groovy in 2014 and beyond
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© 2014 SpringOne 2GX. All rights reserved. Do not distribute without permission.
Groovy, in 2014 and beyondGuillaume Laforge — Groovy project lead / Pivotal
@glaforge
Stay up-to-date
Groovy Weekly Newsletter (Every Tuesday) http://beta.groovy-lang.org/groovy-weekly.html
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© 2014 SpringOne 2GX. All rights reserved. Do not distribute without permission.
Agenda
The Groovy roadmap
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2015 20142013
Groovy 2.3
Groovy 2.4Groovy 2.2
Groovy 2.5 ?
Groovy 3.0 ?
Groovy 2.3
• JDK 8 runtime support • Traits • New and updates AST transformations • NIO2 module • JSON improvements & performance gains • New Markup template engine • Documentation overhaul
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Groovy 2.4
• Android support !
• New website !
• Potentially • Macro system? • New grammar?
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Groovy 3.0
• New Meta-Object Protocol !
• Invoke-dynamic based runtime !
• Rewritten language grammar with Antlr v4 • unless re-scheduled for Groovy 2.4 • successful GSoC, but not fully complete coverage
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© 2014 SpringOne 2GX. All rights reserved. Do not distribute without permission.
Groovy 2.3
© 2014 SpringOne 2GX. All rights reserved. Do not distribute without permission.
JDK 8 support
JDK 8 support — closures vs lambdas
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IntStream.range(1, 100).forEach(s -‐> System.out.println(s)); !Files.lines(Paths.get('README.adoc')) .map(it -‐> it.toUpperCase()) .forEach(it -‐> System.out.println(it));
JDK 8 support — closures vs lambdas
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IntStream.range(1, 100).forEach(s -‐> System.out.println(s)); !Files.lines(Paths.get('README.adoc')) .map(it -‐> it.toUpperCase()) .forEach(it -‐> System.out.println(it));
IntStream.range(1, 100).forEach { println it } !Files.lines(Paths.get('README.adoc')) .map { it.toUpperCase() } .forEach { println it }
JDK 8 support — closures vs lambdas
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IntStream.range(1, 100).forEach(s -‐> System.out.println(s)); !Files.lines(Paths.get('README.adoc')) .map(it -‐> it.toUpperCase()) .forEach(it -‐> System.out.println(it));
IntStream.range(1, 100).forEach { println it } !Files.lines(Paths.get('README.adoc')) .map { it.toUpperCase() } .forEach { println it }
Use Groovy closureswherever you passlambdas in Java 8
To know all about AST transformations!
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Groovy in the light of Java 8 by Guillaume Laforge Tue 12:45pm / F. Park 1
© 2014 SpringOne 2GX. All rights reserved. Do not distribute without permission.
Traits
Traits
• Like interfaces, but with method bodies • similar to Java 8 interface default methods
• Elegant way to compose behavior • multiple inheritance without the « diamond » problem
• Traits can also be stateful • traits can have properties like normal classes
• Compatible with static typing and static compilation • class methods from traits also visible from Java classes
• Also possible to implement traits at runtime 15
Traits: a simple example
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trait FlyingAbility { String fly() { "I'm flying!" } } !
class Bird implements FlyingAbility {} def b = new Bird() !
assert b.fly() == "I'm flying!"
Traits: a simple example
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trait FlyingAbility { String fly() { "I'm flying!" } } !
class Bird implements FlyingAbility {} def b = new Bird() !
assert b.fly() == "I'm flying!"
« trait », a new keyword for a new concept
Traits: a simple example
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trait FlyingAbility { String fly() { "I'm flying!" } } !
class Bird implements FlyingAbility {} def b = new Bird() !
assert b.fly() == "I'm flying!"
a class « implements »
a trait
Traits: a simple example
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trait FlyingAbility { String fly() { "I'm flying!" } } !
class Bird implements FlyingAbility {} def b = new Bird() !
assert b.fly() == "I'm flying!"
the fly() method from the trait is available
Traits: a simple example
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trait FlyingAbility { String fly() { "I'm flying!" } } !
class Bird implements FlyingAbility {} def b = new Bird() !
assert b.fly() == "I'm flying!"
