The document includes various Scala programming examples, demonstrating the language's syntax and features such as case classes, methods, and collection operations. It also covers topics like entity and repository patterns, cloning, and functional programming aspects like higher-order functions and patterns matching. The examples illustrate the creation and manipulation of classes, including user-defined types and their interactions.

1. DDD + Scala
(@j5ik2o)

2. DDD , Scala , DSL , ...
DDD 2 (4,5,6 )
@j5ik2o

3. agenda
Scala DDD
Scala
DDD + Scala
DSL
JavaBeans

4. Scala

5. Scala
Scala
.scala .class
Java

6. Scala vs Java
Money Scala }
public BigDecimal getAmount() {
case class Money(amount :
BigDecimal, currency : Currency) return amount;
Money Java }
public class Money { public Currency getCurrency() {
private final BigDecimal amount; return currency;
}
private final Currency currency;
public Money(BigDecimal amnt, / equals, hashCode
/
Currency creny) { (ry
amount = amt;
}
currency = creny;

7. Hello, World!!
object HelloWorld{
def main(args: Array[String]):Unit = {
println(“Hello, World!!”)
}
}

8. val
scala> val name = "Junichi Kato"
name: java.lang.String = Junichi Kato
scala> name = "JUNICHI KATO"
<console>:6: error: reassignment to val
name = "JUNICHI KATO"

9. var
scala> var name = "Junichi Kato"
name: java.lang.String = Junichi Kato
scala> name = "JUNICHI KATO"
name: java.lang.String = JUNICHI KATO

10. type
scala> val name = "Junichi Kato"
name: java.lang.String = Junichi Kato
scala> val name:String = "Junichi Kato"
name: String = Junichi Kato
scala> val num:Number = 100L
num: java.lang.Number = 100

11. method
def add(a:Int, b:Int):Int = {
return a + b
}
def add(a:Int, b:Int):Int = a + b
def add(a:Int, b:Int) = a + b
hoge.add(1, 2) / 3
/

12. if & for
if
val a = 10
val ret = if (a % 2 == 0) true else false
val ret = if (a % 2 == 0) { println(“ ”); true }
else { println(“ ”); false }
def isEven(n: Int) = if (n % 2 == 0) true else false
for
for(i <- 1 to 3) println(i) / 1,2,3
/
for(i <- Array(1,2,3)) println(i) / 1,2,3
/
val numbers = for(i <- 1 to 10) yield i

13. class
class PersonName
(fn: String, ln: String){
require(fn.length > 0) // IAE
require(ln.length > 0) // IAE
val firstName = fn
val lastName = ln
def fullName = “%s, %s”.format(firstName, lastName)
}

14. class
class PersonName(val firstName:String, val
lastName: String){
require(firstName.length > 0)
require(lastName.length > 0)
def fullName = “%s, %s”.format(firstName,
lastName)

15. class
val pn = new PersonName(“Junichi”, “Kato”)
println(pn.fullName)
val pn2 = new PersonName(“”, “Kato”) / IAE
/

16. object
object EmployeeDao {
val DEFAULT_NAME = ...
def findAll = ...
}
val result = EmployeeDao.findAll
val defaultName = EmployeeDao.DEFAULT_NAME

17. { , }
class Money(val amount:BigDecimal, val currency: Currency) ...
object Money {
val JPY = Currency.getInstance(“JPY”)
def apply(amount: BigDecimal, currency: Currency) = new
Money(amount, currency)
}
val money:Money = Money(100, Money. JPY)
/ val money:Money = Money.apply(100, Money.JPY)
/

18. match
def numberMatch(n:Int) = n match {
case 1 => “one”
case 2 | 3 => “t wo or three”
case _ => “other”
}
println(numberMatch(1)) / one
/
println(numberMatch(2)) / t wo or three
/
println(numberMatch(3)) / t wo or three
/
println(numberMatch(4)) / other
/

19. match
val pattern = """([a-z]+)""".r case Array(1,2,3) => println(“
def matchTest(word: Any) = word 1,2,3 ”)
match {
case _ => throw new
case “ABC” => println(“ABC ”) IllegalArgumentException
case pattern(s) => println(" }
= "+s) matchTest(“ABC”) / ABC
/
case s: String => println(“ matchTest("aaaa") // =
= (%s)”.format(s)) (aaaa)
case n: Int if (n >= 2) => println(“2 matchTest(10) / 2
/
”)
matchTest(Array(1,2,3)) //
1,2,3

20. (a:Int) => a * a
val square: (Int) => Int = (a:Int) => a * a
val square = (a:Int) => a * a
val result = square(2) / 4
/

21. object MyMath {
def add(a:Int, b:Int) = a + b
}
val f1 = MyMath.add _
val f2: (Int,Int) => Int = MyMath.add

