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Groovy, in the light of Java 8Guillaume Laforge — Groovy project lead / Pivotal

@glaforge

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Groovy Weekly Newsletter (Every Tuesday) http://beta.groovy-lang.org/groovy-weekly.html

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Google+ Groovy Community http://bit.ly/g-community

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Goal of this talk

A recurring question…

Do we still need Groovy now that we

have Java 8?

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To those who said no…

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But more precisely…

• Will Java lambdas replace Groovy closures? • What are the differences between them? !

• Will Groovy support all the new Java 8 language constructs? • lambdas, default methods, method references… !

• How Groovy developers can benefit from Java 8? !

• What does Groovy offer beyond Java 8?

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What about redundancy?

!

!

!

!

!

• Closures • Traits • Truth & null handling • Functional with collections • Method closures

!

!

!

!

!

!

!

• Lambdas • Default methods • Optional • Stream API • Method references

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© 2014 SpringOne 2GX. All rights reserved. Do not distribute without permission.

Agenda

What we’re going to talk about

• What’s new in Java 8 • new syntax constructs • new APIs !

• Similar concepts in Groovy • and how they compare or complement !

• What Groovy offers in addition • beyond Java, Groovy adds its own twist!

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© 2014 SpringOne 2GX. All rights reserved. Do not distribute without permission.

What’s new in Java 8?

This is not a Java 8 crash courses with all the details :-)

This is not a Java 8 crash courses with all the details :-)

We want to understand the implications with regards to Groovy

What’s new in Java 8?

!

• New syntax • Streams • Profiles • Security enhancements • JavaFX • Tools • i18n • Date / time API • Nashorn / JavaScript

!

!

!

• Pack200 • IO / NIO improvements • New utility classes • JDBC • Networking • Concurrency • JAXP • Hotspot • Java Mission Control

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What’s new in Java 8?

!

• New syntax • Streams • Profiles • Security enhancements • JavaFX • Tools • i18n • Date / time API • Nashorn / JavaScript

!

!

!

• Pack200 • IO / NIO improvements • New utility classes • JDBC • Networking • Concurrency • JAXP • Hotspot • Java Mission Control

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Great concise resource with the whole list:http://bit.ly/new-in-java-8

© 2014 SpringOne 2GX. All rights reserved. Do not distribute without permission.

Support the new Java 8

language features

New Java 8 syntax

New Java 8 syntax constructs

• Lambda expressions • Method references • Static & default methods in interfaces • Repeating annotations • Annotations on types • Improved type inference • Method parameter reflection

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New Java 8 syntax constructs

• Lambda expressions • Method references • Static & default methods in interfaces • Repeating annotations • Annotations on types • Improved type inference • Method parameter reflection

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Lambda expressions

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double highestScore = students .filter(Student s -> s.getGradYear() == 2011) .map(Student s -> s.getScore()) .max();

Lambda expressions

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double highestScore = students .filter(Student s -> s.getGradYear() == 2011) .map(Student s -> s.getScore()) .max();

Lambda expressions

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double highestScore = students .filter(Student s -> s.getGradYear() == 2011) .map(Student s -> s.getScore()) .max();

Coercion into a Predicate « functional interface »

Lambda expressions

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double highestScore = students .filter(Student s -> s.getGradYear() == 2011) .map(Student s -> s.getScore()) .max();

There’s no function type!

Lambda expressions

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double highestScore = students .filter(Student s -> s.getGradYear() == 2011) .map(Student s -> s.getScore()) .max();

Pipeline being built Single pass!

Lambda expressions

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double highestScore = students .filter(Student s -> s.getGradYear() == 2011) .map(Student s -> s.getScore()) .max();

Lambda expressions

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double highestScore = students .findAll { it.gradYear == 2011 } .collect { it.score} .max()

Lambda expressions

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double highestScore = students .findAll { it.gradYear == 2011 } .collect { it.score} .max()

In Groovy, that would be…

Lambda expressions

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double highestScore = students .findAll { it.gradYear == 2011 } .collect { it.score} .max()

Drawback: intermediary data structures Unless you use iterator variants

Lambda expressions

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double highestScore = students .findAll { it.gradYear == 2011 } .collect { it.score} .max()

The various lambda syntaxes

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String name -> name.length() !

(int left, int right) -> left + right !

(String left, String sep, String right) -> { System.out.println(left + sep + right) }

The various lambda syntaxes

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String name -> name.length() !

(int left, int right) -> left + right !

(String left, String sep, String right) -> { System.out.println(left + sep + right) }

One parameter: no parens Expression on right: no curly

The various lambda syntaxes

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String name -> name.length() !

(int left, int right) -> left + right !

(String left, String sep, String right) -> { System.out.println(left + sep + right) }

Parentheses required for more that one parameter

The various lambda syntaxes

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String name -> name.length() !

(int left, int right) -> left + right !

(String left, String sep, String right) -> { System.out.println(left + sep + right) }

Statements require curly braces Return keyword required if non-void returning

The various lambda syntaxes

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String name -> name.length() !

(int left, int right) -> left + right !

(String left, String sep, String right) -> { System.out.println(left + sep + right) }

The various lambda syntaxes

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name -> name.length() !

(left, right) -> left + right !

(left, sep, right) -> { System.out.println(left + sep + right) }

The various lambda syntaxes

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name -> name.length() !

(left, right) -> left + right !

(left, sep, right) -> { System.out.println(left + sep + right) }

Clever type inference can help get rid of parameter

type declarations

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));

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 }

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 closures wherever you pass lambdas in Java 8

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 }

Groovy coerces to SAM types (Single Abstract Method)

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 }

Beyond: Closure default parameters

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def mult = { int a, int b = 10 -> a * b } !

assert mult(2, 3) == 6 assert mult(5) == 50

Beyond: Closure default parameters

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def mult = { int a, int b = 10 -> a * b } !

assert mult(2, 3) == 6 assert mult(5) == 50

Default value if the parameter is not specified

Beyond: Duck typing polymorphism

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def adder = { a, b -> a + b } !

assert adder(100, 200) == 300 assert adder('X', 'Y') == 'XY'

Beyond: Duck typing polymorphism

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def adder = { a, b -> a + b } !

assert adder(100, 200) == 300 assert adder('X', 'Y') == 'XY'

Works both for numbers and for strings

Builders

BuildersWhat would Java lambda

builders look like?

BuildersWhat would Java lambda

builders look like?

Aren’t Groovy builders more powerful?

Lambda-based builders uglier and less powerful

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MarkupBuilder pom = new XmlMarkupBuilder() pom.el("modelVersion", "4.0.0"); pom.el("groupId", "com.github"); pom.el("artifactId", "lambda-builder"); pom.el("version", "1.0-SNAPSHOT"); pom.el("dependencies", () -> { pom.el("dependency", () -> { pom.el("groupId", "junit"); pom.el("artifactId", "junit"); pom.elx("version", "4.11"); }); pom.el("dependency", () -> { pom.el("groupId", "commons-beanutils"); pom.el("artifactId", "commons-beanutils"); pom.elx("version", "1.7.0"); }); });

Lambda-based builders uglier and less powerful

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MarkupBuilder pom = new XmlMarkupBuilder() pom.el("modelVersion", "4.0.0"); pom.el("groupId", "com.github"); pom.el("artifactId", "lambda-builder"); pom.el("version", "1.0-SNAPSHOT"); pom.el("dependencies", () -> { pom.el("dependency", () -> { pom.el("groupId", "junit"); pom.el("artifactId", "junit"); pom.elx("version", "4.11"); }); pom.el("dependency", () -> { pom.el("groupId", "commons-beanutils"); pom.el("artifactId", "commons-beanutils"); pom.elx("version", "1.7.0"); }); });

Repeated « pom »: No delegate like in Groovy’s closures

Lambda-based builders uglier and less powerful

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MarkupBuilder pom = new XmlMarkupBuilder() pom.el("modelVersion", "4.0.0"); pom.el("groupId", "com.github"); pom.el("artifactId", "lambda-builder"); pom.el("version", "1.0-SNAPSHOT"); pom.el("dependencies", () -> { pom.el("dependency", () -> { pom.el("groupId", "junit"); pom.el("artifactId", "junit"); pom.elx("version", "4.11"); }); pom.el("dependency", () -> { pom.el("groupId", "commons-beanutils"); pom.el("artifactId", "commons-beanutils"); pom.elx("version", "1.7.0"); }); });

Zero-arg lamdas not as lean

Lambda-based builders uglier and less powerful

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MarkupBuilder pom = new XmlMarkupBuilder() pom.el("modelVersion", "4.0.0"); pom.el("groupId", "com.github"); pom.el("artifactId", "lambda-builder"); pom.el("version", "1.0-SNAPSHOT"); pom.el("dependencies", () -> { pom.el("dependency", () -> { pom.el("groupId", "junit"); pom.el("artifactId", "junit"); pom.elx("version", "4.11"); }); pom.el("dependency", () -> { pom.el("groupId", "commons-beanutils"); pom.el("artifactId", "commons-beanutils"); pom.elx("version", "1.7.0"); }); });

Generic method + string: No dynamic

method

Neater Groovy builder!