Traits: stateful
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trait Named { String name } !
class Bird implements Named {} def b = new Bird(name: 'Colibri') !
assert b.name == 'Colibri'
Traits: stateful
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trait Named { String name } !
class Bird implements Named {} def b = new Bird(name: 'Colibri') !
assert b.name == 'Colibri'
a Groovy property
Traits: stateful
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trait Named { String name } !
class Bird implements Named {} def b = new Bird(name: 'Colibri') !
assert b.name == 'Colibri'
implement the trait
Traits: stateful
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trait Named { String name } !
class Bird implements Named {} def b = new Bird(name: 'Colibri') !
assert b.name == 'Colibri'
Groovy named argument constructor
Traits: stateful
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trait Named { String name } !
class Bird implements Named {} def b = new Bird(name: 'Colibri') !
assert b.name == 'Colibri'
access the property
Traits: stateful
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trait Named { String name } !
class Bird implements Named {} def b = new Bird(name: 'Colibri') !
assert b.name == 'Colibri'
Traits: inheritance
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trait Named { String name } !
trait FlyingAbility extends Named { String fly() { "I'm a flying ${name}!" } } !
class Bird implements FlyingAbility {} def b = new Bird(name: 'Colibri') !
assert b.name == 'Colibri' assert b.fly() == "I'm a flying Colibri!"
Traits: inheritance
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trait Named { String name } !
trait FlyingAbility extends Named { String fly() { "I'm a flying ${name}!" } } !
class Bird implements FlyingAbility {} def b = new Bird(name: 'Colibri') !
assert b.name == 'Colibri' assert b.fly() == "I'm a flying Colibri!"
extend the Named trait
Traits: inheritance
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trait Named { String name } !
trait FlyingAbility extends Named { String fly() { "I'm a flying ${name}!" } } !
class Bird implements FlyingAbility {} def b = new Bird(name: 'Colibri') !
assert b.name == 'Colibri' assert b.fly() == "I'm a flying Colibri!"
access the name property
Traits: inheritance
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trait Named { String name } !
trait FlyingAbility extends Named { String fly() { "I'm a flying ${name}!" } } !
class Bird implements FlyingAbility {} def b = new Bird(name: 'Colibri') !
assert b.name == 'Colibri' assert b.fly() == "I'm a flying Colibri!"
implement the composite trait
Traits: inheritance
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trait Named { String name } !
trait FlyingAbility extends Named { String fly() { "I'm a flying ${name}!" } } !
class Bird implements FlyingAbility {} def b = new Bird(name: 'Colibri') !
assert b.name == 'Colibri' assert b.fly() == "I'm a flying Colibri!"
Traits: multiple inheritance & dynamic access
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trait FlyingAbility { String fly() { "I'm a flying $name!" } } !
trait Named { String name } !
class Bird implements Named, FlyingAbility {} def b = new Bird(name: 'Colibri') !
assert b.name == 'Colibri' assert b.fly() == "I'm a flying Colibri!"
Traits: multiple inheritance & dynamic access
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trait FlyingAbility { String fly() { "I'm a flying $name!" } } !
trait Named { String name } !
class Bird implements Named, FlyingAbility {} def b = new Bird(name: 'Colibri') !
assert b.name == 'Colibri' assert b.fly() == "I'm a flying Colibri!"
access a dynamic property
Traits: multiple inheritance & dynamic access
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trait FlyingAbility { String fly() { "I'm a flying $name!" } } !
trait Named { String name } !
class Bird implements Named, FlyingAbility {} def b = new Bird(name: 'Colibri') !
assert b.name == 'Colibri' assert b.fly() == "I'm a flying Colibri!"
implements two traits!
Traits: multiple inheritance & dynamic access
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trait FlyingAbility { String fly() { "I'm a flying $name!" } } !
trait Named { String name } !
class Bird implements Named, FlyingAbility {} def b = new Bird(name: 'Colibri') !
assert b.name == 'Colibri' assert b.fly() == "I'm a flying Colibri!"
dynamic ‘name’ property interpolated
Traits: multiple inheritance & dynamic access
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trait FlyingAbility { String fly() { "I'm a flying $name!" } } !
trait Named { String name } !
class Bird implements Named, FlyingAbility {} def b = new Bird(name: 'Colibri') !
assert b.name == 'Colibri' assert b.fly() == "I'm a flying Colibri!"
Traits: what about conflicts?
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trait KiteSurfer { String surf() { 'kite' } } !trait WebSurfer { String surf() { 'web' } } !class Person { String name } !class Hipster extends Person implements KiteSurfer, WebSurfer {} !def h = new Hipster() assert h.surf() == 'web'
Traits: what about conflicts?
