  named-­‐args  as  punctuation check  that:  margarita    tastes  good //  closure  parameters  for  new  control  structures given  {}    when  {}    then  {} //  zero-­‐arg  methods  require  parens select  all    unique()  from  names //  possible  with  an  odd  number  of  terms take  3    cookies 9
  • 26.
    Command chains //  methods  with  multiple  arguments  (commas) take  coffee    with  sugar,  milk    and  liquor        (            ).        (                      ).      (            ) //  leverage  named-­‐args  as  punctuation check  that:  margarita    tastes  good //  closure  parameters  for  new  control  structures given  {}    when  {}    then  {} //  zero-­‐arg  methods  require  parens select  all    unique()  from  names //  possible  with  an  odd  number  of  terms take  3    cookies 9
  • 27.
    Command chains //  methods  with  multiple  arguments  (commas) take  coffee    with  sugar,  milk    and  liquor        (            ).        (                      ).      (            ) //  leverage  named-­‐args  as  punctuation check  that:  margarita    tastes  good          (                              ).            (        ) //  closure  parameters  for  new  control  structures given  {}    when  {}    then  {} //  zero-­‐arg  methods  require  parens select  all    unique()  from  names //  possible  with  an  odd  number  of  terms take  3    cookies 9
  • 28.
    Command chains //  methods  with  multiple  arguments  (commas) take  coffee    with  sugar,  milk    and  liquor        (            ).        (                      ).      (            ) //  leverage  named-­‐args  as  punctuation check  that:  margarita    tastes  good          (                              ).            (        ) //  closure  parameters  for  new  control  structures given  {}    when  {}    then  {}          (    ).        (    ).        (    ) //  zero-­‐arg  methods  require  parens select  all    unique()  from  names //  possible  with  an  odd  number  of  terms take  3    cookies 9
  • 29.
    Command chains //  methods  with  multiple  arguments  (commas) take  coffee    with  sugar,  milk    and  liquor        (            ).        (                      ).      (            ) //  leverage  named-­‐args  as  punctuation check  that:  margarita    tastes  good          (                              ).            (        ) //  closure  parameters  for  new  control  structures given  {}    when  {}    then  {}          (    ).        (    ).        (    ) //  zero-­‐arg  methods  require  parens select  all    unique()  from  names            (      ).                .        (          ) //  possible  with  an  odd  number  of  terms take  3    cookies 9
  • 30.
    Command chains //  methods  with  multiple  arguments  (commas) take  coffee    with  sugar,  milk    and  liquor        (            ).        (                      ).      (            ) //  leverage  named-­‐args  as  punctuation check  that:  margarita    tastes  good          (                              ).            (        ) //  closure  parameters  for  new  control  structures given  {}    when  {}    then  {}          (    ).        (    ).        (    ) //  zero-­‐arg  methods  require  parens select  all    unique()  from  names            (      ).                .        (          ) //  possible  with  an  odd  number  of  terms take  3    cookies        (  ). 9
  • 31.
    GPars bundled • GPars is bundled in the Groovy distribution • GPars covers a wide range of parallel and concurrent paradigms • actors, fork/join, map/filter/reduce, dataflow, agents • parallel arrays, executors, STM, and more... • And you can use it from plain Java as well! 10
  • 32.
    Closure enhancements • Closureannotation parameters • Some more functional flavor •composition: compose several closures into one single closure •trampoline: avoid stack overflow errors for recursive algorithms •memoization: remember the outcome of previous closure invocations •currying improvements 11
  • 33.
    Closure annotation parameters @Retention(RetentionPolicy.RUNTIME) @interface  Invariant  {                Class  value()  //  a  closure  class }   { @Invariant({  number  >=  0  }) class  Distance  {                float  number                String  unit }     def  d  =  new  Distance(number:  10,  unit:  "meters")   def  anno  =  Distance.getAnnotation(Invariant) def  check  =  anno.value().newInstance(d,  d) assert  check(d) 12
  • 34.