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def pom = new PomBuilder().project { modelVersion "4.0.0" groupId "com.github" artifactId "lambda-builder" version "1.0-SNAPSHOT" dependencies { dependency { groupId "junit" artifactId "junit" version "4.11" } dependency { groupId "commons-beanutils" artifactId "commons-beanutils" version "1.7.0" } } }

Neater Groovy builder!

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def pom = new PomBuilder().project { modelVersion "4.0.0" groupId "com.github" artifactId "lambda-builder" version "1.0-SNAPSHOT" dependencies { dependency { groupId "junit" artifactId "junit" version "4.11" } dependency { groupId "commons-beanutils" artifactId "commons-beanutils" version "1.7.0" } } }

Aren’t Groovy builders more readable and lean?

To those who said no…

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Memoization

Closure and method memoization

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def fib2 = { long n -> if (n < 2) 1 else call(n - 1) + call(n - 2) }.memoize()

Closure and method memoization

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def fib2 = { long n -> if (n < 2) 1 else call(n - 1) + call(n - 2) }.memoize()

Closures:memoize()

Closure and method memoization

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@Memoized long fib(long n) { if (n < 2) 1 else fib(n - 1) + fib(n - 2) }

def fib2 = { long n -> if (n < 2) 1 else call(n - 1) + call(n - 2) }.memoize()

Closures:memoize()

Closure and method memoization

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@Memoized long fib(long n) { if (n < 2) 1 else fib(n - 1) + fib(n - 2) }

def fib2 = { long n -> if (n < 2) 1 else call(n - 1) + call(n - 2) }.memoize()

Closures:memoize()

Methods:memoization AST transformation

Tail recursion

Closure and method tail recursion

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def fact = { n, accu = 1G -> if (n < 2) accu else fact.trampoline(n - 1, n * accu) }.trampoline()

Closure and method tail recursion

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def fact = { n, accu = 1G -> if (n < 2) accu else fact.trampoline(n - 1, n * accu) }.trampoline()

Closures:Tail recursion with

trampoline()

Closure and method tail recursion

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@groovy.transform.TailRecursive def fact(n, accu = 1G) { if (n < 2) accu else fact(n - 1, n * accu) }

def fact = { n, accu = 1G -> if (n < 2) accu else fact.trampoline(n - 1, n * accu) }.trampoline()

Closures:Tail recursion with

trampoline()

Closure and method tail recursion

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@groovy.transform.TailRecursive def fact(n, accu = 1G) { if (n < 2) accu else fact(n - 1, n * accu) }

def fact = { n, accu = 1G -> if (n < 2) accu else fact.trampoline(n - 1, n * accu) }.trampoline()

Closures:Tail recursion with

trampoline()

Methods:Tail recursion with

@TailRecursivetransformation

Method references

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button.setOnAction(event -> System.out.println(event));

Method references

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button.setOnAction(event -> System.out.println(event));

button.setOnAction(System.out::println);

Method references — 3 main cases

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instance::instanceMethod !

SomeClass::staticMethod !

SomeClass::instanceMethod

Method references — 3 main cases

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instance::instanceMethod !

SomeClass::staticMethod !

SomeClass::instanceMethod

Not covered by Groovy method

closures yet!

Groovy’s method closure

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instance.&instanceMethod !

SomeClass.&staticMethod !

SomeClass.&instanceMethod

Groovy’s method closure

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instance.&instanceMethod !

SomeClass.&staticMethod !

SomeClass.&instanceMethod

Choices:Adopt ::

Deprecate .& Enhance .&

Static methods in interfaces

• You can put static utility methods in interfaces, instead of in companion classes (like « Collections »)

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public interface Stream<T> { // ... static <T> Stream<T> empty() { return new Stream<T> { ... } } }

Default methods in interfaces

• Define default behavior • possibly to enrich existing interfaces

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public interface Stream<T> { // ... default Builder<T> add(T t) { ... } }

Groovy 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 41

Simple trait

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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 with state

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trait Named { String name } !

class Bird implements Named {} def b = new Bird(name: 'Colibri') !

assert b.name == 'Colibri'

Multiple inheritance

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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'

To know all about traits!

45

Rethinking API design with traits by Cédric Champeau Tue 2:30pm / Trinity 3

Annotations on types

Repeating annotations

Repeating annotations

47

@Schedule(dayOfMonth = "last") @Schedule(dayOfWeek = "Fri", hour = 23) public void doPeriodicCleanup() { ... }

Repeating annotations

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@Schedule(dayOfMonth = "last") @Schedule(dayOfWeek = "Fri", hour = 23) public void doPeriodicCleanup() { ... }

@Schedule annotation repeated twice

Repeating annotations

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@Schedule(dayOfMonth = "last") @Schedule(dayOfWeek = "Fri", hour = 23) public void doPeriodicCleanup() { ... }

@Repeatable(Schedules.class) public @interface Schedule { String dayOfMonth() default "first"; String dayOfWeek() default "Mon"; int hour() default 12; }

Repeating annotations

47

@Schedule(dayOfMonth = "last") @Schedule(dayOfWeek = "Fri", hour = 23) public void doPeriodicCleanup() { ... }

@Repeatable(Schedules.class) public @interface Schedule { String dayOfMonth() default "first"; String dayOfWeek() default "Mon"; int hour() default 12; }

Container annotation for the repeated annotationd

Repeating annotations

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@Schedule(dayOfMonth = "last") @Schedule(dayOfWeek = "Fri", hour = 23) public void doPeriodicCleanup() { ... }

@Repeatable(Schedules.class) public @interface Schedule { String dayOfMonth() default "first"; String dayOfWeek() default "Mon"; int hour() default 12; }

public @interface Schedules { Schedule[] value(); }

Repeating annotations

47

@Schedule(dayOfMonth = "last") @Schedule(dayOfWeek = "Fri", hour = 23) public void doPeriodicCleanup() { ... }

@Repeatable(Schedules.class) public @interface Schedule { String dayOfMonth() default "first"; String dayOfWeek() default "Mon"; int hour() default 12; }

public @interface Schedules { Schedule[] value(); }

The container annotation iteself

Repeating annotations

47

@Schedule(dayOfMonth = "last") @Schedule(dayOfWeek = "Fri", hour = 23) public void doPeriodicCleanup() { ... }

@Repeatable(Schedules.class) public @interface Schedule { String dayOfMonth() default "first"; String dayOfWeek() default "Mon"; int hour() default 12; }

public @interface Schedules { Schedule[] value(); }

Repeating annotations

47

@Schedule(dayOfMonth = "last") @Schedule(dayOfWeek = "Fri", hour = 23) public void doPeriodicCleanup() { ... }

@Repeatable(Schedules.class) public @interface Schedule { String dayOfMonth() default "first"; String dayOfWeek() default "Mon"; int hour() default 12; }

public @interface Schedules { Schedule[] value(); }

Not yet supported

Repeating annotations

47

@Schedule(dayOfMonth = "last") @Schedule(dayOfWeek = "Fri", hour = 23) public void doPeriodicCleanup() { ... }

@Repeatable(Schedules.class) public @interface Schedule { String dayOfMonth() default "first"; String dayOfWeek() default "Mon"; int hour() default 12; }

public @interface Schedules { Schedule[] value(); }

Annotations on types

• Everywhere you can put a type, you can put an annotation

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@NonNull String name; !email = (@Email String) input; !List<@NonNull String> names; !new @Interned MyObject(); !void monitorTemperature() throws @Critical TemperatureException { ... } !class UnmodifiableList<T> implements @Readonly List<@Readonly T> {...}

Annotations on types

• Everywhere you can put a type, you can put an annotation

48

@NonNull String name; !email = (@Email String) input; !List<@NonNull String> names; !new @Interned MyObject(); !void monitorTemperature() throws @Critical TemperatureException { ... } !class UnmodifiableList<T> implements @Readonly List<@Readonly T> {...}

Not yet supported

Annotations on types

• Everywhere you can put a type, you can put an annotation

48

@NonNull String name; !email = (@Email String) input; !List<@NonNull String> names; !new @Interned MyObject(); !void monitorTemperature() throws @Critical TemperatureException { ... } !class UnmodifiableList<T> implements @Readonly List<@Readonly T> {...}

Imagine the potential for targets for local AST

transformations?

