Groovy at Gr8Ladies Iowa Code Camp

Presentation for Iowa Code Camp November 1, 2014

You can also see the slides with audio at: https://www.youtube.com/watch?v=CpR8AOzVo34

Transcript

1. GROOVY AT
   GR8LADIES
   IOWA CODE CAMP 14
   NOVEMBER 1, 2014
   Presented By /
   Jenn Strater @jennstrater
   

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2. WHO AM I?
   Software Engineer
   Healthcare Communications Division
   Minneapolis, MN
   Co-Founder
   

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3. WHO ARE YOU?
   Students?
   Professional Developers?
   Java
   .NET
   PHP
   Groovy?
   

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4. DISCLAIMER
   I may say something wrong!
   

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5. OUTLINE
   Groovy Overview
   Basic Data Types
   Functions
   Loops
   Search
   Examples
   APIs*
   Files*
   

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6. WHAT'S GROOVY
   Dynamic, compiled language for the Java Virtual
   Machine(JVM).
   Interoperable with existing Java libraries
   Concise, easy to read code
   Used by many major companies including:
   

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7. Open source -- maintained by and programmers
   like you!
   contribute:
   Pivotal
   http://groovy-lang.org
   https://github.com/groovy/groovy-core
   

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8. THE GROOVY ECOSYSTEM
   Grails
   Griffon
   Gradle
   and
   And Many More!
   Spock Geb
   Ratpack
   

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9. GROOVY ARCHITECTURE
   

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10. WHEN TO USE GROOVY
    existing java libraries
    developers know java or another JVM language
    quick prototyping
    scripting
    writing tests
    

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11. WHEN NOT TO USE
    GROOVY
    lots of legacy code in another language especially Ruby
    need 'bare metal' level performance
    

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12. SCRIPTING
    Console
    Shell
    

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13. FOLLOW ALONG
    http://groovyconsole.appspot.com
    

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14. THINGS TO REMEMBER!
    1. There is more than one way to do almost anything.
    2. It's probably optional.
    semi-colons
    typing
    parenthesis around parameters
    return statements
    3. By default, the last command executed is what's returned.
    

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15. HELLO,WORLD!
    println "Hello, Iowa Code Camp!"
    -> Hello, Iowa Code Camp!
    

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16. DATA TYPES
    Strings
    Collections
    Lists
    Maps
    Ranges
    Closures
    Def
    

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17. STRINGS
    (examples in console)
    Single Quoted
    Double Quoted
    Multi-line
    

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18. COLLECTIONS
    

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19. LISTS
    (examples in console)
    definition
    get/set value
    append
    multiply
    

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20. MAPS
    (examples in console)
    definition
    get/set by keys
    get all keys/values
    

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21. RANGES
    println (1..10)
    -->[1,2,3,4,5,6,7,8,9,10]
    println (1..<10)
    -->[1,2,3,4,5,6,7,8,9]
    

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22. FUNCTIONS
    int double(x) {
    x * 2
    }
    Flexible, familiar syntax
    Optional
    parenthesis when calling functions
    parameter typing
    return statements
    

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23. double(2)
    --> 4
    double 8
    --> 16
    

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24. CLOSURES
    Code as Data
    (to the console!)
    code as data
    definition
    call
    

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25. LOOPS AND SPECIAL
    FUNCTIONS
    Basic For Loop
    Each
    Collect
    Spread Dot
    

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26. BASIC LOOPS
    List dl = [];
    for(int i=1; i<4; i++){
    dl.add(i * 2);
    }
    println dl;
    --> [2,4,6]
    List dl = []
    for(i in [1,2,3]) {
    dl << i * 2
    }
    println dl
    --> [2,4,6]
    

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27. EACH
    Map m = [val1: 2, val2: 4, val3: 6]
    List dl = []
    m.each { key, value ->
    dl << value * 2
    }
    println dl
    --> [4, 8, 12]
    

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28. COLLECT
    Map m = [var1: 2, var2: 4, var3: 6]
    List dl = m.collect { name, value ->
    value * 2
    }
    println dl
    --> [4, 8, 12]
    

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29. SPREAD DOT
    (1..3).multiply(2)
    -->[1,2,3,1,2,3]
    (1..3)*.multiply(2)
    --> [2,4,6]
    

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30. TRY IT!
    Let's groovy-fy this code
    List l = [-1,2,-3,-17]
    List al = []
    for ( i in l ) {
    al << i.abs()
    }
    println al
    --> [1,2,3,17]
    [-1,2,-3,-17]*.abs()
    

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31. TRY IT!
    Sum the numbers from 1 to 10
    option1:
    int answer = 0
    for (i in [1,2,3,4,5,6,7,8,9,10]) {
    answer += i
    }
    println answer
    option2:
    int answer = 0
    (1..10).each {
    answer = answer + it
    }
    println answer
    Bonus answer:
    (1..10).sum()
    

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32. SEARCH
    Map m = [val1: 2, val2: 4, val3: 6]
    find
    m.find{it.value % 2 == 0 && it.value % 3 != 0}
    --> val1:2
    findAll
    m.findAll{it.value % 2 == 0 && it.value % 3 != 0}
    --> [val1:2,val2:4]
    

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33. APIS
    (in console)
    @Grab(group='org.codehaus.groovy.modules.http-builder',
    module='http-builder', version='0.7.1')
    import groovyx.net.http.RESTClient
    def http = new RESTClient("http://api.icndb.com")
    http.get(path: '/jokes/random/5', query: [exclude: 'explicit']) { resp, reader ->
    reader.value.joke.each{
    println it + '
    '
    }
    }
    

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34. FILE PROCESING
    

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35. CREATING & WRITING TO
    FILES
    def myFile = new File('foo.txt')
    myFile.write 'hello, world!!\n'
    myFile.append('and hello universe!')
    

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36. READING FILES
    def myFile = new File('foo.txt')
    myFile.eachLine { line ->
    def processedLine = line.replaceAll('hello','hi')
    println processedLine
    }
    --> hi, world!
    --> and hi universe!
    

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37. LET'S PUT IT ALL TOGETHER
    (group coding in console)
    

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38. QUESTIONS?
    Resources
    http://groovy-lang.og
    http:/gr8ladies.org
    

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