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trait KiteSurfer { String surf() { 'kite' } } !trait WebSurfer { String surf() { 'web' } } !class Person { String name } !class Hipster extends Person implements KiteSurfer, WebSurfer {} !def h = new Hipster() assert h.surf() == 'web'
two surf() methods
Traits: what about conflicts?
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trait KiteSurfer { String surf() { 'kite' } } !trait WebSurfer { String surf() { 'web' } } !class Person { String name } !class Hipster extends Person implements KiteSurfer, WebSurfer {} !def h = new Hipster() assert h.surf() == 'web'
Traits: what about conflicts?
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trait KiteSurfer { String surf() { 'kite' } } !trait WebSurfer { String surf() { 'web' } } !class Person { String name } !class Hipster extends Person implements KiteSurfer, WebSurfer {} !def h = new Hipster() assert h.surf() == 'web'
extending a class and implementing the two traits
Traits: what about conflicts?
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trait KiteSurfer { String surf() { 'kite' } } !trait WebSurfer { String surf() { 'web' } } !class Person { String name } !class Hipster extends Person implements KiteSurfer, WebSurfer {} !def h = new Hipster() assert h.surf() == 'web'
Traits: what about conflicts?
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trait KiteSurfer { String surf() { 'kite' } } !trait WebSurfer { String surf() { 'web' } } !class Person { String name } !class Hipster extends Person implements KiteSurfer, WebSurfer {} !def h = new Hipster() assert h.surf() == 'web'
last declared trait wins!
Traits: what about conflicts?
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trait KiteSurfer { String surf() { 'kite' } } !trait WebSurfer { String surf() { 'web' } } !class Person { String name } !class Hipster extends Person implements KiteSurfer, WebSurfer {} !def h = new Hipster() assert h.surf() == 'web'
Traits: what about conflicts?
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trait KiteSurfer { String surf() { 'kite' } } !trait WebSurfer { String surf() { 'web' } } !class Person { String name } !class Hipster extends Person implements WebSurfer, KiteSurfer {} !def h = new Hipster() assert h.surf() == 'kite'
Traits: what about conflicts?
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trait KiteSurfer { String surf() { 'kite' } } !trait WebSurfer { String surf() { 'web' } } !class Person { String name } !class Hipster extends Person implements WebSurfer, KiteSurfer {} !def h = new Hipster() assert h.surf() == 'kite'
reverse the order!
Traits: what about conflicts?
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trait KiteSurfer { String surf() { 'kite' } } !trait WebSurfer { String surf() { 'web' } } !class Person { String name } !class Hipster extends Person implements WebSurfer, KiteSurfer {} !def h = new Hipster() assert h.surf() == 'kite'
Traits: what about conflicts?
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trait KiteSurfer { String surf() { 'kite' } } !trait WebSurfer { String surf() { 'web' } } !class Person { String name } !class Hipster extends Person implements WebSurfer, KiteSurfer { String surf() { KiteSurfer.super.surf() } } !def h = new Hipster() assert h.surf() == 'kite'
Traits: what about conflicts?
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trait KiteSurfer { String surf() { 'kite' } } !trait WebSurfer { String surf() { 'web' } } !class Person { String name } !class Hipster extends Person implements WebSurfer, KiteSurfer { String surf() { KiteSurfer.super.surf() } } !def h = new Hipster() assert h.surf() == 'kite'
Be explicit! Override surf()
& use ‘super’
Traits: what about conflicts?
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trait KiteSurfer { String surf() { 'kite' } } !trait WebSurfer { String surf() { 'web' } } !class Person { String name } !class Hipster extends Person implements WebSurfer, KiteSurfer { String surf() { KiteSurfer.super.surf() } } !def h = new Hipster() assert h.surf() == 'kite'
Your class method takes precedence over the traits
Traits: what about conflicts?