Annotations on types

• Everywhere you can put a type, you can put an annotation

48

@NonNull String name; !email = (@Email String) input; !List<@NonNull String> names; !new @Interned MyObject(); !void monitorTemperature() throws @Critical TemperatureException { ... } !class UnmodifiableList<T> implements @Readonly List<@Readonly T> {...}

Groovy compile-time meta-annotations

49

@Service @Transactional class MyTransactionalService {}

Groovy compile-time meta-annotations

49

@Service @Transactional class MyTransactionalService {}

import groovy.transform.AnnotationCollector !@Service @Transactional @AnnotationCollector public @interface TransactionalService {}

Groovy compile-time meta-annotations

49

import groovy.transform.AnnotationCollector !@Service @Transactional @AnnotationCollector public @interface TransactionalService {}

!@TransactionalService class MyTransactionalService {}

Groovy compile-time meta-annotations

49

import groovy.transform.AnnotationCollector !@Service @Transactional @AnnotationCollector public @interface TransactionalService {}

!@TransactionalService class MyTransactionalService {}

Can handle parameters (even conflicting), or you can create

your own « processor »

Groovy compile-time meta-annotations

49

import groovy.transform.AnnotationCollector !@Service @Transactional @AnnotationCollector public @interface TransactionalService {}

!@TransactionalService class MyTransactionalService {}

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New Java 8 APIs

Date and

Time API

Date / Time API

52

LocalDate.now(); today.with(TemporalAdjusters.lastDayOfMonth()).minusDays(2); !LocalDate.of(2012, Month.MAY, 14); dateOfBirth.plusYears(1); !LocalDate date = LocalDate.of(2000, Month.NOVEMBER, 20); LocalDate nextWed = date.with(TemporalAdjusters.next(DayOfWeek.WEDNESDAY));

Date / Time API

52

LocalDate.now(); today.with(TemporalAdjusters.lastDayOfMonth()).minusDays(2); !LocalDate.of(2012, Month.MAY, 14); dateOfBirth.plusYears(1); !LocalDate date = LocalDate.of(2000, Month.NOVEMBER, 20); LocalDate nextWed = date.with(TemporalAdjusters.next(DayOfWeek.WEDNESDAY));

Groovy could add some operator overloading?

Date / Time API

52

LocalDate.now(); today.with(TemporalAdjusters.lastDayOfMonth()).minusDays(2); !LocalDate.of(2012, Month.MAY, 14); dateOfBirth.plusYears(1); !LocalDate date = LocalDate.of(2000, Month.NOVEMBER, 20); LocalDate nextWed = date.with(TemporalAdjusters.next(DayOfWeek.WEDNESDAY));

Groovy’s date / time handling

53

import static java.util.Calendar.* import groovy.time.* import org.codehaus.groovy.runtime.TimeCategory !def cal = Calendar.instance cal.set(year: 2010, month: JULY, date: 9) !assert FRIDAY == cal[DAY_OF_WEEK] !use (TimeCategory) { 2.years + 3.months + 15.days + 23.minutes + 2.seconds ! 1.week - 1.day new Date() + 6.days ! 3.days.ago new Date() - 3 }

Groovy’s date / time handling

53

import static java.util.Calendar.* import groovy.time.* import org.codehaus.groovy.runtime.TimeCategory !def cal = Calendar.instance cal.set(year: 2010, month: JULY, date: 9) !assert FRIDAY == cal[DAY_OF_WEEK] !use (TimeCategory) { 2.years + 3.months + 15.days + 23.minutes + 2.seconds ! 1.week - 1.day new Date() + 6.days ! 3.days.ago new Date() - 3 }

Groovy could provide the same for Date / Time

Groovy’s date / time handling

53

import static java.util.Calendar.* import groovy.time.* import org.codehaus.groovy.runtime.TimeCategory !def cal = Calendar.instance cal.set(year: 2010, month: JULY, date: 9) !assert FRIDAY == cal[DAY_OF_WEEK] !use (TimeCategory) { 2.years + 3.months + 15.days + 23.minutes + 2.seconds ! 1.week - 1.day new Date() + 6.days ! 3.days.ago new Date() - 3 }

Stream API

map

map

map

map

map

reducereduce reduce

reduce

reduce

map

map

map

map

map

reducereduce reduce

reduce

reduce

Map / filter / reduce explained to

your 6 year old

map

map

map

map

map

reducereduce reduce

reduce

reduce

Stream

56

persons.stream() .filter( p -> p.getAge() < 18 ) .map( p -> p.getName().toUpperCase() ) .sorted() .collect(Collectors.joining(", "));

Groovy’s functional style with the GDK methods

57

persons .findAll { it.getAge() < 18 } .collect { it.name.toUpperCase() } .sort() .joining(", ")

Groovy using streams too!

58

persons.stream() .filter { it.age < 18 } .map { it.name.toUpperCase() } .sorted() .collect(Collectors.joining(", "))

Groovy using streams too!

58

persons.stream() .filter { it.age < 18 } .map { it.name.toUpperCase() } .sorted() .collect(Collectors.joining(", "))

Leveraging closure to « SAM » type coercion

Groovy using streams too!

58

persons.stream() .filter { it.age < 18 } .map { it.name.toUpperCase() } .sorted() .collect(Collectors.joining(", "))

Optional

59

Optional<String> maybeName = Optional.of("Guillaume"); !String result = maybeName.orElse("unknown") !if (maybeName.ifPresent()) { System.out.println(maybeName.get()); } else { System.out.println("unknown"); }

Optional

59

Optional<String> maybeName = Optional.of("Guillaume"); !String result = maybeName.orElse("unknown") !if (maybeName.ifPresent()) { System.out.println(maybeName.get()); } else { System.out.println("unknown"); }

Wrap something that can be potentially null

Optional

59

Optional<String> maybeName = Optional.of("Guillaume"); !String result = maybeName.orElse("unknown") !if (maybeName.ifPresent()) { System.out.println(maybeName.get()); } else { System.out.println("unknown"); }

Optional

59

Optional<String> maybeName = Optional.of("Guillaume"); !String result = maybeName.orElse("unknown") !if (maybeName.ifPresent()) { System.out.println(maybeName.get()); } else { System.out.println("unknown"); }

Force handling the null

value

Optional

59

Optional<String> maybeName = Optional.of("Guillaume"); !String result = maybeName.orElse("unknown") !if (maybeName.ifPresent()) { System.out.println(maybeName.get()); } else { System.out.println("unknown"); }

You know you can customize the truth in Groovy?

You know you can customize the truth in Groovy?

Just implement a custom asBoolean() method!

The law of Groovy Truth

61

The law of Groovy Truth

61

Everything that’s null, empty, zero-sized, equal

to zero is false

The law of Groovy Truth

61

Everything that’s null, empty, zero-sized, equal

to zero is false

Otherwise, it’s true!

?:

Groovy truth, null handling, Elvis with Optional

63

def maybeName = Optional.of("Guillaume") !def result = maybeName ?: "unknown" !if (maybeName) { println maybeName.get() } else { println "unknown" } !maybeName?.toUpperCase()

Groovy truth, null handling, Elvis with Optional

63

def maybeName = Optional.of("Guillaume") !def result = maybeName ?: "unknown" !if (maybeName) { println maybeName.get() } else { println "unknown" } !maybeName?.toUpperCase()

Elvis!