22. Collection
val il1 = List(1,2,3)
val il2 = list :+ 4 / 1,2,3,4
/
val im1 = Map(1 -> “ 2 -> “b”, 3 -> “c”)
a”,
val im2 = m1 + (4 -> “d”) / 1 -> “ 2 -> “b”, 3 -> “c”, 4 -> “d”
/ a”,
val ml = ListBuffer(1,2,3)
ml += 4
val mm = collection.mutalble.Map(1 -> “ 2 -> “b”, 3 -> “c”)
a”,
mm += (4 -> “d”)

23. Collection
val numbers = List(1,2,3,45)
numbers.foreach((n:Int) => println(n) ) / (1)
/
numbers.foreach(n => println(n)) / (2)
/
numbers.foreach(_ => println(_)) / (3)
/
numbers.foreach(println(_)) / (4)
/
numbers.foreach(println) / (5)
/
varl map = Map(1 -> “ 2 -> “b”)
a”,
map.foreach(entry => println(“key = %s, value =
%s”.format(entry._1,entry._2)))

24. Collection
val evens = numbers.filter(_ % 2 == 0) //
numbers
val list = List(1,2,3).map(_ * 2) / 2,4,6
/

25. Collection
Range ( (Seq) )
val range = 1 to 10; range.foreach(println)
for(i <- 1 to 10 by 2) println(i) / 1 3 5 7 9
/
6 FizzBuzz
(1 to 100).map{
case n if (n % 15 == 0) => “FizzBuzz”
case n if (n % 3 == 0) => “Fizz”
case n if (n % 5 == 0) => “Buzz”
case n => n
}.foreach(println)

26. trait
trait Greeting { def greet:Unit }
class JapaneseGreeting extends Greeting {
def greet = println(“ ”)
}
class EnglishGreeting extends Greeting {
def greet = println(“Hello”)
}
mix-in
trait Logging { def log(msg: String) = println(msg) }
class Employee(name:String) extends AbstractEmployee with
Logging {
log(“name = “+name)
}

27. DDD + Scala

28. Domain Object &
Lifecycle

29. Entity
trait Entity {
val id: String // OK
def equals(other: Any) = other match {
case that: Entity => id == that.id
case _ => false
}
def hashCode = id.hashCode
}

30. Entity
class Employee(val id: String, val name:
String)extends Entity
val kato1 = new Employee(“1”, “Junichi Kato”)
val kato2 = new Employee(“2”, “Junichi Kato”)
val kato3 = new Employee(“3”, “JUNICHI KATO”)
assert(kato1 != kato2)
assert(kato1 == kato3)

31. Entity with Factory
class Employee object Employee{
(val id:String, def apply(id:String,
name:String,
var name:String, dept:Department) = new
var dept:Department) Employee(id, name, dept)
extends Entity }

32. Entity with Factory
val kato = Employee(“KATO”,
Department(“DEV”))

33. Value Object with Factory
class Money override def toString =
"Money(%s, %s)".format(amount,
(val amount: BigDecimal, currency)
val currency: Currency){ }
override def equals(that: Any): object Money {
Boolean = that match {
def apply(amount: BigDecimal,
case other: Money => amount == currency: Currency) = new
other.amount && currency == Money(amount, currency)
other.currency
def unapply(money: Money) =
case _ => false Some(money.amount,
} money.currency)
override def hashCode = }
amount.hashCode +
currency.hashCode

34. Value Object with Factory
VO
assert(Money(100, Money.JPY) == Money(100, Money.JPY))
assert(Money(100, Money.JPY) != Money(105, Money.JPY))
assert(Money(100, Money.JPY) != Money(100, Money.USD))
unapply
val Money(amt, cry) = money1_100yen
println(“
amount = %s, currency = %s”.format(amt, cry))
money1_100yen match { / match
/
case Money(amt, cry) => println(“
amount = %s, currency = %s”.format(amt,
cry))
case _ => ()
}

35. Value Object(case class)
case class Money(amount: BigDecimal, currency:
Currency)
apply, unapply
val
toString, equals, hashCode
VO case class Money(amount:
BigDecimal, currency: Currency) extends ValueObject

36. ValueObject Builder
case class PersonName(firstName: String, lastName:
String)
class PersonNameBuilder extends
ValueObjectBuidler[PersonName, PersonNameBuilder] { ... }
VO
val personName1 = new
PersonNameBuilder().withFirstName("Junichi").withLastNa
me("Kato").build
val personName2 = new
PersonNameBuilder().withLastName(lastName.toUpperCase
).build(personName1)