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trait KiteSurfer { String surf() { 'kite' } } !trait WebSurfer { String surf() { 'web' } } !class Person { String name } !class Hipster extends Person implements WebSurfer, KiteSurfer { String surf() { KiteSurfer.super.surf() } } !def h = new Hipster() assert h.surf() == 'kite'
trait Named { String name } !
class Animal {} class NamedAnimal implements Named {} !
def na = new NamedAnimal(name: 'Felix') !
assert na.name == 'Felix'
Traits: runtime implementation
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trait Named { String name } !
class Animal {} class NamedAnimal implements Named {} !
def na = new NamedAnimal(name: 'Felix') !
assert na.name == 'Felix'
Traits: runtime implementation
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Somewhat artificial to have to create an intermediary class to
get named animals
trait Named { String name } !
class Animal {} class NamedAnimal implements Named {} !
def na = new NamedAnimal(name: 'Felix') !
assert na.name == 'Felix'
Traits: runtime implementation
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trait Named { String name } !
class Animal {} !
!
def na = new Animal() as Named na.name = 'Felix' assert na.name == 'Felix'
Traits: runtime implementation
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trait Named { String name } !
class Animal {} !
!
def na = new Animal() as Named na.name = 'Felix' assert na.name == 'Felix'
Traits: runtime implementation
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Runtime trait, with Groovy’s usual
coercion mechanism
trait Named { String name } !
class Animal {} !
!
def na = new Animal() as Named na.name = 'Felix' assert na.name == 'Felix'
Traits: runtime implementation
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Traits: runtime implementation
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trait Named { String name } !
trait Quacks { String quack() { 'Quack!' } } !
class Animal {} !
def na = new Animal().withTraits Named, Quacks na.name = 'Daffy' assert na.name == 'Daffy' assert na.quack() == 'Quack!'
Traits: runtime implementation
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trait Named { String name } !
trait Quacks { String quack() { 'Quack!' } } !
class Animal {} !
def na = new Animal().withTraits Named, Quacks na.name = 'Daffy' assert na.name == 'Daffy' assert na.quack() == 'Quack!'
Implement several traits at once, at runtime
Traits: runtime implementation
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trait Named { String name } !
trait Quacks { String quack() { 'Quack!' } } !
class Animal {} !
def na = new Animal().withTraits Named, Quacks na.name = 'Daffy' assert na.name == 'Daffy' assert na.quack() == 'Quack!'
Traits: miscellaneous
• Traits can… !
• have private fields and methods • have abstract methods • implement interfaces • extend other traits or implement several traits • be statically type checked and compiled
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To know all about traits!
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Rethinking API design with traits by Cédric Champeau Tue 2:30pm / Trinity 3
© 2014 SpringOne 2GX. All rights reserved. Do not distribute without permission.
AST transforms
New: @TailRecursive
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import groovy.transform.TailRecursive !
@TailRecursive def fact(BigInteger n, accu = 1G) { if (n < 2) accu else fact(n -‐ 1, n * accu) } !
assert fact(1000) > 10e2566
New: @TailRecursive
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import groovy.transform.TailRecursive !
@TailRecursive def fact(BigInteger n, accu = 1G) { if (n < 2) accu else fact(n -‐ 1, n * accu) } !
assert fact(1000) > 10e2566
Rewrites tail recursive friendly function serially
New: @TailRecursive
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import groovy.transform.TailRecursive !
@TailRecursive def fact(BigInteger n, accu = 1G) { if (n < 2) accu else fact(n -‐ 1, n * accu) } !
assert fact(1000) > 10e2566
Doesn’t blow up with a stack overflow error
New: @TailRecursive
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import groovy.transform.TailRecursive !
@TailRecursive def fact(BigInteger n, accu = 1G) { if (n < 2) accu else fact(n -‐ 1, n * accu) } !
assert fact(1000) > 10e2566
Downside of tail recursion is you might have to rewrite
your algo to be tailrec friendly
New: @TailRecursive
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import groovy.transform.TailRecursive !
@TailRecursive def fact(BigInteger n, accu = 1G) { if (n < 2) accu else fact(n -‐ 1, n * accu) } !
assert fact(1000) > 10e2566
New: @Sortable
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import groovy.transform.* !
@Sortable class Person { String lastName String firstName int age }
New: @Sortable
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import groovy.transform.* !
@Sortable class Person { String lastName String firstName int age }
Makes the class Comparable by multiple Comparators
New: @Sortable
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import groovy.transform.* !
@Sortable class Person { String lastName String firstName int age }
First compare by lastName, then by firstName, etc.
New: @Sortable
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import groovy.transform.* !
@Sortable class Person { String lastName String firstName int age }
You can also specify ‘includes’ / ‘excludes’
properties
New: @Sortable
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import groovy.transform.* !