Groovy truth, null handling, Elvis with Optional

63

def maybeName = Optional.of("Guillaume") !def result = maybeName ?: "unknown" !if (maybeName) { println maybeName.get() } else { println "unknown" } !maybeName?.toUpperCase()

Groovy Truth!

Groovy truth, null handling, Elvis with Optional

63

def maybeName = Optional.of("Guillaume") !def result = maybeName ?: "unknown" !if (maybeName) { println maybeName.get() } else { println "unknown" } !maybeName?.toUpperCase()

Safe navigation

Groovy truth, null handling, Elvis with Optional

63

def maybeName = Optional.of("Guillaume") !def result = maybeName ?: "unknown" !if (maybeName) { println maybeName.get() } else { println "unknown" } !maybeName?.toUpperCase()

Interesting discussions on the mailing-list

to further enhance usage of

Optional from Groovy

Groovy truth, null handling, Elvis with Optional

63

def maybeName = Optional.of("Guillaume") !def result = maybeName ?: "unknown" !if (maybeName) { println maybeName.get() } else { println "unknown" } !maybeName?.toUpperCase()

Not Yet Implemented

Groovy truth, null handling, Elvis with Optional

63

def maybeName = Optional.of("Guillaume") !def result = maybeName ?: "unknown" !if (maybeName) { println maybeName.get() } else { println "unknown" } !maybeName?.toUpperCase()

Nashorn

Nashorn

Speak German?

Call JavaScript from Groovy with JSR-223

65

def manager = new ScriptEngineManager() def engine = manager.getEngineByName("nashorn") !

assert engine.eval("{} + []") == 0

Call JavaScript from Groovy with JSR-223

65

def manager = new ScriptEngineManager() def engine = manager.getEngineByName("nashorn") !

assert engine.eval("{} + []") == 0

Sane JavaScript logic :-)

GrooScript — http://grooscript.org/

66

JS

GrooScript — http://grooscript.org/

66

JSGradle & Grails plugins available

Examples available with Ratpack, Node.JS…

Turtles all the way down!

Turtles all the way down!

Full Groovy!

Turtles all the way down!

Full Groovy!

Back to front

Turtles all the way down!

Full Groovy!

Back to front

Front to back

Jackson Pollock

JavaFx… !

!

…the new Swing

GroovyFX

70

import javafx.scene.Scene import static groovyx.javafx.GroovyFX.start !def chamber = ["5 Stelle": 108, "Italia.\nBene commune": 340, "Con Monti per l'Italia": 45, "Berlusconi": 124, "others": 4] !start { stage(title: 'Italian chamber of Deputies', width: 1024, height: 700, visible: true) { Scene s = scene { tilePane { barChart(barGap: 10, categoryGap: 20, title: "Italy's election in February 2013") { series(name: 'Chamber (seats)', data: ['5 Stelle', 17.5, 'Monti', 7.8, 'Bene commune', 55, 'Berlusconi', 19.9]) series(name: 'Senate (seats)', data: ['5 Stelle', 17.4, 'Monti', 6.1, 'Bene commune', 39.1, 'Berlusconi', 37.1]) } pieChart(data: chamber, title: "Chamber of Deputies") } } s.stylesheets.add("Chart.css") } }

GroovyFX

70

import javafx.scene.Scene import static groovyx.javafx.GroovyFX.start !def chamber = ["5 Stelle": 108, "Italia.\nBene commune": 340, "Con Monti per l'Italia": 45, "Berlusconi": 124, "others": 4] !start { stage(title: 'Italian chamber of Deputies', width: 1024, height: 700, visible: true) { Scene s = scene { tilePane { barChart(barGap: 10, categoryGap: 20, title: "Italy's election in February 2013") { series(name: 'Chamber (seats)', data: ['5 Stelle', 17.5, 'Monti', 7.8, 'Bene commune', 55, 'Berlusconi', 19.9]) series(name: 'Senate (seats)', data: ['5 Stelle', 17.4, 'Monti', 6.1, 'Bene commune', 39.1, 'Berlusconi', 37.1]) } pieChart(data: chamber, title: "Chamber of Deputies") } } s.stylesheets.add("Chart.css") } }

Groovy builder to the rescue!

© 2014 SpringOne 2GX. All rights reserved. Do not distribute without permission.

Beyond Java

© 2014 SpringOne 2GX. All rights reserved. Do not distribute without permission.

Easy scripting

Scripting

73

@Grab('net.sourceforge.htmlcleaner:htmlcleaner:2.4') import org.htmlcleaner.* !def src = new File('html').toPath() def dst = new File('asciidoc').toPath() !def cleaner = new HtmlCleaner() def props = cleaner.properties props.translateSpecialEntities = false def serializer = new SimpleHtmlSerializer(props) !src.toFile().eachFileRecurse { f -> def relative = src.relativize(f.toPath()) def target = dst.resolve(relative) if (f.isDirectory()) { target.toFile().mkdir() } else if (f.name.endsWith('.html')) { def tmpHtml = File.createTempFile('clean', 'html') println "Converting $relative" def result = cleaner.clean(f) result.traverse({ tagNode, htmlNode -> tagNode?.attributes?.remove 'class' if ('td' == tagNode?.name || 'th'==tagNode?.name) { tagNode.name='td' String txt = tagNode.text tagNode.removeAllChildren() tagNode.insertChild(0, new ContentNode(txt)) } true } as TagNodeVisitor) serializer.writeToFile( result, tmpHtml.absolutePath, "utf-8" ) "pandoc -f html -t asciidoc -R -S --normalize -s $tmpHtml -o ${target}.adoc" .execute().waitFor() tmpHtml.delete() } }

<html/>

AsciiDoctor

Ant scripting

74

@Grab('net.sourceforge.htmlcleaner:htmlcleaner:2.4') import org.htmlcleaner.* !def src = new File('html').toPath() def dst = new File('asciidoc').toPath() !def cleaner = new HtmlCleaner() def props = cleaner.properties props.translateSpecialEntities = false def serializer = new SimpleHtmlSerializer(props) !src.toFile().eachFileRecurse { f -> def relative = src.relativize(f.toPath()) def target = dst.resolve(relative) if (f.isDirectory()) { target.toFile().mkdir() } else if (f.name.endsWith('.html')) { def tmpHtml = File.createTempFile('clean', 'html') println "Converting $relative" def result = cleaner.clean(f) result.traverse({ tagNode, htmlNode -> tagNode?.attributes?.remove 'class' if ('td' == tagNode?.name || 'th'==tagNode?.name) { tagNode.name='td' String txt = tagNode.text

Ant scripting

74

@Grab('net.sourceforge.htmlcleaner:htmlcleaner:2.4') import org.htmlcleaner.* !def src = new File('html').toPath() def dst = new File('asciidoc').toPath() !def cleaner = new HtmlCleaner() def props = cleaner.properties props.translateSpecialEntities = false def serializer = new SimpleHtmlSerializer(props) !src.toFile().eachFileRecurse { f -> def relative = src.relativize(f.toPath()) def target = dst.resolve(relative) if (f.isDirectory()) { target.toFile().mkdir() } else if (f.name.endsWith('.html')) { def tmpHtml = File.createTempFile('clean', 'html') println "Converting $relative" def result = cleaner.clean(f) result.traverse({ tagNode, htmlNode -> tagNode?.attributes?.remove 'class' if ('td' == tagNode?.name || 'th'==tagNode?.name) { tagNode.name='td' String txt = tagNode.text

Use @Grab to download the htmlcleaner library

Ant scripting

74

@Grab('net.sourceforge.htmlcleaner:htmlcleaner:2.4') import org.htmlcleaner.* !def src = new File('html').toPath() def dst = new File('asciidoc').toPath() !def cleaner = new HtmlCleaner() def props = cleaner.properties props.translateSpecialEntities = false def serializer = new SimpleHtmlSerializer(props) !src.toFile().eachFileRecurse { f -> def relative = src.relativize(f.toPath()) def target = dst.resolve(relative) if (f.isDirectory()) { target.toFile().mkdir() } else if (f.name.endsWith('.html')) { def tmpHtml = File.createTempFile('clean', 'html') println "Converting $relative" def result = cleaner.clean(f) result.traverse({ tagNode, htmlNode -> tagNode?.attributes?.remove 'class' if ('td' == tagNode?.name || 'th'==tagNode?.name) { tagNode.name='td' String txt = tagNode.text

