Groovy, State of the Union - Groovy Grails eXchange 2010 - Guillaume Laforge

jeudi 16 décembre 2010

State of the Unionjeudi 16 décembre 2010

Copyright 2010 SpringSource. Copying, publishing or distributing without express written permission is prohibited.

Guillaume Laforge / @glaforge

• Groovy Project Manager• Head of Groovy Development

at SpringSource• Initiator of the Grails framework• Founder of the Gaelyk toolkit• Co-author of Groovy in Action• Member of «Les Cast Codeurs» podcast

• Speaker: JavaOne, QCon, JavaZone, Sun TechDays, Devoxx, The Spring Experience, SpringOne2GX, JAX, Dynamic Language World, IJTC, and more...

2jeudi 16 décembre 2010


Agenda

•Past–Groovy 1.6 flashback

•Present–Groovy 1.7 novelties–A few Groovy 1.7.x refinements

•Future–What’s cooking for 1.8 and beyond



But first... some figures...

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Groovy downloads per monthDownloads Moving Average (year)




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Groovy 1.5

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Groovy 1.5

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Groovy 1.6




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Groovy 1.7




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Groovy 1.6

Groovy 1.7

185Kjeudi 16 décembre 2010


Groovy 1.7.6 and 1.8-beta-3


looking into the Pastjeudi 16 décembre 2010


Big highlights of Groovy 1.6

• Greater compile-time and runtime performance• Multiple assignments• Optional return for if/else and try/catch/finally• Java 5 annotation definition• AST Transformations• The Grape module and dependency system• Various Swing related improvements• JMX Builder• Metaprogramming additions• JSR-223 scripting engine built-in• Out-of-the-box OSGi support




• Greater compile-time and runtime performance• Multiple assignments• Optional return for if/else and try/catch/finally• Java 5 annotation definition• AST Transformations• The Grape module and dependency system• Various Swing related improvements• JMX Builder• Metaprogramming additions• JSR-223 scripting engine built-in• Out-of-the-box OSGi support



Multiple assignement

// multiple assignmentdef (a, b) = [1, 2]assert a == 1 && b == 2

// with typed variablesdef (int c, String d) = [3, "Hi"]assert c == 3 && d == "Hi"

def geocode(String place) { [48.8, 2.3] }def lat, lng// assignment to existing variables(lat, lng) = geocode('Paris')

// classical variable swaping example(a, b) = [b, a]



More optional return

// optional return for if statements

def m1() { if (true) 1 else 0}assert m1() == 1

// optional return for try/catch/finally

def m2(bool) { try { if (bool) throw new Exception()

1 } catch (any) { 2 } finally { 3 }}assert m2(true) == 2 && m2(false) == 1



AST Transformation (1/2)

• Groovy 1.6 introduced AST Transformations–AST: Abstract Syntax Tree

• Ability to change what’s being compiled by the Groovy compiler... at compile time–No runtime impact!–Change the semantics of your programs! Even hijack the

Groovy syntax!–Implementing recurring patterns in your code base–Remove boiler-plate code

• Two kinds: global and local–triggered by annotations



AST Transformations (2/2)

• Transformations introduced in 1.6–@Singleton–@Immutable, @Lazy, @Delegate–@Newify–@Category, @Mixin–@PackageScope–Swing’s @Bindable and @Vetoable–Grape’s own @Grab



@Immutable

• To properly implement immutable classes–No mutations — state musn’t change–Private final fields–Defensive copying of mutable components–Proper equals() / hashCode() / toString()

for comparisons or as keys in maps

@Immutable class Coordinates { Double lat, lng}def c1 = new Coordinates(lat: 48.8, lng: 2.5)

def c2 = new Coordinates(48.8, 2.5)assert c1 == c2



Grab a grape!