    Closure annotation parameters @Retention(RetentionPolicy.RUNTIME) @interface  Invariant  {                Class  value()  //  a  closure  class }   { @Invariant({  number  >=  0  }) class  Distance  {                float  number         Poor -man ’s G Cont racts        String  unit }     def  d  =  new  Distance(number:  10,  unit:  "meters")   def  anno  =  Distance.getAnnotation(Invariant) def  check  =  anno.value().newInstance(d,  d) assert  check(d) 12
  • 35.
  • 36.
    Closure memoization def  plus  =  {  a,  b  -­‐>  sleep  1000;  a  +  b  }.memoize() 13
  • 37.
    Closure memoization def  plus  =  {  a,  b  -­‐>  sleep  1000;  a  +  b  }.memoize() assert  plus(1,  2)  ==  3  //  after  1000ms 13
  • 38.
    Closure memoization def  plus  =  {  a,  b  -­‐>  sleep  1000;  a  +  b  }.memoize() assert  plus(1,  2)  ==  3  //  after  1000ms assert  plus(1,  2)  ==  3  //  return  immediately 13
  • 39.
    Closure memoization def  plus  =  {  a,  b  -­‐>  sleep  1000;  a  +  b  }.memoize() assert  plus(1,  2)  ==  3  //  after  1000ms assert  plus(1,  2)  ==  3  //  return  immediately assert  plus(2,  2)  ==  4  //  after  1000ms 13
  • 40.
    Closure memoization def  plus  =  {  a,  b  -­‐>  sleep  1000;  a  +  b  }.memoize() assert  plus(1,  2)  ==  3  //  after  1000ms assert  plus(1,  2)  ==  3  //  return  immediately assert  plus(2,  2)  ==  4  //  after  1000ms assert  plus(2,  2)  ==  4  //  return  immediately     13
  • 41.
    Closure memoization def  plus  =  {  a,  b  -­‐>  sleep  1000;  a  +  b  }.memoize() assert  plus(1,  2)  ==  3  //  after  1000ms assert  plus(1,  2)  ==  3  //  return  immediately assert  plus(2,  2)  ==  4  //  after  1000ms assert  plus(2,  2)  ==  4  //  return  immediately       13
  • 42.
    Closure memoization def  plus  =  {  a,  b  -­‐>  sleep  1000;  a  +  b  }.memoize() assert  plus(1,  2)  ==  3  //  after  1000ms assert  plus(1,  2)  ==  3  //  return  immediately assert  plus(2,  2)  ==  4  //  after  1000ms assert  plus(2,  2)  ==  4  //  return  immediately       //  at  least  10  invocations  cached 13
  • 43.
    Closure memoization def  plus  =  {  a,  b  -­‐>  sleep  1000;  a  +  b  }.memoize() assert  plus(1,  2)  ==  3  //  after  1000ms assert  plus(1,  2)  ==  3  //  return  immediately assert  plus(2,  2)  ==  4  //  after  1000ms assert  plus(2,  2)  ==  4  //  return  immediately       //  at  least  10  invocations  cached def  plusAtLeast  =  {  ...  }.memoizeAtLeast(10) 13
  • 44.
    Closure memoization def  plus  =  {  a,  b  -­‐>  sleep  1000;  a  +  b  }.memoize() assert  plus(1,  2)  ==  3  //  after  1000ms assert  plus(1,  2)  ==  3  //  return  immediately assert  plus(2,  2)  ==  4  //  after  1000ms assert  plus(2,  2)  ==  4  //  return  immediately       //  at  least  10  invocations  cached def  plusAtLeast  =  {  ...  }.memoizeAtLeast(10)   13
  • 45.
    Closure memoization def  plus  =  {  a,  b  -­‐>  sleep  1000;  a  +  b  }.memoize() assert  plus(1,  2)  ==  3  //  after  1000ms assert  plus(1,  2)  ==  3  //  return  immediately assert  plus(2,  2)  ==  4  //  after  1000ms assert  plus(2,  2)  ==  4  //  return  immediately       //  at  least  10  invocations  cached def  plusAtLeast  =  {  ...  }.memoizeAtLeast(10)   //  at  most  10  invocations  cached 13
  • 46.