37. Service
object TransferSer vice {
def transfer(money: Money,
from:BankAccount, to:BankAccount) =
to.push(from.pull(money))
}
TransferService.transfer(Money(1000,JPY),
BankAccount(“012345”),
BankAccount(“543210”))

38. Aggregate
class Employee(val id:String, var name:String, var dept:
Department) extends Entity
Employee id, name, dept

39. Aggregate
Department ( )
class Employee(val id:String, var name:String, var dept:
Department) extends Entity
class Department(val id: String, var name: String) extends Entity
val dept = Department(“1:1”, “DEV)
val emp = Employee(“1”, “KATO”, dept) / (1)
/
dept.name = “SALES” / (1)
/
val dept = emp.dept / (2)
/
dept.name = “SALES” / (2)
/

40. Aggregate(Cloneable)
@cloneable }
class Department(val id: String, var name: override def clone = { / (4)
/
String) extends Entity {
val result =
override def clone = super.clone.asInstanceOf[Employee]
super.clone.asInstanceOf[Department]
result.dpt = dpt.clone
}
}
@cloneable
}
class Employee(val id:String, var
val dept = Department(“1:1”, “DEV”)
name:String, _dpt: Department) extends
Entity { val emp = Employee(“1”, “KATO”, dept) / (1)
/
private var dpt = _dpt.clone / (1)
/ dept.name = “SALES”
def dept = dpt.clone / getDept
/ (2) val dept = emp.dept / (2)
/
def dept_= (value: Deaprtment) { // dept.name = “SALES”
setDept emp.dept = Department(“1:1”, “SALES”) / (3)
/
dpt = value.clone / (3)
/ val cloneEmp = emp.clone / (4)
/

41. Aggregate(clone)
clone Mix-in
@cloneable
trait EntityCloneable[T <: Entity] {
this: Entity =>
override def clone: T =
super.clone.asInstanceOf[T]
}

42. Aggregate(clone)
class Employee
(val id: String,
var name: String)
extends Entity with
EntityCloneable[Employee]
val emp = Employee(“1”, “Kato”)
val cloneEmp = emp.clone

43. Aggregate(Factory)
Factory
object Department {
def apply(dept: Department) =
new Department(dept, dept.name)
}
object Employee {
def apply(emp: Employee) =
new Employee(emp.id, emp.name, Department(emp.dept))
}
val emp = Employee(“1”, “KATO”, Department(“1:1”, “DEV”))
val cloneEmp = Employee(emp)

44. Repository
trait EntityResolver[T <: Entity] extends Iterable[T]
{
def resolve(id: String): T
def apply(id: String) = resolve(id)
def contains(id: String): Boolean = exists(_.id == id)
def contains(entity: T): Boolean = exists(_ == entity)
}

45. Repository
class EmployeeResolver extends val er = new EmployeeResolver
EntityResolver[Employee] {
val employee = er.resolve(id)
private val employees =
val employee = er(id) / er.apply
/
Map(“1” -> Employee(“1”,
-> resolve
“KATO”, Department(“1:1”,
“DEV”))) val employee = er.contains(id)
def resolve(id: String) = val exists = er.exists(_.name ==
employees(id) “KATO”)
def iterator = val employees =
employees.map(e => er.filter(_.name.startWith(“K”))
e._2.clone).iterator
er.foreach(println)
}

46. Repository
trait Repository[T <: Entity] extends
EntityResolver[T] {
def store(entity: T)
def update(identifier: Identifier, entity:T) =
store(entity)
def delete(identity: Identifier)
def delete(entity: T)
}

47. Repository
class EmployeeRepository / resolve, iterator ...
/
extends
Repository[Employee] { }
private val employees = val er = new
collection.mutalble.Map.emp EmployeeRepository
ty[String, Employee] val emp = Employee(id,
def store(emp: Employee) = “KATO”, Department(“DEV))
employees += (emp.id -> emp) er.store(emp)
def delete(id: String) = er(id) = emp
employee -= emp.id
er.delete(id)
def delete(emp: Employee) =
delete(emp.id) er.delete(emp)

49. ( )=
id(4a74c322-08ab-450b-b674-793e1d7f399a) = class
Department {
package = dept
fields {
name = java.lang.String
}
}

50. package dept;
public class Department {
private java.lang.String name;
public void setName(java.lang.String name){
this.name = name;
}
public java.lang.String getName(){
return name;
}
}

51. (.ftl)
<#if classMeta.getPackageName()??> <#assign getter = "is"/>
package ${classMeta.getPackageName()}; <#elseif f.getTypeName() ==
"java.lang.Boolean">
</#if>
<#assign getter = "is"/>
public class ${classMeta.getName()} {
<#else>
<#list classMeta.getFieldMetas() as f>
<#assign getter = "get"/>
private ${f.getTypeName()} $
{f.getName()}; </#if>
public void set${f.getName()?cap_first} public ${f.getTypeName()} ${getter}$
(${f.getTypeName()} ${f.getName()}){ {f.getName()?cap_first}(){
this.${f.getName()} = $ return ${f.getName()};
{f.getName()};
}
}
</#list>
}
<#if f.getTypeName() == "boolean">

