Your SlideShare is downloading. ×
0
Groovy 2.0What’s up, Doc?  Guillaume Laforge  Groovy Project Manager  SpringSource / VMware         @glaforge             ...
Groovy 2.0What’s up, Doc?  Guillaume Laforge  Groovy Project Manager  SpringSource / VMware         @glaforge             ...
Guillaume Laforge•   Groovy Project Manager at VMware    •Initiator of the Grails framework    •Creator of the Gaelyk     ...
Agenda (1/2)• What’s new in Groovy 1.8? • Nicer DSLs with command chains • Runtime performance improvements • GPars bundle...
Agenda (2/2)• What’s cooking for Groovy 2.0? • Alignments with JDK 7  • Project Coin (small language changes)  • Invoke Dy...
Command chains•   A grammar improvement allowing you    to drop dots & parens when chaining method calls    • an extended ...
Command chains       	  turn	  left	  	  then	  right	                                                     6
Command chains       Alternation of       method names       	  turn	  left	  	  then	  right	                            ...
Command chains       Alternation of       method names       	  turn	  left	  	  then	  right	                       and p...
Command chains       	  turn	  left	  	  then	  right	                                                     6
Command chains       Equivalent to:       	  	  	  	  	  (	  	  	  	  ).	  	  	  	  (	  	  	  	  	  )       	  turn	  left...
Look  Ma!No  par ens, no dots!
Command chainstake	  2	  	  pills	  of	  	  chloroquinine	  	  after	  	  6	  hours                                       ...
Command chains	  	  	  	  (	  ).	  	  	  	  	  (	  	  ).	  	  	  	  	  	  	  	  	  	  	  	  	  	  (	  	  	  	  	  ).	  (	 ...
Command chains                 9
Command chains  //	  methods	  with	  multiple	  arguments	  (commas)                                                     ...
Command chains  //	  methods	  with	  multiple	  arguments	  (commas)  take	  coffee	  	  with	  sugar,	  milk	  	  and	  ...
Command chains  //	  methods	  with	  multiple	  arguments	  (commas)  take	  coffee	  	  with	  sugar,	  milk	  	  and	  ...
Command chains  //	  methods	  with	  multiple	  arguments	  (commas)  take	  coffee	  	  with	  sugar,	  milk	  	  and	  ...
Command chains  //	  methods	  with	  multiple	  arguments	  (commas)  take	  coffee	  	  with	  sugar,	  milk	  	  and	  ...
Command chains  //	  methods	  with	  multiple	  arguments	  (commas)  take	  coffee	  	  with	  sugar,	  milk	  	  and	  ...
Command chains  //	  methods	  with	  multiple	  arguments	  (commas)  take	  coffee	  	  with	  sugar,	  milk	  	  and	  ...
Command chains  //	  methods	  with	  multiple	  arguments	  (commas)  take	  coffee	  	  with	  sugar,	  milk	  	  and	  ...
Command chains  //	  methods	  with	  multiple	  arguments	  (commas)  take	  coffee	  	  with	  sugar,	  milk	  	  and	  ...
Command chains  //	  methods	  with	  multiple	  arguments	  (commas)  take	  coffee	  	  with	  sugar,	  milk	  	  and	  ...
Command chains  //	  methods	  with	  multiple	  arguments	  (commas)  take	  coffee	  	  with	  sugar,	  milk	  	  and	  ...
Command chains  //	  methods	  with	  multiple	  arguments	  (commas)  take	  coffee	  	  with	  sugar,	  milk	  	  and	  ...
Command chains  //	  methods	  with	  multiple	  arguments	  (commas)  take	  coffee	  	  with	  sugar,	  milk	  	  and	  ...
Command chains  //	  methods	  with	  multiple	  arguments	  (commas)  take	  coffee	  	  with	  sugar,	  milk	  	  and	  ...