    Closure memoization def  plus  =  {  a,  b  -­‐>  sleep  1000;  a  +  b  }.memoize() assert  plus(1,  2)  ==  3  //  after  1000ms assert  plus(1,  2)  ==  3  //  return  immediately assert  plus(2,  2)  ==  4  //  after  1000ms assert  plus(2,  2)  ==  4  //  return  immediately       //  at  least  10  invocations  cached def  plusAtLeast  =  {  ...  }.memoizeAtLeast(10)   //  at  most  10  invocations  cached def  plusAtMost  =  {  ...  }.memoizeAtMost(10)   13
  • 47.
    Closure memoization def  plus  =  {  a,  b  -­‐>  sleep  1000;  a  +  b  }.memoize() assert  plus(1,  2)  ==  3  //  after  1000ms assert  plus(1,  2)  ==  3  //  return  immediately assert  plus(2,  2)  ==  4  //  after  1000ms assert  plus(2,  2)  ==  4  //  return  immediately       //  at  least  10  invocations  cached def  plusAtLeast  =  {  ...  }.memoizeAtLeast(10)   //  at  most  10  invocations  cached def  plusAtMost  =  {  ...  }.memoizeAtMost(10)   //  between  10  and  20  invocations  cached 13
  • 48.
    Closure memoization def  plus  =  {  a,  b  -­‐>  sleep  1000;  a  +  b  }.memoize() assert  plus(1,  2)  ==  3  //  after  1000ms assert  plus(1,  2)  ==  3  //  return  immediately assert  plus(2,  2)  ==  4  //  after  1000ms assert  plus(2,  2)  ==  4  //  return  immediately       //  at  least  10  invocations  cached def  plusAtLeast  =  {  ...  }.memoizeAtLeast(10)   //  at  most  10  invocations  cached def  plusAtMost  =  {  ...  }.memoizeAtMost(10)   //  between  10  and  20  invocations  cached def  plusAtLeast  =  {  ...  }.memoizeBetween(10,  20) 13
  • 49.
    Builtin JSON support • Consuming • Producing • Pretty-printing 14
  • 50.
    Builtin JSON support import  groovy.json.*   def  payload  =  new  URL(        "http://github.../json/commits/...").text   def  slurper  =  new  JsonSlurper() def  doc  =  slurper.parseText(payload)   doc.commits.message.each  {  println  it  } 15
  • 51.
    Builtin JSON support import  groovy.json.*     def  json  =  new  JsonBuilder()     json.person  {                name  "Guillaume"        age  34                pets  "Hector",  "Felix" }   println  json.toString() 16
  • 52.
    Builtin JSON support import  groovy.json.*     def  json  =  new  JsonBuilder()     {         json.person  {                "person":  {                        name  "Guillaume"                "name":  "Guillaume",              age  34                        "age":  34,                                "pets":  [                                pets  "Hector",  "Felix"                        "Hector",                     }                          "Felix"                 println  json.toString()                ]                } } 16
  • 53.
    Builtin JSON support import  groovy.json.*     println  JsonOutput.prettyPrint(        '''{"person":{"name":"Guillaume","age":34,'''  +          '''"pets":["Hector","Felix"]}}''')   {                "person":  {                                "name":  "Guillaume",                    "age":  34,                                "pets":  [                                                "Hector",                                          "Felix"                                ]                } } 17
  • 54.
    New AST transformations • @Log • Controlling execution • @ThreadInterrupt • @Field • @TimedInterrupt • @ConditionalInterrupt • @AutoClone • @InheritConstructor • @AutoExternalizable • @WithReadLock • @Canonical • @WithWriteLock • @ToString • @EqualsAndHashCode • @TupleConstructor • @ListenerList 18
  • 55.
    @Log • Four different loggers can be injected import  groovy.util.logging.*   •@Log   •@Commons @Log class  Car  {         •@Log4j        Car()  {                 •@Slf4j                log.info  'Car  built'                } }     • Possible to implement def  c  =  new  Car() your own strategy 19
  • 56.