Ant scripting

74

@Grab('net.sourceforge.htmlcleaner:htmlcleaner:2.4') import org.htmlcleaner.* !def src = new File('html').toPath() def dst = new File('asciidoc').toPath() !def cleaner = new HtmlCleaner() def props = cleaner.properties props.translateSpecialEntities = false def serializer = new SimpleHtmlSerializer(props) !src.toFile().eachFileRecurse { f -> def relative = src.relativize(f.toPath()) def target = dst.resolve(relative) if (f.isDirectory()) { target.toFile().mkdir() } else if (f.name.endsWith('.html')) { def tmpHtml = File.createTempFile('clean', 'html') println "Converting $relative" def result = cleaner.clean(f) result.traverse({ tagNode, htmlNode -> tagNode?.attributes?.remove 'class' if ('td' == tagNode?.name || 'th'==tagNode?.name) { tagNode.name='td' String txt = tagNode.text

Setup HtmlCleaner

Ant scripting

74

@Grab('net.sourceforge.htmlcleaner:htmlcleaner:2.4') import org.htmlcleaner.* !def src = new File('html').toPath() def dst = new File('asciidoc').toPath() !def cleaner = new HtmlCleaner() def props = cleaner.properties props.translateSpecialEntities = false def serializer = new SimpleHtmlSerializer(props) !src.toFile().eachFileRecurse { f -> def relative = src.relativize(f.toPath()) def target = dst.resolve(relative) if (f.isDirectory()) { target.toFile().mkdir() } else if (f.name.endsWith('.html')) { def tmpHtml = File.createTempFile('clean', 'html') println "Converting $relative" def result = cleaner.clean(f) result.traverse({ tagNode, htmlNode -> tagNode?.attributes?.remove 'class' if ('td' == tagNode?.name || 'th'==tagNode?.name) { tagNode.name='td' String txt = tagNode.text

Ant scripting

74

@Grab('net.sourceforge.htmlcleaner:htmlcleaner:2.4') import org.htmlcleaner.* !def src = new File('html').toPath() def dst = new File('asciidoc').toPath() !def cleaner = new HtmlCleaner() def props = cleaner.properties props.translateSpecialEntities = false def serializer = new SimpleHtmlSerializer(props) !src.toFile().eachFileRecurse { f -> def relative = src.relativize(f.toPath()) def target = dst.resolve(relative) if (f.isDirectory()) { target.toFile().mkdir() } else if (f.name.endsWith('.html')) { def tmpHtml = File.createTempFile('clean', 'html') println "Converting $relative" def result = cleaner.clean(f) result.traverse({ tagNode, htmlNode -> tagNode?.attributes?.remove 'class' if ('td' == tagNode?.name || 'th'==tagNode?.name) { tagNode.name='td' String txt = tagNode.text

Recursively find all the files to transform

Ant scripting

74

@Grab('net.sourceforge.htmlcleaner:htmlcleaner:2.4') import org.htmlcleaner.* !def src = new File('html').toPath() def dst = new File('asciidoc').toPath() !def cleaner = new HtmlCleaner() def props = cleaner.properties props.translateSpecialEntities = false def serializer = new SimpleHtmlSerializer(props) !src.toFile().eachFileRecurse { f -> def relative = src.relativize(f.toPath()) def target = dst.resolve(relative) if (f.isDirectory()) { target.toFile().mkdir() } else if (f.name.endsWith('.html')) { def tmpHtml = File.createTempFile('clean', 'html') println "Converting $relative" def result = cleaner.clean(f) result.traverse({ tagNode, htmlNode -> tagNode?.attributes?.remove 'class' if ('td' == tagNode?.name || 'th'==tagNode?.name) { tagNode.name='td' String txt = tagNode.text

Ant scripting

75

def props = cleaner.properties props.translateSpecialEntities = false def serializer = new SimpleHtmlSerializer(props) !src.toFile().eachFileRecurse { f -> def relative = src.relativize(f.toPath()) def target = dst.resolve(relative) if (f.isDirectory()) { target.toFile().mkdir() } else if (f.name.endsWith('.html')) { def tmpHtml = File.createTempFile('clean', 'html') println "Converting $relative" def result = cleaner.clean(f) result.traverse({ tagNode, htmlNode -> tagNode?.attributes?.remove 'class' if ('td' == tagNode?.name || 'th'==tagNode?.name) { tagNode.name='td' String txt = tagNode.text tagNode.removeAllChildren() tagNode.insertChild(0, new ContentNode(txt)) } true } as TagNodeVisitor) serializer.writeToFile( result, tmpHtml.absolutePath, "utf-8" ) "pandoc -f html -t asciidoc -R -S --normalize -s $tmpHtml -o ${target}.adoc"

Ant scripting

75

def props = cleaner.properties props.translateSpecialEntities = false def serializer = new SimpleHtmlSerializer(props) !src.toFile().eachFileRecurse { f -> def relative = src.relativize(f.toPath()) def target = dst.resolve(relative) if (f.isDirectory()) { target.toFile().mkdir() } else if (f.name.endsWith('.html')) { def tmpHtml = File.createTempFile('clean', 'html') println "Converting $relative" def result = cleaner.clean(f) result.traverse({ tagNode, htmlNode -> tagNode?.attributes?.remove 'class' if ('td' == tagNode?.name || 'th'==tagNode?.name) { tagNode.name='td' String txt = tagNode.text tagNode.removeAllChildren() tagNode.insertChild(0, new ContentNode(txt)) } true } as TagNodeVisitor) serializer.writeToFile( result, tmpHtml.absolutePath, "utf-8" ) "pandoc -f html -t asciidoc -R -S --normalize -s $tmpHtml -o ${target}.adoc"

Clean the HTML

Ant scripting

75

def props = cleaner.properties props.translateSpecialEntities = false def serializer = new SimpleHtmlSerializer(props) !src.toFile().eachFileRecurse { f -> def relative = src.relativize(f.toPath()) def target = dst.resolve(relative) if (f.isDirectory()) { target.toFile().mkdir() } else if (f.name.endsWith('.html')) { def tmpHtml = File.createTempFile('clean', 'html') println "Converting $relative" def result = cleaner.clean(f) result.traverse({ tagNode, htmlNode -> tagNode?.attributes?.remove 'class' if ('td' == tagNode?.name || 'th'==tagNode?.name) { tagNode.name='td' String txt = tagNode.text tagNode.removeAllChildren() tagNode.insertChild(0, new ContentNode(txt)) } true } as TagNodeVisitor) serializer.writeToFile( result, tmpHtml.absolutePath, "utf-8" ) "pandoc -f html -t asciidoc -R -S --normalize -s $tmpHtml -o ${target}.adoc"

Ant scripting

75

def props = cleaner.properties props.translateSpecialEntities = false def serializer = new SimpleHtmlSerializer(props) !src.toFile().eachFileRecurse { f -> def relative = src.relativize(f.toPath()) def target = dst.resolve(relative) if (f.isDirectory()) { target.toFile().mkdir() } else if (f.name.endsWith('.html')) { def tmpHtml = File.createTempFile('clean', 'html') println "Converting $relative" def result = cleaner.clean(f) result.traverse({ tagNode, htmlNode -> tagNode?.attributes?.remove 'class' if ('td' == tagNode?.name || 'th'==tagNode?.name) { tagNode.name='td' String txt = tagNode.text tagNode.removeAllChildren() tagNode.insertChild(0, new ContentNode(txt)) } true } as TagNodeVisitor) serializer.writeToFile( result, tmpHtml.absolutePath, "utf-8" ) "pandoc -f html -t asciidoc -R -S --normalize -s $tmpHtml -o ${target}.adoc"