Command chains  //	  methods	  with	  multiple	  arguments	  (commas)  take	  coffee	  	  with	  sugar,	  milk	  	  and	  ...
GPars bundled•   GPars is bundled in the Groovy distribution•   GPars covers a wide range of parallel    and concurrent pa...
Closure enhancements• Closure annotation parameters•   Some more functional flavor    •composition: compose several closure...
Closure annotation parameters       @Retention(RetentionPolicy.RUNTIME)       @interface	  Invariant	  {	  	  	  	        ...
Closure annotation parameters       @Retention(RetentionPolicy.RUNTIME)       @interface	  Invariant	  {	  	  	  	        ...
Closure memoization                      13
Closure memoization     def	  plus	  =	  {	  a,	  b	  -­‐>	  sleep	  1000;	  a	  +	  b	  }.memoize()                      ...
Closure memoization     def	  plus	  =	  {	  a,	  b	  -­‐>	  sleep	  1000;	  a	  +	  b	  }.memoize()     assert	  plus(1,	...
Closure memoization     def	  plus	  =	  {	  a,	  b	  -­‐>	  sleep	  1000;	  a	  +	  b	  }.memoize()     assert	  plus(1,	...
Closure memoization     def	  plus	  =	  {	  a,	  b	  -­‐>	  sleep	  1000;	  a	  +	  b	  }.memoize()     assert	  plus(1,	...
Closure memoization     def	  plus	  =	  {	  a,	  b	  -­‐>	  sleep	  1000;	  a	  +	  b	  }.memoize()     assert	  plus(1,	...
Closure memoization     def	  plus	  =	  {	  a,	  b	  -­‐>	  sleep	  1000;	  a	  +	  b	  }.memoize()     assert	  plus(1,	...
Closure memoization     def	  plus	  =	  {	  a,	  b	  -­‐>	  sleep	  1000;	  a	  +	  b	  }.memoize()     assert	  plus(1,	...
Closure memoization     def	  plus	  =	  {	  a,	  b	  -­‐>	  sleep	  1000;	  a	  +	  b	  }.memoize()     assert	  plus(1,	...
Closure memoization     def	  plus	  =	  {	  a,	  b	  -­‐>	  sleep	  1000;	  a	  +	  b	  }.memoize()     assert	  plus(1,	...
Closure memoization     def	  plus	  =	  {	  a,	  b	  -­‐>	  sleep	  1000;	  a	  +	  b	  }.memoize()     assert	  plus(1,	...
Closure memoization     def	  plus	  =	  {	  a,	  b	  -­‐>	  sleep	  1000;	  a	  +	  b	  }.memoize()     assert	  plus(1,	...
Closure memoization     def	  plus	  =	  {	  a,	  b	  -­‐>	  sleep	  1000;	  a	  +	  b	  }.memoize()     assert	  plus(1,	...
Closure memoization     def	  plus	  =	  {	  a,	  b	  -­‐>	  sleep	  1000;	  a	  +	  b	  }.memoize()     assert	  plus(1,	...
Builtin JSON support•   Consuming•   Producing•   Pretty-printing                       14
Builtin JSON support   import	  groovy.json.*	     def	  payload	  =	  new	  URL(   	  	  	  	  "http://github.../json/com...
Builtin JSON support import	  groovy.json.*	   	   def	  json	  =	  new	  JsonBuilder()	   	   json.person	  {	  	  	  	  ...
Builtin JSON support import	  groovy.json.*	   	   def	  json	  =	  new	  JsonBuilder()	   	                              ...
Builtin JSON support   import	  groovy.json.*	     	     println	  JsonOutput.prettyPrint(   	  	  	  	  {"person":{"name"...
New AST transformations•   @Log                      •   Controlling execution                                  •   @Threa...
@Log•   Four different loggers can be injected   import	  groovy.util.logging.*	      •@Log                               ...
@Log•   Four different loggers can be injected     import	  groovy.util.logging.*	      •@Log                             ...
Controlling code execution•   Your application may run user’s code    •what if the code runs in infinite loops or for too l...