    @Log • Four different loggers can be injected import  groovy.util.logging.*   •@Log   •@Commons @Log class  Car  {         •@Log4j        Car()  {                 •@Slf4j Guarded w/ an if                log.info  'Car  built'                } }     • Possible to implement def  c  =  new  Car() your own strategy 19
  • 57.
    Controlling code execution • Your application may run user’s code •what if the code runs in infinite loops or for too long? •what if the code consumes too many resources? • 3 new transforms at your rescue • @ThreadInterrupt: adds Thread#isInterrupted checks so your executing thread stops when interrupted • @TimedInterrupt: adds checks in method and closure bodies to verify it’s run longer than expected • @ConditionalInterrupt: adds checks with your own conditional logic to break out from the user code 20
  • 58.
    @ThreadInterrupt @ThreadInterrupt import  groovy.transform.ThreadInterrupt     while  (true)  {        //  eat  lots  of  CPU } 21 33
  • 59.
    @ThreadInterrupt @ThreadInterrupt import  groovy.transform.ThreadInterrupt     while  (true)  { {        if  (Thread.currentThread.isInterrupted())                throw  new  InterruptedException() }        //  eat  lots  of  CPU } 21 33
  • 60.
    @ToString • Provides a default toString() method to your types • Available annotation options • includeNames, includeFields, includeSuper, excludes import  groovy.transform.ToString     @ToString class  Person  {                String  name                int  age }     println  new  Person(name:  'Pete',  age:  15) //  =>  Person(Pete,  15) 22
  • 61.
    @EqualsAndHashCode • Provides default implementations for equals() and hashCode() methods import  groovy.transform.EqualsAndHashCode     @EqualsAndHashCode class  Coord  {                int  x,  y }     def  c1  =  new  Coord(x:  20,  y:  5) def  c2  =  new  Coord(x:  20,  y:  5)     assert  c1  ==  c2 assert  c1.hashCode()  ==  c2.hashCode() 23
  • 62.
    @TupleConstructor • Provides a «classical» constructor with all properties • Several annotation parameter options available import  groovy.transform.TupleConstructor     @TupleConstructor   class  Person  {                String  name                int  age }     def  m  =  new  Person('Marion',  4)               assert  m.name  ==  'Marion' assert  m.age    ==  4 24
  • 63.
    @InheritConstructors • Classes like Exception are painful when extended, as all the base constructors should be replicated class  CustomException  extends  Exception  {        CustomException()                                                {  super()              }        CustomException(String  msg)                            {  super(msg)        }        CustomException(String  msg,  Throwable  t)  {  super(msg,  t)  }        CustomException(Throwable  t)                          {  super(t)            } } 25
  • 64.
    @InheritConstructors • Classes like Exception are painful when extended, as all the base constructors should be replicated import  groovy.transform.* @InheritConstructors class  CustomException  extends  Exception  {        CustomException()                                                {  super()              }        CustomException(String  msg)                            {  super(msg)        }        CustomException(String  msg,  Throwable  t)  {  super(msg,  t)  }        CustomException(Throwable  t)                          {  super(t)            } } 25
  • 65.
    Miscelanous • Compilation customizers • Java 7 diamond operator • Slashy and dollar slashy strings • New GDK methods • (G)String to Enum coercion • Customizing the Groovysh prompt • Executing remote scripts 26
  • 66.
    Compilation customizers • Ability to apply some customization to the Groovy compilation process • Three available customizers •ImportCustomizer •ASTTransformationCustomizer •SecureASTCustomizer • But you can implement your own 27
  • 67.
    Imports customizer def  configuration  =  new  CompilerConfiguration()   def  custo  =  new  ImportCustomizer() custo.addStaticStar(Math.name) configuration.addCompilationCustomizers(custo)     def  result  =  new  GroovyShell(configuration)                          //  import  static  java.lang.Math.*        .evaluate("  cos  PI/3  ")                             28
  • 68.
