The document provides an overview of Groovy and Java code examples for performing common tasks like printing "Hello World", reading files, making web requests, using strings, importing packages, and using Swing/SwingBuilder for GUIs. It also shows examples of using Groovy with Java libraries for Excel files, Ant, and JSON. Additional sections cover parallel processing with GPars, contract programming with GContracts, method chaining, Grails basics, and Gaelyk controllers and views.

1. G*
JJUG CCC 2011 Spring
@kiy0taka

2. ※ kiy0taka 0

3. G*

4. Groovy?

5. HelloWorld.java
public class HelloWorld {
public static void main(String[] args) {
System.out.println("Hello, World!");
}
}

6. HelloWorld.groovy
public class HelloWorld {
public static void main(String[] args) {
System.out.println("Hello, World!");
}
}
Java

7. HelloWorld.groovy
public class HelloWorld {
public static void main(String[] args) {
System.out.println("Hello, World!")
}
}

8. HelloWorld.groovy
public class HelloWorld {
public static void main(String[] args) {
System.out.println "Hello, World!"
}
}

9. HelloWorld.groovy
public static void main(String[] args) {
System.out.println "Hello, World!"
}

10. HelloWorld.groovy
System.out.println "Hello, World!"
main

11. HelloWorld.groovy
println "Hello, World!"
System.out.println → println

12. One-Liner
groovy -e "println 'Hello, World!'"

14. Java
def file = new File("./hoge.txt")

15. def text = new File("./hoge.txt").text

16. Web
new URL('http://www.java-users.jp/contents/').getText('UTF-8')

17. String
println 'ls -la /opt/local'.execute().text
total 8
drwxr-xr-x 12 root admin 408 11 23 19:32 .
drwxr-xr-x 3 root admin 102 11 7 14:34 ..
drwxr-xr-x 5 root wheel 170 11 24 13:02 Library
drwxr-xr-x 686 root admin 23324 11 27 18:06 bin
drwxr-xr-x 25 root admin 850 11 24 17:01 etc
drwxr-xr-x 177 root admin 6018 11 24 17:01 include
drwxr-xr-x 988 root admin 33592 11 24 17:01 lib
drwxr-xr-x 22 root admin 748 11 24 16:17 libexec
lrwxr-xr-x 1 65534 wheel 9 11 23 18:42 man -> share/man
drwxr-xr-x 5 root admin 170 11 24 13:37 sbin
drwxr-xr-x 76 root admin 2584 11 27 18:06 share
drwxr-xr-x 8 root admin 272 11 24 13:02 var

18. import
import java.lang
import java.math
import java.io
import java.net
import java.util
import groovy.lang
import groovy.util

19. Java
import org.apache.poi.hssf.usermodel.*
def workBook = new HSSFWorkbook(new File('./foo.xls')
workBook.newInputStream()).sheets.each { sheet ->
sheet.firstRowNum.upto(sheet.lastRowNum) {
sheet.getRow(it).with { row ->
row.firstCellNum.upto(row.lastCellNum - 1) {
println row.getCell(it).stringCellValue
}
}
}
}

20. jar
@Grab('org.apache.poi:poi:3.2-FINAL')
import org.apache.poi.hssf.usermodel.*
def workBook = new HSSFWorkbook(new File('./foo.xls')
workBook.newInputStream()).sheets.each { sheet ->
sheet.firstRowNum.upto(sheet.lastRowNum) {
sheet.getRow(it).with { row ->
row.firstCellNum.upto(row.lastCellNum - 1) {
println row.getCell(it).stringCellValue
}
}
}
}

21. Ant
def ant = new AntBuilder()
ant.unzip(src: 'xxx.zip', dest:'dest')
ant.mail(mailhost:'hostname', subject:'hello',
charset:'utf-8',
user:user,
password:password) {
from address:'xxx@example.com'
to address:'kiy0taka333@gmail.com'
message 'Hello World!'
}

24. // Groovy
$ time groovy -e "println 'Hello'"
Hello
real!0m1.292s
user!0m1.283s
sys! 0m0.192s
// GroovyServ
$ time groovyclient -e "println 'Hello'"
Hello
real!0m0.036s
user!0m0.001s
sys! 0m0.003s