52. codegen -h
codegen -c sample.config -t template -e export
codegen -c [4a74c322-08ab-450b-
b674-793e1d7f399a]@sample.config -t
template -e export

53. ClassMeta
FieldMeta
CodeGenSer vice
Factory
ClassMetaRepository

54. ClassMeta Entity
package codegen.domain
class ClassMeta
(@BeanProperty val identifier: Identifier, @BeanProperty val name:
String,
val packageName: Option[String], val fieldMetas: List[FieldMeta])
extends Entity {
override def toString: String = "ClassMeta(%s, %s, %s,
%s)".format(identifier, name, packageName, fieldMetas)
def getPackageName(): String = if (packageName.isEmpty) null else
packageName.get
def getFieldMetas(): java.util.List[FieldMeta] = fieldMetas.asJava
}

55. ClassMeta Object
object ClassMeta {
def apply(identifier: Identifier, name: String, packageName: Option[String],
fieldMetas: List[FieldMeta]) =
new ClassMeta(identifier, name, packageName, fieldMetas)
def apply(name: String, packageName: Option[String], fieldMetas:
List[FieldMeta]): ClassMeta =
apply(Identifier(), name, packageName, fieldMetas)
def apply(classMeta: ClassMeta): ClassMeta =
apply(classMeta.identifier, classMeta.name, classMeta.packageName,
classMeta.fieldMetas)
def unapply(classMeta: ClassMeta) =
Some(classMeta.identifier, classMeta.name, classMeta.packageName,
classMeta.fieldMetas)
}

56. FieldMeta VO & VO Factory
case class FieldMeta(@BeanProperty name:
String, @BeanProperty typeName: String)

57. ClassMetaRepository
package codegen.domain
class ClassMetaRepository(configSource: BufferedSource)
extends EntityResolver[ClassMeta] {
private val classMetas = new
ModelParser().parse(configSource)
private val classMetaMap = classMetas.map(classMeta =>
(classMeta.identifier, classMeta)).toMap
def iterator: Iterator[ClassMeta] =
classMetaMap.map(classMeta => ClassMeta(_._2)).iterator
def resolve(identifier: Identifier): ClassMeta =
ClassMeta(classMetaMap(identifier))
}

58. CodeGenSer vice
package codegen.domain val exportClassDir =
getExportClassDir(classMeta)
object CodeGenSer vice{
exportClassDir.mkdirs
def generate(exportDir: File, templateDir: File,
classMetas: List[ClassMeta], using(new FileWriter(new
File(exportClassDir, classMeta.name + ".java"))) {
beginHandler: Option[(ClassMeta) => Unit],
fileWriter =>
endHandler: Option[(ClassMeta) => Unit] ) = {
template.process(rootMap.asJava,
val configuration = new Configuration fileWriter);
fileWriter.flush();
configuration.setDirectoryForTemplateLoading(te
mplateDir) } / using
/
val template = / ...
/
configuration.getTemplate("java.ftl")
} / foreach
/
classMetas.foreach {
}
classMeta =>
/ ...
/
/ ...
/
}
val rootMap = Map("classMeta" ->
classMeta)

59. Application
package codegen.application getExportDir(parameters),
object Application extends Logging { getIdList(parameters))
def main(args: Array[String]) { }
try {
val commandLine = new } catch {
CommandLineParser().parse(args.mkSt
ring(" ")) case e:
CommandLineParseException =>
commandLine match { println("
case Help() => println("""-c ")
[[id1,id2]@]file.config [-t templateDir]
[-e exportDir]""") }
case parameters: Parameters => }
generate(getConfigFile(parameters),
getTemplateDir(parameters), }

60. Application
private def generate(configFile: File, CodeGenSer vice.generate(exportDir, templateDir,
targets,
templateDir: File,
Some({
exportDir: File,
c => info("id(%s) : class %s
ids: List[String]) {
".format(c.identifier.value, c.name))
info("
= %s, = %s, }),
= %s".format(configFile, templateDir, Some({
exportDir)) c => info("id(%s) : class %s
val repos = new ".format(c.identifier.value, c.name))
ClassMetaRepository(Source.fromFile(configFile))
}))
val targets = ids match {
info(" ")
case Nil => repos.toList
case xs => xs.map { } catch {
e => repos.resolve(Identifier(e)) case e: Exception => error("
} ", e)
} }
try { }