  • 69.
    Groovy 2.0 roadmap • Towards a more modular Groovy • Java 7 alignements: Project Coin • binary literals • underscore in literals • multicatch • JDK 7: InvokeDynamic • Static type checking • Static compilation 30
  • 70.
    Groovy Modularity • Groovy’s «all» JAR weighs in at 4MB • Nobody needs everything • Template engine, Ant scripting, Swing UI building... • Provide a smaller core • and several smaller JARs per feature • Provide hooks for setting up DGM methods, etc. 31
  • 71.
    Java 7 /JDK 7 • Project Coin and InvokeDynamic 32
  • 72.
    Binary literals • We had decimal, octal and hexadecimal notations for number literals • We can now use binary representations too int  x  =  0b10101111 assert  x  ==  175   byte  aByte  =  0b00100001 assert  aByte  ==  33   int  anInt  =  0b1010000101000101 assert  anInt  ==  41285 33
  • 73.
    Underscore in literals • Now we can also add underscores in number literals for more readability long  creditCardNumber  =  1234_5678_9012_3456L long  socialSecurityNumbers  =  999_99_9999L float  monetaryAmount  =  12_345_132.12 long  hexBytes  =  0xFF_EC_DE_5E long  hexWords  =  0xFFEC_DE5E long  maxLong  =  0x7fff_ffff_ffff_ffffL long  alsoMaxLong  =  9_223_372_036_854_775_807L long  bytes  =  0b11010010_01101001_10010100_10010010 34
  • 74.
    Multicatch • One block for multiple exception caught •rather than duplicating the block try  {        /*  ...  */ }  catch(IOException  |  NullPointerException  e)  {        /*  one  block  to  treat  2  exceptions  */ } 35
  • 75.
    InvokeDynamic • Groovy 2.0supports JDK 7’s invokeDynamic • compiler has a flag for compiling against JDK 7 • might use the invokeDynamic backport for < JDK 7 • Benefits • more runtime performance! • at least as fast as current «dynamic» Groovy •in the long run, will allow us to get rid of code! • call site caching, thanks to MethodHandles • metaclass registry, thanks to ClassValues • will let the JIT inline calls more easily 36
  • 76.
    Static Type Checking • Goal: make the Groovy compiler «grumpy»! • and throw compilation errors (not at runtime) • Not everybody needs dynamic features all the time • think Java libraries scripting • Grumpy should... • tell you about your method or variable typos • complain if you call methods that don’t exist • shout on assignments of wrong types • infer the types of your variables • figure out GDK methods • etc... 37
  • 77.
    Typos in yourvars or methods import  groovy.transform.TypeChecked   void  method()  {}   @TypeChecked  test()  {        //  Cannot  find  matching  method  metthhoood()        metthhoood()          def  name  =  "Guillaume"        //  variable  naamme  is  undeclared        println  naamme } 38
  • 78.
    Typos in yourvars or methods import  groovy.transform.TypeChecked   void  method()  {}   @TypeChecked  test()  {        //  Cannot  find  matching  method  metthhoood()        metthhoood()   Compilation        def  name  =  "Guillaume" errors!        //  variable  naamme  is  undeclared        println  naamme } 38
  • 79.
    Typos in yourvars or methods import  groovy.transform.TypeChecked Annotation can be at   class or method level void  method()  {}   @TypeChecked  test()  {        //  Cannot  find  matching  method  metthhoood()        metthhoood()   Compilation        def  name  =  "Guillaume" errors!        //  variable  naamme  is  undeclared        println  naamme } 38
  • 80.
    Complain on wrongassignments //  cannot  assign  value  of  type...  to  variable... int  x  =  new  Object() Set  set  =  new  Object()   def  o  =  new  Object() int  x  =  o   String[]  strings  =  ['a','b','c'] int  str  =  strings[0]   //  cannot  find  matching  method  plus() int  i  =  0 i  +=  '1' 39
  • 81.