@ThreadInterrupt     @ThreadInterrupt     import	  groovy.transform.ThreadInterrupt	       	       while	  (true)	  {     ...
@ThreadInterrupt       @ThreadInterrupt       import	  groovy.transform.ThreadInterrupt	         	         while	  (true)	...
@ToString•       Provides a default toString() method to your types•       Available annotation options    •    includeNam...
@EqualsAndHashCode•   Provides default implementations for equals() and hashCode() methods                    import	  gro...
@TupleConstructor•   Provides a «classical» constructor with all properties•   Several annotation parameter options availa...
@InheritConstructors•   Classes like Exception are painful when extended,    as all the base constructors should be replic...
@InheritConstructors•   Classes like Exception are painful when extended,    as all the base constructors should be replic...
Miscelanous•   Compilation customizers•   Java 7 diamond operator•   Slashy and dollar slashy strings•   New GDK methods• ...
Compilation customizers•   Ability to apply some customization    to the Groovy compilation process•   Three available cus...
Imports customizer    def	  configuration	  =	  new	  CompilerConfiguration()    	      def	  custo	  =	  new	  ImportCust...
What’scookingfor 2.0?
Groovy 2.0 roadmap•   Towards a more modular Groovy•   Java 7 alignements: Project Coin    • binary literals    • undersco...
Groovy Modularity•   Groovy’s «all» JAR weighs in at 4MB• Nobody needs everything • Template engine, Ant scripting, Swing ...
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 representa...
Underscore in literals•   Now we can also add underscores in number literals for more readability         long	  creditCar...
Multicatch•   One block for multiple exception caught    •rather than duplicating the block         try	  {         	  	  ...
InvokeDynamic• Groovy 2.0 supports JDK 7’s invokeDynamic • compiler has a flag for compiling against JDK 7 • might use the ...
Static Type Checking•       Goal: make the Groovy compiler «grumpy»!    •    and throw compilation errors (not at runtime)...
Typos in your vars or methodsimport	  groovy.transform.TypeChecked	  void	  method()	  {}	  @TypeChecked	  test()	  {	  	 ...
Typos in your vars or methodsimport	  groovy.transform.TypeChecked	  void	  method()	  {}	  @TypeChecked	  test()	  {	  	 ...
Typos in your vars or methodsimport	  groovy.transform.TypeChecked                             Annotation can be at	      ...
Complain on wrong assignments   //	  cannot	  assign	  value	  of	  type...	  to	  variable...   int	  x	  =	  new	  Objec...
Complain on wrong assignments   //	  cannot	  assign	  value	  of	  type...	  to	  variable...   int	  x	  =	  new	  Objec...
Complain on wrong return types     //	  checks	  if/else	  branch	  return	  values     @TypeChecked     int	  method()	  ...
Complain on wrong return types     //	  checks	  if/else	  branch	  return	  values     @TypeChecked     int	  method()	  ...
Type inference      @TypeChecked	  test()	  {      	  	  	  	  def	  name	  =	  "	  	  Guillaume	  	  "      	        	  	...
Statically checked & dynamic methods         @TypeChecked         String	  greeting(String	  name)	  {         	  	  	  	 ...
Instanceof checks      @TypeChecked	        void	  test(Object	  val)	  {      	  	  	  	  if	  (val	  instanceof	  String...