Some more clean-up

Ant scripting

75

def props = cleaner.properties props.translateSpecialEntities = false def serializer = new SimpleHtmlSerializer(props) !src.toFile().eachFileRecurse { f -> def relative = src.relativize(f.toPath()) def target = dst.resolve(relative) if (f.isDirectory()) { target.toFile().mkdir() } else if (f.name.endsWith('.html')) { def tmpHtml = File.createTempFile('clean', 'html') println "Converting $relative" def result = cleaner.clean(f) result.traverse({ tagNode, htmlNode -> tagNode?.attributes?.remove 'class' if ('td' == tagNode?.name || 'th'==tagNode?.name) { tagNode.name='td' String txt = tagNode.text tagNode.removeAllChildren() tagNode.insertChild(0, new ContentNode(txt)) } true } as TagNodeVisitor) serializer.writeToFile( result, tmpHtml.absolutePath, "utf-8" ) "pandoc -f html -t asciidoc -R -S --normalize -s $tmpHtml -o ${target}.adoc"

Ant scripting

76

def target = dst.resolve(relative) if (f.isDirectory()) { target.toFile().mkdir() } else if (f.name.endsWith('.html')) { def tmpHtml = File.createTempFile('clean', 'html') println "Converting $relative" def result = cleaner.clean(f) result.traverse({ tagNode, htmlNode -> tagNode?.attributes?.remove 'class' if ('td' == tagNode?.name || 'th'==tagNode?.name) { tagNode.name='td' String txt = tagNode.text tagNode.removeAllChildren() tagNode.insertChild(0, new ContentNode(txt)) } true } as TagNodeVisitor) serializer.writeToFile( result, tmpHtml.absolutePath, "utf-8" ) "pandoc -f html -t asciidoc -R -S --normalize -s $tmpHtml -o ${target}.adoc" .execute().waitFor() tmpHtml.delete() } }

Ant scripting

76

def target = dst.resolve(relative) if (f.isDirectory()) { target.toFile().mkdir() } else if (f.name.endsWith('.html')) { def tmpHtml = File.createTempFile('clean', 'html') println "Converting $relative" def result = cleaner.clean(f) result.traverse({ tagNode, htmlNode -> tagNode?.attributes?.remove 'class' if ('td' == tagNode?.name || 'th'==tagNode?.name) { tagNode.name='td' String txt = tagNode.text tagNode.removeAllChildren() tagNode.insertChild(0, new ContentNode(txt)) } true } as TagNodeVisitor) serializer.writeToFile( result, tmpHtml.absolutePath, "utf-8" ) "pandoc -f html -t asciidoc -R -S --normalize -s $tmpHtml -o ${target}.adoc" .execute().waitFor() tmpHtml.delete() } }

Write the result

Ant scripting

76

def target = dst.resolve(relative) if (f.isDirectory()) { target.toFile().mkdir() } else if (f.name.endsWith('.html')) { def tmpHtml = File.createTempFile('clean', 'html') println "Converting $relative" def result = cleaner.clean(f) result.traverse({ tagNode, htmlNode -> tagNode?.attributes?.remove 'class' if ('td' == tagNode?.name || 'th'==tagNode?.name) { tagNode.name='td' String txt = tagNode.text tagNode.removeAllChildren() tagNode.insertChild(0, new ContentNode(txt)) } true } as TagNodeVisitor) serializer.writeToFile( result, tmpHtml.absolutePath, "utf-8" ) "pandoc -f html -t asciidoc -R -S --normalize -s $tmpHtml -o ${target}.adoc" .execute().waitFor() tmpHtml.delete() } }

Ant scripting

76

def target = dst.resolve(relative) if (f.isDirectory()) { target.toFile().mkdir() } else if (f.name.endsWith('.html')) { def tmpHtml = File.createTempFile('clean', 'html') println "Converting $relative" def result = cleaner.clean(f) result.traverse({ tagNode, htmlNode -> tagNode?.attributes?.remove 'class' if ('td' == tagNode?.name || 'th'==tagNode?.name) { tagNode.name='td' String txt = tagNode.text tagNode.removeAllChildren() tagNode.insertChild(0, new ContentNode(txt)) } true } as TagNodeVisitor) serializer.writeToFile( result, tmpHtml.absolutePath, "utf-8" ) "pandoc -f html -t asciidoc -R -S --normalize -s $tmpHtml -o ${target}.adoc" .execute().waitFor() tmpHtml.delete() } }

Call an external process to convert and wait for its execution

Ant scripting

76

def target = dst.resolve(relative) if (f.isDirectory()) { target.toFile().mkdir() } else if (f.name.endsWith('.html')) { def tmpHtml = File.createTempFile('clean', 'html') println "Converting $relative" def result = cleaner.clean(f) result.traverse({ tagNode, htmlNode -> tagNode?.attributes?.remove 'class' if ('td' == tagNode?.name || 'th'==tagNode?.name) { tagNode.name='td' String txt = tagNode.text tagNode.removeAllChildren() tagNode.insertChild(0, new ContentNode(txt)) } true } as TagNodeVisitor) serializer.writeToFile( result, tmpHtml.absolutePath, "utf-8" ) "pandoc -f html -t asciidoc -R -S --normalize -s $tmpHtml -o ${target}.adoc" .execute().waitFor() tmpHtml.delete() } }

© 2014 SpringOne 2GX. All rights reserved. Do not distribute without permission.

Android

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

78

New York Times — Getting Groovy with Android

79

New York Times — Getting Groovy with Android

79

http://bit.ly/nyt-groovy

What does NYT likes about Groovy on Android?

• No Java 8, no lambda on Android…

80

Func0 func = new Func0<string>() { @Override public String call() { return "my content"; } }; Async.start(func);

What does NYT likes about Groovy on Android?

• No Java 8, no lambda on Android…

81

!

!

!

!

!

!

Async.start { "my content" }

What does NYT likes about Groovy on Android?

• No Java 8, no lambda on Android…

81

!

!

!

!

!

!

Async.start { "my content" }

Good bye annonymous inner classes!

What does NYT likes about Groovy on Android?

!

• Groovy code more concise and more readable !

• but just as type-safe as needed!(with @TypeChecked) !

• but just as fast as needed!(with @CompileStatic)

82

Android support

83

Android support

83

Android support

83

Source code available:https://github.com/melix/gr8confagenda

To know all about Android support

84

Groovy & Android, a winning pair? by Cédric Champeau Thu 12:45pm / Trinity 3

© 2014 SpringOne 2GX. All rights reserved. Do not distribute without permission.

A rich Groovy ecosystem

Grails — web framework

86

@Grab("com.h2database:h2:1.3.173") import grails.persistence.* !

@Entity @Resource(uri='/books') class Book { String title }

Grails — web framework

86

@Grab("com.h2database:h2:1.3.173") import grails.persistence.* !

@Entity @Resource(uri='/books') class Book { String title }

One class, one command, and you’ve got a full REST

CRUD application!

Ratpack — web framework

87

@GrabResolver("https://oss.jfrog.org/artifactory/repo") @Grab("org.ratpack-framework:ratpack-groovy:0.9.8") import static org.ratpackframework.groovy.RatpackScript.ratpack import static org.ratpackframework.groovy.Template.groovyTemplate !ratpack { handlers { get { response.send "Welcome!" } ! get("date") { render groovyTemplate("date.html") } ! assets "public" } }

Ratpack — web framework

87

@GrabResolver("https://oss.jfrog.org/artifactory/repo") @Grab("org.ratpack-framework:ratpack-groovy:0.9.8") import static org.ratpackframework.groovy.RatpackScript.ratpack import static org.ratpackframework.groovy.Template.groovyTemplate !ratpack { handlers { get { response.send "Welcome!" } ! get("date") { render groovyTemplate("date.html") } ! assets "public" } }

Lightweight Netty-based web application toolkit

@ArtifactProviderFor(GriffonModel) class ConsoleModel { String scriptSource @Observable Object scriptResult @Observable boolean enabled = true }

Griffon — rich desktop applications

88

@ArtifactProviderFor(GriffonModel) class ConsoleModel { String scriptSource @Observable Object scriptResult @Observable boolean enabled = true }

Griffon — rich desktop applications

88

Model

@ArtifactProviderFor(GriffonModel) class ConsoleModel { String scriptSource @Observable Object scriptResult @Observable boolean enabled = true }

