Groovy Programing Language

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After this topic?Web development with Grails

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Groovy Programming Language

What is Groovy?

Let's play with Groovy

Some basic differences from Java

Some new operators

Anything in Java but not in Groovy

Expert Groovy

Best practices

What is Groovy?

In 1995, Java changed the world

Now Java bloats with too many frameworks, libs... many organizations have to consider Ruby, LAMP, .NET for more productive and agile at lower costs

Groovy appeared in 2003 promising more complete and dynamic language for JVM instead of Ruby, Python, or JavaScript implementation for JVM.

Let's play with Groovy

Our famous Hello World in Java

Switch Hello World Java to Groovy

Differences from Java

Fewer imports: java.io

java.math

java.net

java.util

groovy.lang

groovy.util

Differences from Java

The truthJava:
if (mySet == null || mySet.isEmpty()) { ...}

Groovy:if (!mySet) { ...}

New Operators

?. (NULL-SAFE OBJECT NAVIGATION)

?: (ELVIS!)

*. (THE SPREAD-DOT OPERATOR)

(COMPARISONS WITH A SPACESHIP)

${} (GROOVY STRINGS)

[] (ARRAY-STYLE NOTATION FOR LISTS AND MAPS)

In Java but not in Groovy

Java FOR loop

No DO...WHILE

Inner and anonymous classes: Not fully supported

Expert Groovy

Closures: single-method anonymous classes[ "apple", "pear", "cherry" ].each { println it }

Duck Typing: Applied to dynamic languages, it means that if an object has a particular property or method signature, then it doesnt matter what type the object is, you can still call that method or access that property. This is only possible in dynamic languages because properties and methods are resolved at runtime.

Best Practices

Use idiomatic Groovy

Experiment

Use methods where appropriate

Use explicit types in method signatures

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