Using Groovy is easy and fun. After getting your hands dirty with a few basics it is good to go deeper. In this session we will cover Design Patterns in Groovy, compilation configuration, mixing Java and Groovy, and calling other languages from Groovy. We will show you how to call Scala and Clojure from Groovy. So get ready to take it to the next level.

1. SPRINGONE2GX
WASHINGTON, DC
Unless otherwise indicated, these slides are © 2013 -2015 Pivotal Software, Inc. and licensed under a Creative Commons Attributio n-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
Becoming an Advanced Groovy
Developer
By Tom Henricksen
@tomhenricksen

2. Unless otherwise indicated, these slides are © 2013 -2015 Pivotal Software, Inc. and licensed under a
Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
Agenda
• Design Patterns
• Mixing Java and Groovy
• Calling other languages
2

3. Unless otherwise indicated, these slides are © 2013 -2015 Pivotal Software, Inc. and licensed under a
Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
Groovy Design Patterns
What are Design Patterns?
Types
• Structural
• Creational
• Behavioral
3

4. Unless otherwise indicated, these slides are © 2013 -2015 Pivotal Software, Inc. and licensed under a
Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
Groovy Design Patterns
• Why Design Patterns?
• Good Communication tools
• Don’t force in
4

5. Unless otherwise indicated, these slides are © 2013 -2015 Pivotal Software, Inc. and licensed under a
Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
Groovy Design Patterns
Iterator pattern
• Behavioral
• Traverse collections
5

6. Unless otherwise indicated, these slides are © 2013 -2015 Pivotal Software, Inc. and licensed under a
Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
Groovy Iterator Pattern
6
// Iterator example – for in
for (item in container) { println item }
// Iterator example – eachWithIndex
colors.eachWithIndex{ item, pos ->
printlin “Position $pos contains ‘$item’”
}
// Iterator example – each
(1..3).each {
println “Number ${it}”

7. Unless otherwise indicated, these slides are © 2013 -2015 Pivotal Software, Inc. and licensed under a
Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
Groovy Design Patterns
Adapter Pattern
• Structural
• Wrap functionality
7

8. Unless otherwise indicated, these slides are © 2013 -2015 Pivotal Software, Inc. and licensed under a
Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
Groovy Adaptor Pattern
8
// Adapter example
class SquarePegAdapter {
def peg
def getRadius() {
Math.sqrt(((peg.width / 2) * * 2) * 2)
}
String toString() {
“SquarePegAdapter with peg $peg.width and radius $radius”
}
}

9. Unless otherwise indicated, these slides are © 2013 -2015 Pivotal Software, Inc. and licensed under a
Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
Groovy Design Patterns
Decorator Pattern
• Structural
• Add behavior
9

10. Unless otherwise indicated, these slides are © 2013 -2015 Pivotal Software, Inc. and licensed under a
Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
Groovy Decorator Pattern
10
// Decorator example
class UpperLogger extends Logger {
private Logger logger
UpperLogger(logger) {
this.logger = logger
}
def log(String message) {
logger.log(message.toUpperCase())
}
}

11. Unless otherwise indicated, these slides are © 2013 -2015 Pivotal Software, Inc. and licensed under a
Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
Groovy Design Patterns
Singleton Pattern
• Creational
• Ensure only one
11

12. Unless otherwise indicated, these slides are © 2013 -2015 Pivotal Software, Inc. and licensed under a
Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
Groovy Singleton Pattern
12
// Decorator example
class VoteCollector {
def votes = 0
private static final INSTANCE = new VoteCollector()
static getInstance() { return INSTANCE }
private VoteCollector() { }
def display() { println "Collector:${hashCode()}, Votes:$votes" }
}

13. Unless otherwise indicated, these slides are © 2013 -2015 Pivotal Software, Inc. and licensed under a
Creative Commons Attribution-NonCommercial license: http://creativecommons.org/licenses/by-nc/3.0/
Groovy Design Patterns
Questions
• What design pattern would you add?
13