• Simple distribution and sharing of Groovy scripts• Dependencies stored locally

–Can even use your own local repositories

@Grab(group = 'org.mortbay.jetty',

module = 'jetty‐embedded',

version = '6.1.0')

def startServer() { def srv = new Server(8080)

def ctx = new Context(srv , "/", SESSIONS)

ctx.resourceBase = "."

ctx.addServlet(GroovyServlet, "*.groovy")

srv.start()}


into the Present...jeudi 16 décembre 2010



• Anonymous Inner Classes and Nested Classes• Annotations anywhere• Grape improvements• Power Asserts• AST Viewer• AST Builder• Customize the Groovy Truth!• Rewrite of the GroovyScriptEngine• Groovy Console improvements• SQL support refinements



AIC and NC

• Anonymous Inner Classes and Nested Classes



AIC and NC

• Anonymous Inner Classes and Nested Classes

For Java

copy’n paste

compatibility

sake :-)



Annonymous Inner Classes

boolean called = false

Timer timer = new Timer()

timer.schedule(new TimerTask() {

void run() {

called = true

}}, 0)

sleep 100assert called



Annonymous Inner Classes

boolean called = false

Timer timer = new Timer()

timer.schedule(new TimerTask() {

void run() {

called = true

}}, 0)

sleep 100assert called

{ called = true } as TimerTask



Nested Classes

class Environment { static class Production extends Environment {}

static class Development extends Environment {}

}

new Environment.Production()



Anotations almost anywhere

• You can put annotations–on imports–on packages–on variable declarations

• Examples with @Grab following...



Grape improvements (1/4)

• @Grab on import

@Grab(group = 'net.sf.json‐lib',

module = 'json‐lib', version = '2.3', classifier = 'jdk15')import net.sf.json.groovy.*

assert new JsonSlurper().parseText(

new JsonGroovyBuilder().json {

book(title: "Groovy in Action",

author: "Dierk König et al")

}.toString()).book.title == "Groovy in Action"




• Shorter module / artifact / version parameter–Example of an annotation on a variable declaration

@Grab('net.sf.json‐lib:json‐lib:2.3:jdk15')

def builder = new net.sf.json.groovy.JsonGroovyBuilder()

def books = builder.books { book(title: "Groovy in Action", author: "Dierk Koenig")

}assert books.toString() == '{"books":{"book":{"title":"Groovy in Action",' +

'"author":"Dierk Koenig"}}}'




• Groovy 1.7 introduced Grab resolver–For when you need to specify a specific repository

for a given dependency

@GrabResolver( name = 'restlet.org', root = 'http://maven.restlet.org')

@Grab('org.restlet:org.restlet:1.1.6')

import org.restlet.Restlet


http://maven.restlet.org/












Power Asserts (1/2)

• Much better assert statement!–Invented and developed in the Spock framework

• Given this script...

def energy = 7200 * 10**15 + 1def mass = 80def celerity = 300000000

assert energy == mass * celerity ** 2



Power Asserts (2/2)

• You’ll get a more comprehensible output



Easier AST Transformations

• AST Transformations are a very powerful feature

• But are still rather hard to develop–Need to know the AST API closely

• To help with authoring your own transformations, we’ve introduced–the AST Viewer in the Groovy Console–the AST Builder



AST Viewer



AST Builder

// Ability to build AST parts

// ‐‐> from a Stringnew AstBuilder().buildFromString(''' "Hello" '''

)

// ‐‐> from codenew AstBuilder().buildFromCode { "Hello" }

// ‐‐> from a specification

List<ASTNode> nodes = new AstBuilder().buildFromSpec {

block { returnStatement {

constant "Hello"

} }}



Customize the Groovy Truth!

• Ability to customize the truth by implementing a boolean asBoolean() method

class Predicate { boolean value boolean asBoolean() { value }

}

def truePred = new Predicate(value: true)

def falsePred = new Predicate(value: false)

assert truePred && !falsePred



Groovy 1.7.x changes

• Since Groovy 1.7.0...Groovy 1.7.1, 1.7.2, 1.7.3, 1.7.4, 1.7.5 and 1.7.6 have been released already!

• Here’s what’s new!




• Groovy 1.7.5 even further shrinks the grab resolver definition:

32

@GrabResolver('http://maven.restlet.org')

@Grab('org.restlet:org.restlet:1.1.6')

import org.restlet.Restlet














Map improvements (1/2)

// map auto‐vificationdef m = [:].withDefault { key ‐> "Default" }

assert m['z'] == "Default"

assert m['a'] == "Default"

// default sort, sort with a comparator

m.sort()m.sort({ a, b ‐> a <=> b } as Comparator)