26. Swing(Java)
contentPane.add(button);
package sample;
setDefaultCloseOperation(EXIT_ON_CLOSE);
import java.awt.Container; pack();
import java.awt.GridLayout; setVisible(true);
import java.awt.event.ActionEvent; }
import java.awt.event.ActionListener;
public static void main(String[] args) {
import javax.swing.JButton; SwingUtilities.invokeLater(new Runnable() {
import javax.swing.JFrame; public void run() {
import javax.swing.JLabel; new Hello();
import javax.swing.JTextArea; }
import javax.swing.SwingUtilities; });
}
public class Hello extends JFrame { }
public Hello() {
super("Hello");
Container contentPane = getContentPane();
contentPane.setLayout(new GridLayout(3, 1));
JLabel label = new JLabel("Label");
contentPane.add(label);
JTextArea textArea = new JTextArea("Text Area");
textArea.setColumns(20);
textArea.setRows(2);
contentPane.add(textArea);
JButton button = new JButton("Button");
button.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
...
}
});

27. Groovy
import groovy.swing.SwingBuilder
new SwingBuilder().edt {
frame(title:'Hello', show:true, pack:true) {
gridLayout(cols:1, rows:3)
label 'Label'
textArea('Text Area', rows:2, columns:20)
button('Button', actionPerformed:{ evt ->
...
})
}
}

28. SwingBuilder
import groovy.swing.SwingBuilder
new SwingBuilder().edt {
frame(show:true, pack:true) {
tableLayout {
tr {
td { label 'UserName: ' }
td { textField columns:20 }
}
tr {
td { label 'Password: ' }
td { passwordField columns:20 }
}
tr {
td(colspan:2) { button 'Login' }
}
}
}
}

29. https://gist.github.com/913279

31. h2console.groovy
@Grab('org.mortbay.jetty:jetty-embedded:6.1.25')
@Grab('com.h2database:h2:1.2.144')
@Grab('mysql:mysql-connector-java:5.1.13')
import org.mortbay.jetty.Server
import org.mortbay.jetty.servlet.Context
import org.h2.server.web.WebServlet
def server = new Server(8080)
new Context(server, "/", Context.SESSIONS)
.addServlet(WebServlet, "/*")
server.start()
https://gist.github.com/717932

33. please show the
square_root of 100

34. show = { println it }
square_root = { Math.sqrt(it) }
def please(action) {
[the: { what ->
[of: { n -> action(what(n)) }]
}]
}
please(show).the(square_root).of(100)

35. show = { println it }
square_root = { Math.sqrt(it) }
def please(action) {
[the: { what ->
[of: { n -> action(what(n)) }]
}]
}
please show the square_root of 100

36. Object.metaClass. =
Object.metaClass. =
{ clos -> clos(delegate) }
= { it }
= { println it }
= { Math.sqrt(it) }
100

39. import static groovyx.gpars.GParsPool.withPool
def list = [1, 2, 3, 4, 5]
withPool {
def result = list.collectParallel { it * 2 }
assert result == [2, 4, 6, 8, 10]
}

41. import groovy.json.* def slurper = new JsonSlurper()
def json = slurper.parseText(text)
def text = '''[ assert json == [
["aaa", "bbb", "ccc"], ["aaa", "bbb", "ccc"],
{ [
"key1" : "value1", "key1" : "value1",
"key2" : "value2", "key2" : "value2",
"key3" : "value3", "key3" : "value3",
"key4" : "" "key4" : ""
}, ],
["ddd", "eee", "fff"] ["ddd", "eee", "fff"]
] ]
'''

42. import groovy.json.*
def json = new JsonBuilder()
json (
["aaa", "bbb", "ccc"],
[
"key1" : "value1",
"key2" : "value2",
"key3" : "value3",
"key4" : ""
],
["ddd", "eee", "fff"]
)
println json

44. import org.gcontracts.annotations.*
@Invariant({ speed() >= 0 })
class Rocket {
@Requires({ isStarted() })
@Ensures({ old.speed < speed })
def accelerate() { ... }
boolean isStarted() { ... }
def speed() { ... }
}

