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Introduction to

12/13/2011

Prepared by:Vincent Schwarzer, Chih-Hung Hsieh

Java Enterprise Application Development

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Structure

1. The history of Groovy

2. What is Groovy?Features & Strengths

4. Groovy vs. Java OOP

3. Groovy Builder

5. Common use cases

6. Short example

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The history of Groovy

Several versions released between 2004 and 2006

James Strachan started developing Groovy in 2003

Released final version called Groovy 1.0 in 2007

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What is Groovy?

• An agile and dynamic language for the JVM

• Builds upon the strength of Java

Additional power features inspired by languageslike Ruby, Python and SmallTalk

• Almost zero learning curve for Java Developers

• Seamlessly integrates with all existing Java classes and libraries• You can use it anywhere you can use Java

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Features & Strengths

// old school Java code, but also valid Groovy codeSystem.out.println("Hello, world!");

// idiomatic Groovyprintln "Hello, world!"

// dynamic variable definitiondef name = “Peter"

// GString featuring string interpolationprintln "Hello, $name" // => "Hello, Peter"

// statically typed variableString songName = "Coding in the Name of"

println "Now playing - $songName"

String multiline = """this is a multilinestring. There is not need to embednewline characters in it"""

println multiline

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Features & Strengths

// method definitiondef greet(name) { println "Hello, $name!"}

// method invocationgreet “Peter"greet(“Peter“)

// a list def beers = [“Becks", “Corona", “Budweiser", “Heineken"]

// list access println "My favourite beer is ${beers[1]}“for (i in beers) { println i }

// imports can appear anywhere and support the creation of aliases import static java.util.Calendar.getInstance as now import java.sql.Date as SDate

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Groovy Builder

one use for builders is the generation of markup:

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Groovy Builder

Result:

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Groovy vs. Java

Similar capabilities to Java:

Define classes, interfaces, enums, annotations

Differences to Java:

Classes (and interfaces etc.) public by default Methods public by default Property support within classes (auto-setters/getters)

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Common use cases

Web application development

scripting

Rapid prototyping

As a proof on concept

Exploratory Programming

Test class / method capabilities

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Thank You