    Complain on wrongassignments //  cannot  assign  value  of  type...  to  variable... int  x  =  new  Object() Set  set  =  new  Object() Compilation   errors! def  o  =  new  Object() int  x  =  o   String[]  strings  =  ['a','b','c'] int  str  =  strings[0]   //  cannot  find  matching  method  plus() int  i  =  0 i  +=  '1' 39
  • 82.
    Complain on wrongreturn types //  checks  if/else  branch  return  values @TypeChecked int  method()  {        if  (true)  {  'String'  }        else  {  42  } } //  works  for  switch/case  &  try/catch/finally   //  transparent  toString()  implied @TypeChecked String  greeting(String  name)  {        def  sb  =  new  StringBuilder()        sb  <<  "Hi  "  <<  name } 40
  • 83.
    Complain on wrongreturn types //  checks  if/else  branch  return  values @TypeChecked int  method()  { Compilation        if  (true)  {  'String'  } error!        else  {  42  } } //  works  for  switch/case  &  try/catch/finally   //  transparent  toString()  implied @TypeChecked String  greeting(String  name)  {        def  sb  =  new  StringBuilder()        sb  <<  "Hi  "  <<  name } 40
  • 84.
    Type inference @TypeChecked  test()  {        def  name  =  "    Guillaume    "          //  String  type  infered  (even  inside  GString)        println  "NAME  =  ${name.toUpperCase()}"            //  Groovy  GDK  method  support        //  (GDK  operator  overloading  too)        println  name.trim()          int[]  numbers  =  [1,  2,  3]        //  Element  n  is  an  int        for  (int  n  in  numbers)  {                println  n        } } 41
  • 85.
    Statically checked &dynamic methods @TypeChecked String  greeting(String  name)  {        //  call  method  with  dynamic  behavior        //  but  with  proper  signature        generateMarkup(name.toUpperCase()) }   //  usual  dynamic  behavior String  generateMarkup(String  name)  {        def  sw  =  new  StringWriter()        new  MarkupBuilder(sw).html  {                body  {                        div  name                }        }        sw.toString() } 42
  • 86.
    Instanceof checks @TypeChecked   void  test(Object  val)  {        if  (val  instanceof  String)  {                println  val.toUpperCase()        }  else  if  (val  instanceof  Number)  {                println  "X"  *  val.intValue()        } } 43
  • 87.
    Instanceof checks @TypeChecked   No need void  test(Object  val)  { for casts        if  (val  instanceof  String)  {                println  val.toUpperCase()        }  else  if  (val  instanceof  Number)  {                println  "X"  *  val.intValue()        } } 43
  • 88.
    Instanceof checks @TypeChecked   No need void  test(Object  val)  { for casts        if  (val  instanceof  String)  {                println  val.toUpperCase()        }  else  if  (val  instanceof  Number)  {                println  "X"  *  val.intValue()        } } Can call String#multiply(int) from the Groovy Development Kit 43
  • 89.
    Lowest Upper Bound • Represents the lowest «super» type that classes have in common •may be virtual (aka «non-denotable») @TypeChecked  test()  {        //  an  integer  and  a  BigDecimal        return  [1234,  3.14] } 44
  • 90.
    Lowest Upper Bound • Represents the lowest «super» type that classes have in common •may be virtual (aka «non-denotable») @TypeChecked  test()  {        //  an  integer  and  a  BigDecimal        return  [1234,  3.14] } Inferred return type: List<Number> 44
  • 91.
    Flow typing • Static type checking shouldn’t complain even for bad coding practicies which work without type checks @TypeChecked  test()  {        def  var  =  123                  //  inferred  type  is  int        int  x  =  var                      //  var  is  an  int        var  =  "123"                      //  assign  var  with  a  String        x  =  var.toInteger()      //  no  problem,  no  need  to  cast        var  =  123        x  =  var.toUpperCase()  //  error,  var  is  int! } 45
  • 92.
    Gotchas: static checkingvs dynamic • Type checking works at compile-time • adding @TypeChecked doesn’t change behavior • do not confuse with static compilation • Most dynamic features cannot be type checked •metaclass changes, categories •dynamically bound variables (ex: script’s binding) • However, compile-time metaprogramming works •as long as proper type information is defined 46
  • 93.