@Sortable class Person { String lastName String firstName int age }
@BaseScript improvements
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abstract class CustomBase extends Script { int meaningOfLife = 42 }
@BaseScript(CustomBase) import groovy.transform.BaseScript !
assert meaningOfLife == 42
@BaseScript improvements
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abstract class CustomBase extends Script { int meaningOfLife = 42 }
@BaseScript(CustomBase) import groovy.transform.BaseScript !
assert meaningOfLife == 42
You can add your own base methods and properties to all compiled scripts
@BaseScript improvements
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abstract class CustomBase extends Script { int meaningOfLife = 42 }
@BaseScript(CustomBase) import groovy.transform.BaseScript !
assert meaningOfLife == 42
Define the base script class for this script
@BaseScript improvements
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abstract class CustomBase extends Script { int meaningOfLife = 42 }
@BaseScript(CustomBase) import groovy.transform.BaseScript !
assert meaningOfLife == 42
Ability to put the annotation on imports & package
@BaseScript improvements
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abstract class CustomBase extends Script { int meaningOfLife = 42 }
@BaseScript(CustomBase) import groovy.transform.BaseScript !
assert meaningOfLife == 42
@BaseScript custom abstract method
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abstract class CustomBase extends Script { def run() { before() internalRun() after() } ! abstract internalRun() ! def before() { println 'before' } def after() { println 'after' } }
@BaseScript custom abstract method
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abstract class CustomBase extends Script { def run() { before() internalRun() after() } ! abstract internalRun() ! def before() { println 'before' } def after() { println 'after' } }
import groovy.transform.BaseScript @BaseScript CustomBase script !println 'Hello'
@BaseScript custom abstract method
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abstract class CustomBase extends Script { def run() { before() internalRun() after() } ! abstract internalRun() ! def before() { println 'before' } def after() { println 'after' } }
import groovy.transform.BaseScript @BaseScript CustomBase script !println 'Hello'
You can define your own abstract method for script bodies
@BaseScript custom abstract method
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abstract class CustomBase extends Script { def run() { before() internalRun() after() } ! abstract internalRun() ! def before() { println 'before' } def after() { println 'after' } }
import groovy.transform.BaseScript @BaseScript CustomBase script !println 'Hello'
To know all about AST transformations!
33
Groovy AST transformations by Paul King Wed 2:30pm / Trinity 3
To know all about AST transformations!
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Writing AST transformations by Simon / Sadogursky Thu 10:30pm / F. Park 3
© 2014 SpringOne 2GX. All rights reserved. Do not distribute without permission.
NIO2 module
JDK 7+ NIO2 module
• All the familiar methods on File retrofitted on Path as well
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path.withReader { Reader r -‐> ... } path.eachLine { String line -‐> ... } path.eachFileRecurse { Path p -‐> ... } path << 'some content' path << bytes path.readLines() …
JDK 7+ NIO2 module
• All the familiar methods on File retrofitted on Path as well
36
path.withReader { Reader r -‐> ... } path.eachLine { String line -‐> ... } path.eachFileRecurse { Path p -‐> ... } path << 'some content' path << bytes path.readLines() …
Feature request to add all the java.nio.file.Files static utility
methods as GDK
JDK 7+ NIO2 module
• All the familiar methods on File retrofitted on Path as well
36
path.withReader { Reader r -‐> ... } path.eachLine { String line -‐> ... } path.eachFileRecurse { Path p -‐> ... } path << 'some content' path << bytes path.readLines() …
© 2014 SpringOne 2GX. All rights reserved. Do not distribute without permission.
JSON
JSON parser / builder perf. increase
• Re-implementation of JSON support for speed & efficiency • parser forked off the Boon JSON project • serializer carefully fine-tuned !
• Article on the parsing speed improvements • http://rick-hightower.blogspot.fr/2014/04/groovy-and-boon-provide-fastest-json.html
38
JSON parser / builder perf. increase
• Re-implementation of JSON support for speed & efficiency • parser forked off the Boon JSON project • serializer carefully fine-tuned !
• Article on the parsing speed improvements • http://rick-hightower.blogspot.fr/2014/04/groovy-and-boon-provide-fastest-json.html
38
JSON parser / builder perf. increase
• Re-implementation of JSON support for speed & efficiency • parser forked off the Boon JSON project • serializer carefully fine-tuned !