Griffon — rich desktop applications

88

Model

@ArtifactProviderFor(GriffonController) class ConsoleController { def model ! @Inject Evaluator evaluator ! void executeScript() { model.enabled = false def result try { result = evaluator.evaluate(model.scriptSource) } finally { model.enabled = true model.scriptResult = result } } }

Controller

@ArtifactProviderFor(GriffonModel) class ConsoleModel { String scriptSource @Observable Object scriptResult @Observable boolean enabled = true }

Griffon — rich desktop applications

88

Model

@ArtifactProviderFor(GriffonController) class ConsoleController { def model ! @Inject Evaluator evaluator ! void executeScript() { model.enabled = false def result try { result = evaluator.evaluate(model.scriptSource) } finally { model.enabled = true model.scriptResult = result } } }

Controller

application(title: application.configuration['application.title'], pack: true, locationByPlatform: true, id: 'mainWindow', iconImage: imageIcon('/griffon-icon-48x48.png').image, iconImages: [imageIcon('/griffon-icon-48x48.png').image, imageIcon('/griffon-icon-32x32.png').image, imageIcon('/griffon-icon-16x16.png').image]) { panel(border: emptyBorder(6)) { borderLayout() scrollPane(constraints: CENTER) { textArea(text: bind(target: model, 'scriptSource'), enabled: bind { model.enabled }, columns: 40, rows: 10) } ! hbox(constraints: SOUTH) { button(executeScriptAction) hstrut(5) label('Result:') hstrut(5) textField(editable: false, text: bind { model.scriptResult }) } } }

View

Spock — unit testing & specification

89

@Grab('org.spockframework:spock-core:0.7-groovy-2.0') import spock.lang.* !class MathSpec extends Specification { def "maximum of two numbers"() { expect: Math.max(a, b) == c ! where: a | b || c 1 | 3 || 3 7 | 4 || 7 0 | 0 || 0 } }

Spock — unit testing & specification

89

@Grab('org.spockframework:spock-core:0.7-groovy-2.0') import spock.lang.* !class MathSpec extends Specification { def "maximum of two numbers"() { expect: Math.max(a, b) == c ! where: a | b || c 1 | 3 || 3 7 | 4 || 7 0 | 0 || 0 } }

Readable & concise expectations

Spock — unit testing & specification

89

@Grab('org.spockframework:spock-core:0.7-groovy-2.0') import spock.lang.* !class MathSpec extends Specification { def "maximum of two numbers"() { expect: Math.max(a, b) == c ! where: a | b || c 1 | 3 || 3 7 | 4 || 7 0 | 0 || 0 } }

Readable & concise expectations

Awesome data-driven tests with a wiki-like notation

Geb — browser automation

90

import geb.Browser !Browser.drive { go "http://myapp.com/login" ! assert $("h1").text() == "Please Login" ! $("form.login").with { username = "admin" password = "password" login().click() } ! assert $("h1").text() == "Admin Section" }

Geb — browser automation

90

import geb.Browser !Browser.drive { go "http://myapp.com/login" ! assert $("h1").text() == "Please Login" ! $("form.login").with { username = "admin" password = "password" login().click() } ! assert $("h1").text() == "Admin Section" }

Drive your browser

Geb — browser automation

90

import geb.Browser !Browser.drive { go "http://myapp.com/login" ! assert $("h1").text() == "Please Login" ! $("form.login").with { username = "admin" password = "password" login().click() } ! assert $("h1").text() == "Admin Section" }

Drive your browser

JQuery-like selectors

Geb — browser automation

90

import geb.Browser !Browser.drive { go "http://myapp.com/login" ! assert $("h1").text() == "Please Login" ! $("form.login").with { username = "admin" password = "password" login().click() } ! assert $("h1").text() == "Admin Section" }

Drive your browser

JQuery-like selectors

Fill & submit forms

Gradle — build automation

91

apply plugin: 'java' apply plugin: 'eclipse' !sourceCompatibility = 1.5 version = '1.0' jar { manifest { attributes 'Implementation-Title': 'Gradle Quickstart' } } !repositories { mavenCentral() } !dependencies { compile ‘commons-collections:commons-collections:3.2’ testCompile 'junit:junit:4.+' } !uploadArchives { repositories { flatDir { dirs 'repos' } } }

Gradle — build automation

91

apply plugin: 'java' apply plugin: 'eclipse' !sourceCompatibility = 1.5 version = '1.0' jar { manifest { attributes 'Implementation-Title': 'Gradle Quickstart' } } !repositories { mavenCentral() } !dependencies { compile ‘commons-collections:commons-collections:3.2’ testCompile 'junit:junit:4.+' } !uploadArchives { repositories { flatDir { dirs 'repos' } } }

Powerful and readable DSL for automating your builds

and deployments

GPars — concurrency / parallelism / async / …

92

import static groovyx.gpars.actor.Actors.actor !def decryptor = actor { loop { react { message -> if (message instanceof String) reply message.reverse() else stop() } } } !def console = actor { decryptor.send 'lellarap si yvoorG' react { println 'Decrypted message: ${it}' decryptor.send false } } ![decryptor, console]*.join()

GPars — concurrency / parallelism / async / …

92

import static groovyx.gpars.actor.Actors.actor !def decryptor = actor { loop { react { message -> if (message instanceof String) reply message.reverse() else stop() } } } !def console = actor { decryptor.send 'lellarap si yvoorG' react { println 'Decrypted message: ${it}' decryptor.send false } } ![decryptor, console]*.join()

Actors…

GPars — concurrency / parallelism / async / …

92

import static groovyx.gpars.actor.Actors.actor !def decryptor = actor { loop { react { message -> if (message instanceof String) reply message.reverse() else stop() } } } !def console = actor { decryptor.send 'lellarap si yvoorG' react { println 'Decrypted message: ${it}' decryptor.send false } } ![decryptor, console]*.join()

Actors…

But also:Dataflow concurrency, CSP, agents, concurrent collection processing,

fork / join, composable async functions, STM

© 2014 SpringOne 2GX. All rights reserved. Do not distribute without permission.

Groovy modules

Groovy modules

• Ant scripting • JMX • JSON • Servlet • Swing • SQL • Templating • Testing • XML

94

Groovy modules

• Ant scripting • JMX • JSON • Servlet • Swing • SQL • Templating • Testing • XML

95

Ant + XML

96

def writer = new StringWriter() def mkp = new MarkupBuilder(writer) !mkp.html { head { title 'Build notification' } body { p 'Your build was successful' } } !new AntBuilder().mail(mailhost: 'localhost', messagemimetype: 'text/html', subject: 'Build successful') { ! from address: 'ci@mycomp.com' to address: 'me@mycomp.com' message writer attchments { fileset(dir: 'dist') { include name: '**/logs*.txt' } } }

Ant + XML

96

def writer = new StringWriter() def mkp = new MarkupBuilder(writer) !mkp.html { head { title 'Build notification' } body { p 'Your build was successful' } } !new AntBuilder().mail(mailhost: 'localhost', messagemimetype: 'text/html', subject: 'Build successful') { ! from address: 'ci@mycomp.com' to address: 'me@mycomp.com' message writer attchments { fileset(dir: 'dist') { include name: '**/logs*.txt' } } }

Generate some HTML with the XML support

Ant + XML

96

def writer = new StringWriter() def mkp = new MarkupBuilder(writer) !mkp.html { head { title 'Build notification' } body { p 'Your build was successful' } } !new AntBuilder().mail(mailhost: 'localhost', messagemimetype: 'text/html', subject: 'Build successful') { ! from address: 'ci@mycomp.com' to address: 'me@mycomp.com' message writer attchments { fileset(dir: 'dist') { include name: '**/logs*.txt' } } }

Generate some HTML with the XML support

Use the Ant builder and the mail task

Ant + XML

96

def writer = new StringWriter() def mkp = new MarkupBuilder(writer) !mkp.html { head { title 'Build notification' } body { p 'Your build was successful' } } !new AntBuilder().mail(mailhost: 'localhost', messagemimetype: 'text/html', subject: 'Build successful') { ! from address: 'ci@mycomp.com' to address: 'me@mycomp.com' message writer attchments { fileset(dir: 'dist') { include name: '**/logs*.txt' } } }