    Gotchas: runtime metaprogramming @TypeChecked   void  test()  {        Integer.metaClass.foo  =  {}        123.foo() } 47
  • 94.
    Gotchas: runtime metaprogramming @TypeChecked   void  test()  {        Integer.metaClass.foo  =  {}        123.foo() } Not allowed: metaClass property is dynamic 47
  • 95.
    Gotchas: runtime metaprogramming @TypeChecked   void  test()  {        Integer.metaClass.foo  =  {}        123.foo() } Method not Not allowed: recognized metaClass property is dynamic 47
  • 96.
    Gotchas: closures needexplicit types @TypeChecked  test()  {        ["a",  "b",  "c"].collect  {                it.toUpperCase()  //  Not  OK        } } • A «Groovy Enhancement Proposal» to address this issue 48
  • 97.
    Gotchas: closures needexplicit types @TypeChecked  test()  {        ["a",  "b",  "c"].collect  {  String  it  -­‐>                it.toUpperCase()  //  OK,  it’s  a  String        } } • A «Groovy Enhancement Proposal» to address this issue 48
  • 98.
    Closure shared variables @TypeChecked  test()  {        def  var  =  "abc"                      def  cl  =  {  var  =  new  Date()  }        cl()        var.toUpperCase()    //  Not  OK! } 49
  • 99.
    Closure shared variables var assigned in the closure: «shared closure variable» @TypeChecked  test()  {        def  var  =  "abc"                      def  cl  =  {  var  =  new  Date()  }        cl()        var.toUpperCase()    //  Not  OK! } 49
  • 100.
    Closure shared variables var assigned in the closure: «shared closure variable» @TypeChecked  test()  { Impossible to        def  var  =  "abc"               ensure        def  cl  =  {  var  =  new  Date()  } the assignment        cl() really happens        var.toUpperCase()    //  Not  OK! } 49
  • 101.
    Closure shared variables var assigned in the closure: «shared closure variable» @TypeChecked  test()  { Impossible to        def  var  =  "abc"               ensure        def  cl  =  {  var  =  new  Date()  } the assignment        cl() really happens        var.toUpperCase()    //  Not  OK! } Only methods of the most specific compatible type (LUB) are allowed by the type checker 49
  • 102.
    Closure shared variables class  A                      {  void  foo()  {}  } class  B  extends  A  {  void  bar()  {}  } @TypeChecked  test()  {        def  var  =  new  A()        def  cl  =  {  var  =  new  B()  }        cl()        var.foo()      //  OK! } 50
  • 103.
    Closure shared variables class  A                      {  void  foo()  {}  } class  B  extends  A  {  void  bar()  {}  } @TypeChecked  test()  {        def  var  =  new  A()        def  cl  =  {  var  =  new  B()  }        cl()        var.foo()      //  OK! } var is at least an instance of A 50
  • 104.
    Static Compilation • Given your Groovy code can be type checked... we can as well compile it «statically» • ie. generate the same byte code as javac • Also interesting for those stuck in JDK < 7 to benefit from performance improvements 51
  • 105.
    Static Compilation: advantages • You gain: • Type safety • thanks to static type checking • static compilation builds upon static type checking • Faster code • as close as possible to Java’s performance • Code immune to «monkey patching» • metaprogramming badly used can interfere with framework code • Smaller bytecode size 52
  • 106.
    Static Compilation: advantages • You gain: • Type safety • thanks to static type checking • static compilation builds upon static type checking • Faster code • as close as possible to Java’s performance • Code immune to «monkey patching» • metaprogramming badly used can interfere with framework code • Smaller bytecode size 52
  • 107.
    Static Compilation: disadvantages • But you loose: • Dynamic features •metaclass changes, categories, etc. • Dynamic method dispatch •although as close as possible to «dynamic» Groovy 53
  • 108.