// max{} and min{}assert [a: 1, b: 2].max{ it.value }.value == 2




// before Map#withDefault()

def words = "one two two three three three".split()

def freq = [:]

words.each { if (it in freq) freq[it] += 1 else freq[it] = 1 }




// after Map#withDefault()

def words = "one two two three three three".split()

def freq = [:].withDefault { k ‐> 0 }

words.each {

freq[it] += 1

}



XML back to String

• Ability to retrieve the XML string from a node from an XmlSlurper GPathResult

def xml = """<books> <book isbn="12345">Groovy in Action</book>

</books>"""def root = new XmlSlurper().parseText(xml)

def someNode = root.bookdef builder = new StreamingMarkupBuilder()

assert builder.bindNode(someNode).toString() ==

"<book isbn='12345'>Groovy in Action</book>"



Currying improvements

// right curryingdef divide = { a, b ‐> a / b }

def halver = divide.rcurry(2)

assert halver(8) == 4 // currying n‐th parameterdef joinWithSeparator = { one, sep, two ‐>

one + sep + two}def joinWithComma = joinWithSeparator.ncurry(1, ', ')

assert joinWithComma('a', 'b') == 'a, b'



Date improvements

import static java.util.Calendar.*

// convert to calendardef cal = new Date().toCalendar()

// update a date (or a calendar)

cal.set(year: cal[YEAR] + 1)

cal[MONTH] = MARCH

// create a new date (or a calendar) from one

def nextYear = cal.updated(year: cal[YEAR] + 1)



New String methods

println """ def method() { return 'bar' }""".stripIndent()

println """ |def method() { | return 'bar' |}""".stripMargin('|')

// string "translation" (UNIX tr)

assert 'hello'.tr('z‐a', 'Z‐A') == 'HELLO'

assert 'Hello World!'.tr('a‐z', 'A') == 'HAAAA WAAAA!'

assert 'Hello World!'.tr('lloo', '1234') == 'He224 W4r2d!'

// capitalize the first letter

assert 'h'.capitalize() == 'H'

assert 'hello'.capitalize() == 'Hello'

assert 'hello world'.capitalize() == 'Hello world'

// tab/space (un)expansion (UNIX expand command)

assert '1234567\t8\t '.expand() == '1234567 8 '

assert ' x '.unexpand() == ' x\t '



Map supports isCase()

40

def m = [a: 1, b: 2]def val = 'a'

switch (val) { case m: "key in map"; break

// equivalent to // case { val in m }: ...

default: "not in map"}



(G)String to Enum coercion

41

enum Color { red, green, blue}

// coercion with asdef r = "red" as Color

// implicit coercionColor b = "blue"

// with GStrings toodef g = "${'green'}" as Color


...and beyond!jeudi 16 décembre 2010


Groovy 1.8 & beyond

• Still subject to discussion• Always evolving roadmap• Things may change!


What’s cooking?jeudi 16 décembre 2010


What we’re working on

• More runtime performance improvements• Closures

–annotation parameterscomposition, memoization, and trampoline

• Native JSON support–builder and parser

• New AST transformations• Gradle build• Modularizing Groovy• Align with JDK 7 / Java 7 / Project Coin• Enhanced DSL support


G



An example, with Fibonacci




• Known example of worst case performance for Groovy





• Groovy 1.7.5 vs Java–25131ms / 1110ms –22x slower!






• Groovy 1.8-beta-3 vs Java–1871ms / 1110ms–only 68% slower






• Groovy 1.8-beta-3 vs Java–1871ms / 1110ms–only 68% slower

48

13xjeudi 16 décembre 2010


Optimizations for int

• Currently, the optimizations cover most of native operations on primitive ints–Be careful, your mileage may vary

• To come next–optimizations for doubles–improving array accesses–then other primitives optimizations–and mixed cases of primitives



Closure annotation parameters

• Groovy 1.5 brought Java 5 annotations

• What if... we could go beyond what Java offered?–In 1.7, we can put annotations on packages, imports and

variable declarations–But annotations are still limited in terms of parameters

they allow

• Here comes closure annotation parameters!–Groovy 1.8 will give us the ability to access annotation

with closure parameters at runtime



GContracts

• Closures are already allowed in the Groovy 1.7 Antlr grammar–André Steingreß created GContracts,

a «design by contract» module

// a class invariant@Invariant({ name.size() > 0 && age > ageLimit() })

class Person { String name; int age }

// a method pre‐condition@Requires({ message != null })void greet(String message) { ... }

// a method post‐condition@Ensures({ returnResult % 2 == 0 })

int evenResult() { ... }



Closure composition

• Functional flavor!