Instanceof checks      @TypeChecked	                                                                                No nee...
Instanceof checks      @TypeChecked	                                                                                No nee...
Lowest Upper Bound•   Represents the lowest «super» type that classes have in common    •may be virtual (aka «non-denotabl...
Lowest Upper Bound•   Represents the lowest «super» type that classes have in common    •may be virtual (aka «non-denotabl...
Flow typing•   Static type checking shouldn’t complain even for bad coding practicies which work    without type checks   ...
Gotchas: static checking vs dynamic•   Type checking works at compile-time    • adding @TypeChecked doesn’t change behavio...
Gotchas: runtime metaprogramming     @TypeChecked	       void	  test()	  {     	  	  	  	  Integer.metaClass.foo	  =	  {} ...
Gotchas: runtime metaprogramming     @TypeChecked	       void	  test()	  {     	  	  	  	  Integer.metaClass.foo	  =	  {} ...
Gotchas: runtime metaprogramming     @TypeChecked	       void	  test()	  {     	  	  	  	  Integer.metaClass.foo	  =	  {} ...
Gotchas: closures need explicit types         @TypeChecked	  test()	  {         	  	  	  	  ["a",	  "b",	  "c"].collect	  ...
Gotchas: closures need explicit types         @TypeChecked	  test()	  {         	  	  	  	  ["a",	  "b",	  "c"].collect	  ...
Closure shared variables          @TypeChecked	  test()	  {          	  	  	  	  def	  var	  =	  "abc"	  	  	  	  	  	  	 ...
Closure shared variables                                  var assigned in the closure:                                    ...
Closure shared variables                                      var assigned in the closure:                                ...
Closure shared variables                                      var assigned in the closure:                                ...
Closure shared variables        class	  A	  	  	  	  	  	  	  	  	  	  	  {	  void	  foo()	  {}	  }        class	  B	  ext...
Closure shared variables        class	  A	  	  	  	  	  	  	  	  	  	  	  {	  void	  foo()	  {}	  }        class	  B	  ext...
Static Compilation•   Given your Groovy code can be type checked...    we can as well compile it «statically»    •   ie. g...
Static Compilation: advantages•    You gain:    • Type safety     •  thanks to static type checking          •          st...
Static Compilation: advantages•    You gain:    • Type safety     •  thanks to static type checking          •          st...
Static Compilation: disadvantages•   But you loose:    •   Dynamic features        •metaclass changes, categories, etc.   ...
Statically compiled & dynamic methods         @CompileStatic         String	  greeting(String	  name)	  {         	  	  	 ...
What about performance?•   Comparisons between:    •   Java    •   Groovy static compilation (Groovy 2.0)    •   Groovy wi...
What about performance?                              Fibonacci   Pi (π) quadrature   Binary trees                  Java   ...
Summary•   Main themes of the Groovy 2.0 release    •Modularity    •   Embark the JDK 7 enhancements        •Project Coin ...
Summary          ROCKS!               58
59
Thank you!                                  ge                       me    Lafor lopment             Guillau roovy Deve   ...
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/galler...
Upcoming SlideShare
Loading in...5
×