    Statically compiled &dynamic methods @CompileStatic String  greeting(String  name)  {        //  call  method  with  dynamic  behavior        //  but  with  proper  signature        generateMarkup(name.toUpperCase()) }   //  usual  dynamic  behavior String  generateMarkup(String  name)  {        def  sw  =  new  StringWriter()        new  MarkupBuilder(sw).html  {                body  {                        div  name                }        }        sw.toString() } 54
  • 109.
    What about performance? • Comparisons between: • Java • Groovy static compilation (Groovy 2.0) • Groovy with primitive opts (Groovy 1.8+) • Groovy without optimizations (≤ Groovy 1.7) 55
  • 110.
    What about performance? Fibonacci Pi (π) quadrature Binary trees Java 143 ms 93 ms 4.5 s Static 1.7 1.8 2.0 145 ms 96 ms 6.9 s compilation Primitive 271 ms 103 ms 29.6 s optimizations No primitive 3200 ms 2590 ms 50.0 s optimizations 56
  • 111.
    Summary • Main themes of the Groovy 2.0 release •Modularity • Embark the JDK 7 enhancements •Project Coin •Invoke Dynamic • Static aspects • Static type checking • Static compilation 57
  • 112.
    Summary ROCKS! 58
  • 113.
  • 114.
    Thank you! ge me Lafor lopment Guillau roovy Deve fG Head o il.com orge @gma Em ail: glaf laforge orge r : @g .to/glaf om Twitte : http://gplus spot.c + p Google p://glaforge.ap tt Blog: h 60
  • 115.
    Questions & Answers • Got questions, really? Q&A 61
  • 116.
    Image credits • Bugs bunny: http://storage.canalblog.com/63/56/517188/47634843.jpeg • Iceberg: http://hqworld.net/gallery/data/media/20/tip_of_the_iceberg.jpg • Bicycle: http://drunkcyclist.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=2131&g2_serialNumber=2 • Pills: http://www.we-ew.com/wp-content/uploads/2011/01/plan-b-pills.jpg • Chains: http://2.bp.blogspot.com/-GXDVqUYSCa0/TVdBsON4tdI/AAAAAAAAAW4/EgJOUmAxB28/s1600/breaking-chains5_copy9611.jpg • Oui nide iou: http://desencyclopedie.wikia.com/wiki/Fichier:Superdupont_we_need_you.jpg • Guitar: http://www.lelitteraire.com/IMG/breveon323.jpg • Trampoline: http://www.fitness-online.fr/images/trampoline-1-m.jpg • Curry: http://www.pot-a-epices.com/wp-content/uploads/2009/02/curry1.jpg • Slurp: http://www.ohpacha.com/218-532-thickbox/gamelle-slurp.jpg • Caution: http://www.jeunes-epinay-sur-seine.fr/wp-content/uploads/2010/11/caution-colocation.jpg • Grumpy: http://mafeuilledechou.fr/__oneclick_uploads/2010/05/grumpy.jpg • Modularity: http://php.jglobal.com/blog/wp-content/uploads/2009/11/modularity.jpg • Agenda: http://www.plombiereslesbains.fr/images/stories/agenda.jpg • Java 7: http://geeknizer.com/wp-content/uploads/java7.jpg • WIP: http://www.connetport.com/wp-content/uploads/Work_in_progress.svg_.png • Grumpy 2: http://grumpy.division-par-zero.fr/wp-content/images/grumpy.jpg • Road Runner: http://newspaper.li/static/4ada046b7772f0612fec4e3840142308.jpg • Porky: http://joshuadsandy.files.wordpress.com/2011/05/porky-pig-5.jpg • Will E help: http://www.clipart-fr.com/data/clipart/looney/looney_004.jpg • Coyote road runner: http://www.jenkle.com/wp-content/uploads/2010/12/coyote-wallpaper1.jpg • Bunny your turn: http://media.onsugar.com/files/2011/04/17/6/1437/14373728/0fff82f316705e6a_bugs-bunny.png • Comics bubble: http://ryan110gs.edublogs.org/files/2010/11/Speech_bubble_600x452-1grpxu6.png 62