• Article on the parsing speed improvements • http://rick-hightower.blogspot.fr/2014/04/groovy-and-boon-provide-fastest-json.html
38
Benchmark gives 3x to 4x performance factor
over Jackson and GSON
JSON parser / builder perf. increase
• Re-implementation of JSON support for speed & efficiency • parser forked off the Boon JSON project • serializer carefully fine-tuned !
• Article on the parsing speed improvements • http://rick-hightower.blogspot.fr/2014/04/groovy-and-boon-provide-fastest-json.html
38
New modes for parsing
• Original JsonSlurper renamed to JsonSlurperClassic !
• Additional parsing modes: • INDEX_OVERLAY: super fast for <2MB payloads
o using a « parsing overlay » technique • CHARACTER_SOURCE: for >2MB payloads
o implemented with sliding windows over readers • LAX: beyond the JSON spec, nice for configuration files
o support single quotes, / and # comments • CHAR_BUFFER: general purpose
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JsonSlurper for configuration files
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import groovy.json.* import static groovy.json.JsonParserType.* !def parser = new JsonSlurper().setType(LAX) !def conf = parser.parseText ''' // configuration file { // no quote for key, single quoted value environment: 'production' # pound-‐style comment 'server': 5 } ''' !assert conf.environment == 'production' assert conf.server == 5
JsonSlurper for configuration files
40
import groovy.json.* import static groovy.json.JsonParserType.* !def parser = new JsonSlurper().setType(LAX) !def conf = parser.parseText ''' // configuration file { // no quote for key, single quoted value environment: 'production' # pound-‐style comment 'server': 5 } ''' !assert conf.environment == 'production' assert conf.server == 5
More tolerant parser: single quotes,
non-quoted keys, // and # comments,
missing comas
JsonSlurper for configuration files
40
import groovy.json.* import static groovy.json.JsonParserType.* !def parser = new JsonSlurper().setType(LAX) !def conf = parser.parseText ''' // configuration file { // no quote for key, single quoted value environment: 'production' # pound-‐style comment 'server': 5 } ''' !assert conf.environment == 'production' assert conf.server == 5
© 2014 SpringOne 2GX. All rights reserved. Do not distribute without permission.
Markup template engine
</>
Markup template engine
• Based on the principles of Groovy’s « builders » • and particularly the MarkupBuilder class
for generating arbitrary XML / HTML payloads !
• Compiled statically for fast template rendering !
• Internationalization aware • provide the desired Locale in the configuration object • usual suffix notation template_fr_FR.tpl !
• Custom base template class • ability to provide reusable methods across your templates 42
Markup template engine
• Based on the principles of Groovy’s « builders » • and particularly the MarkupBuilder class
for generating arbitrary XML / HTML payloads !
• Compiled statically for fast template rendering !
• Internationalization aware • provide the desired Locale in the configuration object • usual suffix notation template_fr_FR.tpl !
• Custom base template class • ability to provide reusable methods across your templates 42
Spring Boot approved
Markup template engine — the idea
43
cars { cars.each { car(make: it.make, name: it.name) } }
Markup template engine — the idea
43
cars { cars.each { car(make: it.make, name: it.name) } }
Your template
Markup template engine — the idea
43
cars { cars.each { car(make: it.make, name: it.name) } }
model = [cars: [! new Car(make: 'Peugeot', name: '508'), ! new Car(make: 'Toyota', name: 'Prius’)!]]
Markup template engine — the idea
43
cars { cars.each { car(make: it.make, name: it.name) } }
model = [cars: [! new Car(make: 'Peugeot', name: '508'), ! new Car(make: 'Toyota', name: 'Prius’)!]]
Feed a model into your template
Markup template engine — the idea
43
cars { cars.each { car(make: it.make, name: it.name) } }
model = [cars: [! new Car(make: 'Peugeot', name: '508'), ! new Car(make: 'Toyota', name: 'Prius’)!]]
<cars>! <car make='Peugeot' name='508'/>! <car make='Toyota' name='Prius'/>!</cars>
Markup template engine — the idea
43
cars { cars.each { car(make: it.make, name: it.name) } }
model = [cars: [! new Car(make: 'Peugeot', name: '508'), ! new Car(make: 'Toyota', name: 'Prius’)!]]