45. def plus2 = { it + 2 }
def times3 = { it * 3 }
def times3plus2 = plus2 << times3
assert times3plus2(3) == 11
assert times3plus2(4) == plus2(times3(4))
def plus2times3 = times3 << plus2
assert plus2times3(3) == 15
assert plus2times3(5) == times3(plus2(5))
assert times3plus2(3) == (times3 >> plus2)(3)

48. @Log
import groovy.util.logging.*
@Log
class Car {
Car() {
log.info 'Car constructed'
}
}
def c = new Car()
@Commons @Log4j @Slf4j

49. @Log @Commons @Log4j @Slf4j
@Field @PackageScope
@AutoClone @AutoExternalizable
@ThreadInterrupt @TimedInterrupt
@ConditionalInterrupt @ToString
@EqualsAndHashCode @TupleConstructor
@Canonical @InheritConstructors
@WithReadLock @WithWriteLock
@ListenerList

51. Grails

52. create-app generate-all
create-controller generate-controller
create-domain-class generate-views
create-script package
create-service run-app
create-tag-lib run-war
create-unit-test test-app

54. package myapp
class Message {
String text
static constraints = {
text blank:false, maxSize:500
}
}

55. package myapp
class MessageController {
static scaffold = true
}

63. Gaelyk:Controller
log.info "Setting attribute datetime"
request.datetime = new Date().toString()
log.info "Forwarding to the template"
forward '/datetime.gtpl'

64. Gaelyk:View
<% include '/WEB-INF/includes/header.gtpl' %>
<h1>Date / time</h1>
<p>
<% log.info "outputing the datetime attribute" %>
The current date and time:
${request.datetime}
</p>
<% include '/WEB-INF/includes/footer.gtpl' %>

65. Gaelyk:Datastore
import com.google.appengine.api.datastore.Entity
def entity = new Entity("person")
entity.name = "Kiyotaka Oku"
entity.age = 31
entity.save()

66. datastore blobstore
memcache oauth
urlFetch namespace
mail capabilities
images channel
users files
user backends
defaultQueue lifecycle
queues localMode
xmpp app

67. Gaelyk:Datastore
import com.google.appengine.api.datastore.*
import static com.google.appengine.api.datastore.FetchOptions.Builder.*
import static com.google.appengine.api.datastore.Query.FilterOperator.*
import static com.google.appengine.api.datastore.Query.SortDirection.*
def query = new Query('person').with {
addFilter 'age', GREATER_THAN_OR_EQUAL, 30
addSort 'name', ASCENDING
}
def persons = datastore.prepare(query).asList(withLimit(21))

68. Gaelyk:Mail
mail.send sender: "kiy0taka333@gmail.com",
to: "xxx@example.com",
subject: "Hello",
textBody: "Hello, how are you doing?"

69. Gaelyk:TaskQueue
defaultQueue << [
countdownMillis: 1000, url: "/task/dailyEmail",
taskName: "Send daily email newsletter",
method: 'PUT', params: [date: '20090914'],
payload: content
]

71. Griffon

72. Getting Started
$ griffon create-app myapp
$ cd myapp
$ griffon run-app

73. Griffon MVC
MVC

77. Gradle

78. apply plugin: 'groovy'
repositories {
mavenCentral()
}
dependencies {
groovy 'org.codehaus.groovy:groovy:1.8.0'
compile 'junit:junit:4.8.2'
}

79. $ gradle clean build
:clean
:compileJava
:compileGroovy
:processResources
:classes
:jar
:assemble
:compileTestJava
:compileTestGroovy
:processTestResources
:testClasses
:test
:check
:build
BUILD SUCCESSFUL
Total time: 13.766 secs

80. task checksum << {
fileList('../antLoadfileResources').each {File file ->
ant.checksum(file: file, property: "cs_$file.name")
println "$file.name Checksum: ${ant.properties["cs_$file.name"]}"
}
}
task loadfile << {
fileList('../antLoadfileResources').each {File file ->
ant.loadfile(srcFile: file, property: file.name)
println "I'm fond of $file.name"
}
}
File[] fileList(String dir) {
file(dir).listFiles({file -> file.isFile() } as FileFilter).sort()
}

83. G*Magazine

84. G*