Intro to Groovy Gr8Ladies Gr8Workshop December 2014

Slides for the Intro to Groovy at the Gr8Ladies Gr8Workshop December 6, 2014

Transcript

1. INTRO TO GROOVY GR8LADIES GR8WORKSHOP DECEMBER 6, 2014 Presented By / Jenn Strater @jennstrater
2. WHO AM I? Software Engineer Healthcare Communications Division Minneapolis, MN Co-Founder
3. WHO ARE YOU? Students? Professional Developers? Java .NET PHP Groovy?
4. FORMAT Ask questions! Stop me if something doesn't make sense
5. OUTLINE Groovy Overview Basic Data Types Functions Groovy Truth Loops Search Examples OOP APIs* Files*
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:
7. Open source -- maintained by and programmers like you! contribute: Pivotal http://groovy-lang.org https://github.com/groovy/groovy-core
8. THE GROOVY ECOSYSTEM Grails Griffon Gradle and And Many More! Spock Geb Ratpack
9. GRAILS ARCHITECTURE
10. WHEN TO USE GROOVY existing java libraries developers know java or another JVM language quick prototyping scripting writing tests
11. WHEN NOT TO USE GROOVY lots of legacy code in another language especially Ruby need 'bare metal' level performance
12. SCRIPTING Console Shell
13. FOLLOW ALONG http://groovyconsole.appspot.com
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.
15. HELLO,WORLD! println "Hello, World!" ‐> Hello, World!
16. DATA TYPES Strings Collections Lists Maps Ranges Closures Def
17. STRINGS (examples in console) Single Quoted Double Quoted Multi-line
18. COLLECTIONS
19. LISTS (examples in console) definition get/set value append multiply
20. MAPS (examples in console) definition get/set by keys get all keys/values
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]
22. FUNCTIONS int double(x) { x * 2 } Flexible, familiar syntax Optional parenthesis when calling functions parameter typing return statements
23. double(2) ‐‐> 4 double 8 ‐‐> 16
24. CLOSURES Code as Data (to the console!) code as data definition call
25. (examples in console) OBJECT ORIENTED PROGRAMMING
26. GROOVY TRUTH False values Null Zero Empty Set Empty String
27. LOOPS AND SPECIAL FUNCTIONS Basic For Loop Each Collect Spread Dot
28. 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]
29. EACH Map m = [val1: 2, val2: 4, val3: 6] List dl = [] m.each { key, value ‐> dl << value * 2 } println dl ‐‐> [4, 8, 12]
30. COLLECT Map m = [var1: 2, var2: 4, var3: 6] List dl = m.collect { name, value ‐> value * 2 } println dl ‐‐> [4, 8, 12]
31. SPREAD DOT (1..3).multiply(2) ‐‐>[1,2,3,1,2,3] (1..3)*.multiply(2) ‐‐> [2,4,6]
32. 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()
33. 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()
34. 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]
35. 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 + ' ' } }
36. FILE PROCESING
37. CREATING & WRITING TO FILES def myFile = new File('foo.txt') myFile.write 'hello, world!!\n' myFile.append('and hello universe!')
38. READING FILES def myFile = new File('foo.txt') myFile.eachLine { line ‐> def processedLine = line.replaceAll('hello','hi') println processedLine } ‐‐> hi, world! ‐‐> and hi universe!
39. LET'S PUT IT ALL TOGETHER (group coding in console)
40. QUESTIONS? Resources http://groovy-lang.og http:/gr8ladies.org