Generate some HTML with the XML support

Use the Ant builder and the mail task

Use the Ant’s fileset

JSON support — creating JSON

97

import groovy.json.* !def json = new JsonBuilder() json.person { name 'Guillaume' age 37 daughters 'Marion', 'Erine' address { street '1 Main Street' zip 75001 city 'Paris' } }

JSON support — creating JSON

97

import groovy.json.* !def json = new JsonBuilder() json.person { name 'Guillaume' age 37 daughters 'Marion', 'Erine' address { street '1 Main Street' zip 75001 city 'Paris' } }

{ "person": { "name": "Guillaume", "age": 37, "daughters": [ "Marion", "Erine" ], "address": { "street": "1 Main Street", "zip": 75001, "city": "Paris" } } }

JSON support — parsing JSON

98

import groovy.json.* !def url = "https://api.github.com/repos/groovy/groovy-core/commits" !def commits = new JsonSlurper().parseText(url.toURL().text) !assert commits[0].commit.author.name == 'Cedric Champeau'

JSON support — parsing JSON

98

import groovy.json.* !def url = "https://api.github.com/repos/groovy/groovy-core/commits" !def commits = new JsonSlurper().parseText(url.toURL().text) !assert commits[0].commit.author.name == 'Cedric Champeau'

The power of a dynamic language!

Template module — new 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 99

Template module — new 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 99

Spring Boot approved

Markup template engine — the idea

100

cars { cars.each { car(make: it.make, name: it.name) } }

Markup template engine — the idea

100

cars { cars.each { car(make: it.make, name: it.name) } }

Your template

Markup template engine — the idea

100

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

100

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

100

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

100

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

100

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

101

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)

© 2014 SpringOne 2GX. All rights reserved. Do not distribute without permission.

Summary

Back to our original question…

103

Do we still need Groovy now that we

have Java 8?

Longer answer: Yes, because…

• You can benefit from Java 8 in Groovy

105

Synergy the whole is greater than the sum of the parts

Longer answer: Yes, because…

• Groovy goes beyond what Java 8 offers

106

BeyondGroovy always

tries to add something to the table

Questions still open: Syntax support for…

• lambdas • not necessarily,

(confusing / duplication) !

• method references • enhance method closures • or replace them with

method references !

• interface default methods • yes: traits methods aren’t

default methods

• repeated annotations • yes: not urgent • but less boilerplate is good !

• annotations on type • yes: opens up new

possibilities for targets of local AST transformation

!

• interface static methods • yes: for Java compatibility

107

Further possible API enhancements

• Make Optional Groovy-friendly • with regards to Groovy Truth • accessing the wrapped value !

• More Groovy methods for… • NIO • Streams • Date / time !

• Operator overloading for Date / time • for arithmetics on instants and durations

108

Further possible API enhancements

• Make Optional Groovy-friendly • with regards to Groovy Truth • accessing the wrapped value !

• More Groovy methods for… • NIO • Streams • Date / time !

• Operator overloading for Date / time • for arithmetics on instants and durations

108

Community feedback &

contributions welcome!

More Java 8 coverage

109

Java 8 language capabilities by V. Subramaniam Thu 10:30pm / D.Ball.G

More Java 8 coverage

110

How to get Groovy with Java 8 by Peter Ledbrook Thu 10:30pm / Trinity 3

Java 8 in Action

!

• By Urma, Fusco and Mycrof • Plublished by Manning • http://www.manning.com/urma/

111

© 2014 SpringOne 2GX. All rights reserved. Do not distribute without permission.

Q & A

Image credits

• Question mark • http://www.mynamesnotmommy.com/wp-content/uploads/2013/05/question-mark.png

• Get out! • http://static.comicvine.com/uploads/original/11/117995/3772037-0075368930-27616.jpg

• Yes • http://soloprpro.com/wp-content/uploads/2013/08/yes.jpg

• Synergy • http://www.wildblueberries.com/wp-content/uploads/blogger/_YhH8fDK5-kU/S_5kYWwgAbI/AAAAAAAAAKU/JQ_-ISfT9KY/

s1600/teamwork.jpg • Buzz Lightyear

• http://www.disneypictures.net/data/media/202/Buzz_Lightyear_hd.jpg • Start wars spaceship

• http://swc.fs2downloads.com/media/screenshots/Support_Trans/Shuttle/lambda003.jpg • Lambda character

• http://lambda.ninjackaton.ninja-squad.com/images/lambda.png • Man clock

• http://3.bp.blogspot.com/-7hLQ9tnmA84/TuTIoLRLMTI/AAAAAAAABWM/g7ahyLCRjJQ/s1600/Harold+Lloyd+Safety+Last.jpg • Stream

• http://wallpaperswide.com/forest_stream-wallpapers.html • Nashorn (rhino)

• http://2010sdafrika.files.wordpress.com/2012/07/hi_257587-nashorn-c-naturepl-com-mark-carwardine-wwf-canon.jpg 114

Image credits

• Brain • http://www.semel.ucla.edu/sites/all/files/users/user-412/dreamstime_xxl_17754591%20(2).jpg

• Many thanks • http://www.trys.ie/wp-content/uploads/2013/06/many-thanks.jpg

• Swing • http://makemesomethingspecial.co.uk/wp-content/uploads/2012/10/Solid-Oak-Handmade-Spliced-Swing-With-Personalised-

Engraving-10867.jpg • Disclaimer

• http://3.bp.blogspot.com/-RGnBpjXTCQA/Tj2h_JsLigI/AAAAAAAABbg/AB5ZZYzuE5w/s1600/disclaimer.jpg • Hammer / justice / truth

• http://www.bombayrealty.in/images/disclaimer.jpg • Law

• http://www.permanentmakeupbymv.com/wp-content/uploads/2014/07/law-2.jpg • Glasses / readable

• http://a.fastcompany.net/multisite_files/coexist/imagecache/1280/poster/2013/02/1681393-poster-1280-responsive-eye-chart.jpg • We need you

• http://www.bostonbreakerssoccer.com/imgs/ABOUT/volopps/we%20need%20you.JPG

115

Image credits

• Jackson Pollock • http://www.ibiblio.org/wm/paint/auth/pollock/pollock.number-8.jpg

• Turtles • http://33.media.tumblr.com/77095e3a37acb2272133c405b1f7ba54/tumblr_myfydjNgXJ1s20kxvo1_1280.jpg

• Annotations • http://3.bp.blogspot.com/-f94n9BHko_s/T35ELs7nYvI/AAAAAAAAAKg/qe06LRPH9U4/s1600/IMG_1721.JPG

• Builders • http://detroittraining.com/wp-content/uploads/Construction-Women2.jpg

• Sandwich ingredients • http://www.fromages-de-terroirs.com/IMG/MEULE_DETOUREE_72_DPI_-2.jpg • http://eboutique-hebergement.orange-business.com/WebRoot/Orange/Shops/Madeinalsace/4B02/6320/943E/DB4F/DDBF/

0A0A/33E8/4BC8/iStock_000008775559XSmall.jpg • http://www.cmonprimeur.fr/images/25834-vegetable-pictures%5B1%5D.jpg • http://1.bp.blogspot.com/-27UoqYeYtY4/T4PAr4zGSnI/AAAAAAAAA3s/lleE-NOh0LE/s1600/IMG_1528.JPG • http://www.growingpatch.com/wp-content/uploads/2014/05/tomato-9.jpg • http://vitaminsandhealthsupplements.com/wp-content/uploads/2013/08/fresh-sliced-tomato.jpg • http://2.bp.blogspot.com/-3pPmRhBHv9s/T3D-EtLlN1I/AAAAAAAAAgg/Y5oTM84nGb8/s1600/cochon+2.jpg • http://www.salamarket.fr/wp-content/uploads/steak-hach%C3%A9.jpg • http://www.quinzanisbakery.com/images/bread-vienna.jpg • http://www.saucissonvaudois.qc.ca/images/produits/Jambon_blanc.jpg • http://www.audion.com/system/public/categories/125/images/bread-sandwich.jpg 116