<cars>! <car make='Peugeot' name='508'/>! <car make='Toyota' name='Prius'/>!</cars>
Generate the XML output
Markup template engine — the idea
43
cars { cars.each { car(make: it.make, name: it.name) } }
model = [cars: [! new Car(make: 'Peugeot', name: '508'), ! new Car(make: 'Toyota', name: 'Prius’)!]]
<cars>! <car make='Peugeot' name='508'/>! <car make='Toyota' name='Prius'/>!</cars>
Markup template engine — in action
44
import groovy.text.markup.* !def config = new TemplateConfiguration() def engine = new MarkupTemplateEngine(config) def tmpl = engine.createTemplate(''' p("Hello ${model.name}") ''') def model = [name: 'World'] System.out << tmpl.make(model)
Markup template engine — includes
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// include another template include template: 'foo.tpl' // include raw content include unescaped: 'raw.txt' !
// escape & include include escaped: 'to_escape.txt'
Markup template engine
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// escaped automatically yield 'some raw content' !// include raw content yieldUnescaped 'content' !// <?xml version='1.0'?> xmlDeclaration()
Markup template engine
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// escaped automatically yield 'some raw content' !// include raw content yieldUnescaped 'content' !// <?xml version='1.0'?> xmlDeclaration()
// <!-‐-‐comment-‐-‐> comment 'comment' !// adds new lines newLine() !// process. instruct. pi(/* ... */)
Markup template engine — configuration options
!!!
• declaration encoding !
• expand empty elements !
• use double quotes !
• newline string !!!!!!!
!!
!• auto escape
!• auto indent
!• base template class
!• locale
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Markup template engine — static!
• Type-checked templates available • use createTypeCheckedModelTemplate()
instead of createTemplate() !
• Advantages • get compilation errors
o if a variable is not available o if you make mistakes in the code snippets
• even faster templates
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Markup template engine — static!
• With typed check model creation method
!
!
!
!
!
!
!
!
!
• Or declare your model types in the template
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Markup template engine — static!
• With typed check model creation method
!
!
!
!
!
!
!
!
!
• Or declare your model types in the template
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def modelTypes = [cars: "List<Car>"] !def tmpl = engine. createTypeCheckedModelTemplate( "page.tpl", modelTypes)
Markup template engine — static!
• With typed check model creation method
!
!
!
!
!
!
!
!
!
• Or declare your model types in the template
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def modelTypes = [cars: "List<Car>"] !def tmpl = engine. createTypeCheckedModelTemplate( "page.tpl", modelTypes)
modelTypes = { List<Car> cars } !cars.each { car -‐> p("Car name: $car.name") }
Markup template engine — static!
• With typed check model creation method
!
!
!
!
!
!
!
!
!
• Or declare your model types in the template
49
def modelTypes = [cars: "List<Car>"] !def tmpl = engine. createTypeCheckedModelTemplate( "page.tpl", modelTypes)
modelTypes = { List<Car> cars } !cars.each { car -‐> p("Car name: $car.name") }
Works with createTemplate() too
Markup template engine — static!
• With typed check model creation method
!
!
!
!
!
!
!
!
!
• Or declare your model types in the template
49
def modelTypes = [cars: "List<Car>"] !def tmpl = engine. createTypeCheckedModelTemplate( "page.tpl", modelTypes)
modelTypes = { List<Car> cars } !cars.each { car -‐> p("Car name: $car.name") }
© 2014 SpringOne 2GX. All rights reserved. Do not distribute without permission.
Documentation overhaul
GroovyDoc
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GroovyDoc
51
GroovyDoc
51
Groovy GDK documentation
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Groovy GDK documentation
52
Brand new documentation
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© 2014 SpringOne 2GX. All rights reserved. Do not distribute without permission.
Groovy 2.4
Android support
• You can use Groovy to code Android apps! • use Groovy 2.4.0-beta-1+ • prefer @CompileStatic !
• Two great posts to get started: • http://melix.github.io/blog/2014/06/grooid.html • http://melix.github.io/blog/2014/06/grooid2.html
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New York Times — Getting Groovy with Android
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Android support
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Android support
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Android support
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Source code available:https://github.com/melix/gr8confagenda
To know all about AST transformations!
59
Groovy & Android, a winning pair? by Cédric Champeau Thu 12:45pm / Trinity 3
Groovy Macros
!
• Sergei Egorov wants to contribute a macro module • https://github.com/groovy/groovy-core/pull/470 !