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

1,483

Published on

Update on the key features of 1.8 and the upcoming 2.0.

Published in: Technology, Business
0 Comments
2 Likes
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total Views
1,483
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
25
Comments
0
Likes
2
Embeds 0
No embeds

No notes for slide

Transcript of "Groovy 2.0 update - Cloud Foundry Open Tour Moscow - Guillaume Laforge"

  1. 1. Groovy 2.0What’s up, Doc? Guillaume Laforge Groovy Project Manager SpringSource / VMware @glaforge 1
  2. 2. Groovy 2.0What’s up, Doc? Guillaume Laforge Groovy Project Manager SpringSource / VMware @glaforge 1
  3. 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. 4. 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
  5. 5. 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
  6. 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. 7. Command chains  turn  left    then  right   6
  8. 8. Command chains Alternation of method names  turn  left    then  right   6
  9. 9. Command chains Alternation of method names  turn  left    then  right   and parameters (even named ones) 6
  10. 10. Command chains  turn  left    then  right   6
  11. 11. Command chains Equivalent to:          (        ).        (          )  turn  left    then  right   6
  12. 12. Look Ma!No par ens, no dots!
  13. 13. Command chainstake  2    pills  of    chloroquinine    after    6  hours 8
  14. 14. Command chains        (  ).          (    ).                            (          ).  (          )take  2    pills  of    chloroquinine    after    6  hours 8
  15. 15. Command chains 9
  16. 16. Command chains //  methods  with  multiple  arguments  (commas) 9
  17. 17. Command chains //  methods  with  multiple  arguments  (commas) take  coffee    with  sugar,  milk    and  liquor 9
  18. 18. Command chains //  methods  with  multiple  arguments  (commas) take  coffee    with  sugar,  milk    and  liquor //  leverage  named-­‐args  as  punctuation 9
  19. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 32. 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
  33. 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. 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. 35. Closure memoization 13
  36. 36. Closure memoization def  plus  =  {  a,  b  -­‐>  sleep  1000;  a  +  b  }.memoize() 13
  37. 37. Closure memoization def  plus  =  {  a,  b  -­‐>  sleep  1000;  a  +  b  }.memoize() assert  plus(1,  2)  ==  3  //  after  1000ms 13
  38. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 49. Builtin JSON support• Consuming• Producing• Pretty-printing 14
  50. 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. 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. 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. 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. 54. New AST transformations• @Log • Controlling execution • @ThreadInterrupt• @Field • @TimedInterrupt • @ConditionalInterrupt• @AutoClone • @InheritConstructor• @AutoExternalizable • @WithReadLock• @Canonical • @WithWriteLock • @ToString • @EqualsAndHashCode • @TupleConstructor • @ListenerList 18
  55. 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. 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. 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. 58. @ThreadInterrupt @ThreadInterrupt import  groovy.transform.ThreadInterrupt     while  (true)  {        //  eat  lots  of  CPU } 21 33
  59. 59. @ThreadInterrupt @ThreadInterrupt import  groovy.transform.ThreadInterrupt     while  (true)  { {        if  (Thread.currentThread.isInterrupted())                throw  new  InterruptedException() }        //  eat  lots  of  CPU } 21 33
  60. 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. 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. 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. 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. 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. 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. 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. 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. 68. What’scookingfor 2.0?
  69. 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. 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. 71. Java 7 / JDK 7• Project Coin and InvokeDynamic 32
  72. 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. 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. 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. 75. 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
  76. 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. 77. Typos in your vars or methodsimport  groovy.transform.TypeChecked  void  method()  {}  @TypeChecked  test()  {        //  Cannot  find  matching  method  metthhoood()        metthhoood()          def  name  =  "Guillaume"        //  variable  naamme  is  undeclared        println  naamme} 38
  78. 78. Typos in your vars or methodsimport  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. 79. Typos in your vars or methodsimport  groovy.transform.TypeChecked Annotation can be at   class or method levelvoid  method()  {}  @TypeChecked  test()  {        //  Cannot  find  matching  method  metthhoood()        metthhoood()   Compilation        def  name  =  "Guillaume" errors!        //  variable  naamme  is  undeclared        println  naamme} 38
  80. 80. 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
  81. 81. 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
  82. 82. 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
  83. 83. 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
  84. 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. 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. 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. 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. 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. 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. 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. 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. 92. 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
  93. 93. Gotchas: runtime metaprogramming @TypeChecked   void  test()  {        Integer.metaClass.foo  =  {}        123.foo() } 47
  94. 94. Gotchas: runtime metaprogramming @TypeChecked   void  test()  {        Integer.metaClass.foo  =  {}        123.foo() } Not allowed: metaClass property is dynamic 47
  95. 95. Gotchas: runtime metaprogramming @TypeChecked   void  test()  {        Integer.metaClass.foo  =  {}        123.foo() } Method not Not allowed: recognized metaClass property is dynamic 47
  96. 96. Gotchas: closures need explicit types @TypeChecked  test()  {        ["a",  "b",  "c"].collect  {                it.toUpperCase()  //  Not  OK        } }• A «Groovy Enhancement Proposal» to address this issue 48
  97. 97. 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
  98. 98. Closure shared variables @TypeChecked  test()  {        def  var  =  "abc"                      def  cl  =  {  var  =  new  Date()  }        cl()        var.toUpperCase()    //  Not  OK! } 49
  99. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 110. What about performance? Fibonacci Pi (π) quadrature Binary trees Java 143 ms 93 ms 4.5 s Static1.7 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. 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. 112. Summary ROCKS! 58
  113. 113. 59
  114. 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. 115. Questions & Answers• Got questions, really? Q&A 61
  116. 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
  1. A particular slide catching your eye?

    Clipping is a handy way to collect important slides you want to go back to later.

×