52

def plus2 = { it + 2 }def times3 = { it * 3 } def composed1 = plus2 << times3assert composed1(3) == 11assert composed1(4) == plus2(times3(4))

def composed2 = times3 << plus2assert composed2(3) == 15assert composed2(5) == times3(plus2(5))

// reverse compositionassert composed1(3) == (times3 >> plus2)(3)



Closure memoization

• Memoization: remember the outcome of previous (ideally side-effect free) invocations

53

def c = { a, b ‐> sleep 1000; a + b }.memoize()

assert c(1, 2) == 3 // after 1000ms

assert c(1, 2) == 3 // return immediately

// other forms:// at least 10 invocations cached

def cAtLeast = { ... }.memoizeAtLeast(10)

// at most 10 invocations cacheddef cAtMost = { ... }.memoizeAtMost(10)

// between 10 and 20 invocations cached

def cAtLeast = { ... }.memoizeBetween(10, 20)



Closure trampoline

• No more infamous StackOvervlow errors for deeply recursive algorithms–if you use closure trampolines explicitely

54

def factfact = { int n, BigInteger accu ‐>

n > 1 ? fact.trampoline(n ‐ 1, n * accu) : accu

}.trampoline()

def factorial = { int n ‐> fact(n, 1G) }

assert factorial(1) == 1assert factorial(3) == 6assert factorial(1000) == 402387260077...



New AST xforms (1/2)

• Many new transformations coming up for removing even more boiler plate code

55

@Log inject a logger in your classes@Field creates a field in your scripts@PackageScope improvements (methods & fields)@Synchronized providing safer synchronization semantics@InheritConstructor ex. when extending Exception@IndexedProperties JavaBeans indexed property support@AutoClone automatic cloning of your beans@AutoExternalizable automatic externalization of your beans



New AST xforms (2/2)

56

@ThreadInterrupt makes a script interruptible@TimedInterrupt interrupt after a period of time@ConditionalInterrupt interrupt with a custom condition

@Canonical adds equals, hashCode, toString, ctor- @EqualsAndHashCode just equals and hashCode- @ToString just toString- @TupleConstructor adds a «tuple» constructor



Java 7 / 8 / Project Coin

• Alignment with JDK 7 will come in Groovy 1.9• JSR-292 InvokeDynamic• Simple Closures (8)

• Proposals from Project Coin–Strings in switch (7)–Automatic Resource Management (7)–Improved generics type inference (diamond <>) (7)–Simplified varargs method invocation (7)–Better integral literals (7)–Language support for collections (8?)



Improved DSL support

• GEP-3: an extended command expression DSL–Groovy Extension Proposal #3

• Command expressions–basically top-level statements without parens–combine named and non-named arguments in the mix

•for nicer Domain-Specific Languages–(methodName arguments)*



Before GEP-3

• The idea: extend command-expressions, beyond top-level statements, for chained method calls

• Before

send("Hello").to("Graeme")

check(that: margherita).tastes(good)

sell(100.shares).of(MSFT)

take(2.pills).of(chloroquinine).after(6.hours)

wait(10.minutes).and(execute { })

blend(red, green).of(acrylic)



With GEP-3


• After

send "Hello" to "Graeme"

check that: margherita tastes good

sell 100.shares of MSFT

take 2.pills of chloroquinine after 6.hours

wait 10.minutes and execute { }

blend red, green of acrylic



With GEP-3


• After

send "Hello" to "Graeme"


sell 100.shares of MSFT

take 2.pills of chloroquinine after 6.hours

wait 10.minutes and execute { }

blend red, green of acrylic

Less parens& commas



The pattern

• A repetition of–method name–arguments (mix of named and normal)

61


methodname

methodname

parameternamed parameter



Summary

• No need to wait for Java 7, 8, 9...–closures, properties, interpolated strings, extended

annotations, metaprogramming, [YOU NAME IT]...



Summary

• No need to wait for Java 7, 8, 9...–closures, properties, interpolated strings, extended

annotations, metaprogramming, [YOU NAME IT]...

Groovy’s still

innovative

since 2003!