• Simplify creation of AST transformations • less boilerplate manipulating the Groovy AST API • more powerful and less limited than AstBuilder
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Groovy Macros
!
• Authoring AST transformations can be verbose:
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def someVariable = new ConstantExpression("xyz") def returnStatement = new ReturnStatement( new ConstructorCallExpression( ClassHelper.make(SomeCoolClass), new ArgumentListExpression(someVariable) ) )
Groovy Macros
• With Groovy Macros, it could be simpler:
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def someVariable = macro { "xyz" } def returnStatement = macro { new SomeCoolClass($v{ someVariable }) }
Groovy Macros
• With Groovy Macros, it could be simpler:
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def someVariable = macro { "xyz" } def returnStatement = macro { new SomeCoolClass($v{ someVariable }) }
Special « macro » command
Groovy Macros
• With Groovy Macros, it could be simpler:
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def someVariable = macro { "xyz" } def returnStatement = macro { new SomeCoolClass($v{ someVariable }) }
Special « macro » command
Quasi-quotation
© 2014 SpringOne 2GX. All rights reserved. Do not distribute without permission.
Groovy 3.0
© 2014 SpringOne 2GX. All rights reserved. Do not distribute without permission.
New Age Meta-Object Protocol
MOP 2
Goals for the new MOP
• Leverage & build upon JDK 7+ invoke dynamic • get Java-like performance even for dynamic code
• Rationalize the sedimentation of meta-programming • more coherence, less corner cases & inconsistencies
• Provide a notion of « realm » • shield users of « monkey patching » • finer-grained control of meta-programming reach
• Private visibility anyone?
66
© 2014 SpringOne 2GX. All rights reserved. Do not distribute without permission.
Rewriting the Groovy grammar
with Antlr v4
Antlr v4 Grammar
Antlr v4 grammar
• Problems • Groovy still uses Antlr v2!
o but version 3 and 4 are out • Groovy’s grammar evolved from a Java grammar
o harder to fix and evolve, especially with Antlr v2 • Advantages
• Start from a clean slate • Antlr 4 more tolerant
and powerful regarding ambiguities • Time to clean some grammar & syntax warts! • Need to implement the Java 8 constructs!
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Antlr v4 grammar
• Problems • Groovy still uses Antlr v2!
o but version 3 and 4 are out • Groovy’s grammar evolved from a Java grammar
o harder to fix and evolve, especially with Antlr v2 • Advantages
• Start from a clean slate • Antlr 4 more tolerant
and powerful regarding ambiguities • Time to clean some grammar & syntax warts! • Need to implement the Java 8 constructs!
68
A « Google Summer of Code » student is currently helping
© 2014 SpringOne 2GX. All rights reserved. Do not distribute without permission.
Support the new Java 8
language features
Java 8 language support
Java 8 support
• Additional grammar & semantic features to support • to keep saying Groovy / Java interoperability is awesome!
• New in Java 8 • lambdas • method references • default methods in interfaces • stream API, date / time API • annotations on types & repeated annotations
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Java 8 support
• Additional grammar & semantic features to support • to keep saying Groovy / Java interoperability is awesome!
• New in Java 8 • lambdas • method references • default methods in interfaces • stream API, date / time API • annotations on types & repeated annotations
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Groovy had already: closures, method pointers, mixins,
enriched collection & time APIs
To know all about AST transformations!
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How to get Groovy with Java 8 by Peter Ledbrook Thu 10:30pm / Trinity 3
© 2014 SpringOne 2GX. All rights reserved. Do not distribute without permission.
Summary
Groovy rocks the JVM since 2003!
© 2014 SpringOne 2GX. All rights reserved. Do not distribute without permission.
Q & A
Image credits• Big rock
• http://wallpaper.preview-reviews.com/12852-red-rocks-in-a-snowstorm • Android robot
• http://crackberry.com/sites/crackberry.com/files/styles/large/public/topic_images/2013/ANDROID.png?itok=xhm7jaxS • Modern MOP
• http://i933.photobucket.com/albums/ad179/autobin/Wonder%20Mop/wondermop4.jpg • Jason
• http://static.comicvine.com/uploads/original/3/32405/1031312-jason_19_inch_figure_l.jpg • Jigsaw
• http://www.psdgraphics.com/file/psd-jigsaw-icon.jpg • Many thanks
• http://www.trys.ie/wp-content/uploads/2013/06/many-thanks.jpg
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