Q and A



Picture credits

Myself http://www.flickr.com/photos/romainguy/783719255/sizes/l/in/photostream/Big hat http://cdn.plussizecostumesupercenter.com/csc_inc/images/items/343x432/47703.jpgRIP http://gipsydan.files.wordpress.com/2009/11/rip.jpgHouse / past: http://www.flickr.com/photos/jasonepowell/3680030831/sizes/o/Present clock: http://www.flickr.com/photos/38629278@N04/3784344944/sizes/o/Future: http://www.flickr.com/photos/befuddledsenses/2904000882/sizes/l/Cooking: http://www.flickr.com/photos/eole/449958332/sizes/l/Snail http://www.freakingnews.com/images/app_images/snail-0.jpgUsein bolt record http://www.phombo.com/sports/usain-bolt-beijing-2008-olympics/17450/full/popular/Fibonacci figure http://cnx.org/content/m22060/latest/graphics1.jpgFibonacci face http://www.robinkelly.co.nz/site/acupil/images/lfib.jpgPuzzle: http://www.everystockphoto.com/photo.php?imageId=263521Light bulb: https://newsline.llnl.gov/retooling/mar/03.28.08_images/lightBulb.pngCheck mark: http://www.lnl.infn.it/~epics/WikiDumps/localhost/600px-symbol_ok.svg.pngPuzzle: http://www.everystockphoto.com/photo.php?imageId=263521Light bulb: https://newsline.llnl.gov/retooling/mar/03.28.08_images/lightBulb.pngGreen leaf: http://www.flickr.com/photos/epsos/3384297473/Trafic light: http://rihancompany.com/var/243/35581-Traffic%20light%20drawing.jpgButt kick: http://www.brentcsutoras.com/wp-content/uploads/2009/12/kick-ass-1.jpg


http://www.flickr.com/photos/romainguy/783719255/sizes/l/in/photostream/

http://www.flickr.com/photos/romainguy/783719255/sizes/l/in/photostream/

http://cdn.plussizecostumesupercenter.com/csc_inc/images/items/343x432/47703.jpg

http://cdn.plussizecostumesupercenter.com/csc_inc/images/items/343x432/47703.jpg

http://gipsydan.files.wordpress.com/2009/11/rip.jpg

http://gipsydan.files.wordpress.com/2009/11/rip.jpg

http://www.flickr.com/photos/jasonepowell/3680030831/sizes/o/

http://www.flickr.com/photos/jasonepowell/3680030831/sizes/o/

http://www.flickr.com/photos/38629278@N04/3784344944/sizes/o/

http://www.flickr.com/photos/38629278@N04/3784344944/sizes/o/

http://www.flickr.com/photos/befuddledsenses/2904000882/sizes/l/

http://www.flickr.com/photos/befuddledsenses/2904000882/sizes/l/

http://www.flickr.com/photos/eole/449958332/sizes/l/

http://www.flickr.com/photos/eole/449958332/sizes/l/

http://www.freakingnews.com/images/app_images/snail-0.jpg

http://www.freakingnews.com/images/app_images/snail-0.jpg

http://www.phombo.com/sports/usain-bolt-beijing-2008-olympics/17450/full/popular/

http://www.phombo.com/sports/usain-bolt-beijing-2008-olympics/17450/full/popular/

http://cnx.org/content/m22060/latest/graphics1.jpg

http://cnx.org/content/m22060/latest/graphics1.jpg

http://www.robinkelly.co.nz/site/acupil/images/lfib.jpg

http://www.robinkelly.co.nz/site/acupil/images/lfib.jpg

http://www.everystockphoto.com/photo.php?imageId=263521


https://newsline.llnl.gov/retooling/mar/03.28.08_images/lightBulb.png


http://www.lnl.infn.it/~epics/WikiDumps/localhost/600px-symbol_ok.svg.png

http://www.lnl.infn.it/~epics/WikiDumps/localhost/600px-symbol_ok.svg.png





http://www.flickr.com/photos/epsos/3384297473/

http://www.flickr.com/photos/epsos/3384297473/

http://rihancompany.com/var/243/35581-Traffic%20light%20drawing.jpg

http://rihancompany.com/var/243/35581-Traffic%20light%20drawing.jpg

http://www.brentcsutoras.com/wp-content/uploads/2009/12/kick-ass-1.jpg

http://www.brentcsutoras.com/wp-content/uploads/2009/12/kick-ass-1.jpg

Groovy, State of the Union - Groovy Grails eXchange 2010 - Guillaume Laforge

Technology

Transcript of Groovy, State of the Union - Groovy Grails eXchange 2010 - Guillaume Laforge