Scala之Object的具体使用(小结)

type Throwable = java.lang.Throwable
type Exception = java.lang.Exception
type Error = java.lang.Error
type Seq[+A] = scala.collection.Seq[A]
val Seq = scala.collection.Seq

val siblings = List(Person("Kim"), Person("Julia"), Person("Kenny"))

val recognizer = cm.lookup("recognizer").asInstanceOf[Recognizer]

Recognizer recognizer = (Recognizer)cm.lookup("recognizer");

// open/read the application context file
val ctx = new ClassPathXmlApplicationContext("applicationContext.xml")
// instantiate our dog and cat objects from the application context
val dog = ctx.getBean("dog").asInstanceOf[Animal]
val cat = ctx.getBean("cat").asInstanceOf[Animal]

val objects = Array("a", 1)
val arrayOfObject = objects.asInstanceOf[Array[Object]]
AJavaClass.sendObjects(arrayOfObject)

val info = new DataLine.Info(classOf[TargetDataLine], null)

info = new DataLine.Info(TargetDataLine.class, null);

def printAll(numbers: Int*) {
  println("class: " + numbers.getClass)
}

object Hello extends App {
  println("Hello, world")
}

object Hello2 {
  def main(args: Array[String]) {
    println("Hello, world")
  }
}  

object Hello2 {
  def main(args: Array[String]) {
    println("Hello, world")
  }
}  

object Main extends App {
  CashRegister.open
  CashRegister.close
}

import java.util.Calendar
import java.text.SimpleDateFormat

object DateUtils {
  // as "Thursday, November 29"
  def getCurrentDate: String = getCurrentDateTime("EEEE, MMMM d")
  
  // as "6:20 p.m."
  def getCurrentTime: String = getCurrentDateTime("K:m aa")
  
  // a common function used by other date/time functions
  private def getCurrentDateTime(dateTimeFormat: String): String = {
    val dateFormat = new SimpleDateFormat(dateTimeFormat)
    val cal = Calendar.getInstance()
    dateFormat.format(cal.getTime())
  }
}

DateUtils.getCurrentDate
DateUtils.getCurrentTime

case object StartMessage
case object StopMessage

inputValve ! StopMessage
outputValve ! StopMessage

// Pizza class
class Pizza (var crustType: String) {
  override def toString = "Crust type is " + crustType
}

// companion object
object Pizza {
  val CRUST_TYPE_THIN = "thin"
  val CRUST_TYPE_THICK = "thick"
  def getFoo = "Foo"
}

println(Pizza.CRUST_TYPE_THIN)
println(Pizza.getFoo)

var p = new Pizza(Pizza.CRUST_TYPE_THICK)
println(p)

class Foo {
  private val secret = 2
}

object Foo {
  // access the private class field 'secret'
  def double(foo: Foo) = foo.secret * 2
}

object Driver extends App {
  val f = new Foo
  println(Foo.double(f)) // prints 4
}

class Foo {
  // access the private object field 'obj'
  def printObj { println(s"I can see ${Foo.obj}") }
}

object Foo {
  private val obj = "Foo's object"
}

object Driver extends App {
  val f = new Foo
  f.printObj
}

package com.hust.grid.leesf

package object model {

package com.hust.grid.leesf

package object model {
  // field
  val MAGIC_NUM = 42

  // method
  def echo(a: Any) { println(a) }
  
  // enumeration
  object Margin extends Enumeration {
    type Margin = Value
    val TOP, BOTTOM, LEFT, RIGHT = Value
  }
  
  // type definition
  type MutableMap[K, V] = scala.collection.mutable.Map[K, V]
  
  val MutableMap = scala.collection.mutable.Map
}

package com.hust.grid.leesf.model

object MainDriver extends App {
  // access our method, constant, and enumeration
  echo("Hello, world")
  echo(MAGIC_NUM)
  echo(Margin.LEFT)
  // use our MutableMap type (scala.collection.mutable.Map)
  val mm = MutableMap("name" -> "Al")
  mm += ("password" -> "123")
  for ((k,v) <- mm) printf("key: %s, value: %s\n", k, v)
}

package com.hust.grid.leesf

package object model {

package com.hust.grid.leesf

package object model {

val a = Array(Person("John"), Person("Paul"))

class Person {
  var name: String = _
}

object Person {
  def apply(name: String): Person = {
    var p = new Person
    p.name = name
    p
  }
}

val dawn = Person("Dawn")
val a = Array(Person("Dan"), Person("Elijah"))

case class Person (var name: String)

val p = Person("Fred Flinstone")

val p = Person("Fred Flinstone")

val p = Person.apply("Fred Flinstone")

class Person {
  var name = ""
  var age = 0
}

object Person {
  // a one-arg constructor
  def apply(name: String): Person = {
    var p = new Person
    p.name = name
    p
  }

  // a two-arg constructor
  def apply(name: String, age: Int): Person = {
    var p = new Person
    p.name = name
    p.age = age
    p
  }
}

val fred = Person("Fred")
val john = Person("John", 42)

public Person apply(java.lang.String);

case class Person (var name: String)

// want accessor and mutator methods for the name and age fields
case class Person (var name: String, var age: Int)

// define two auxiliary constructors
object Person {
  def apply() = new Person("<no name>", 0)
  def apply(name: String) = new Person(name, 0)
}

object Test extends App {
  val a = Person()
  val b = Person("Al")
  val c = Person("William Shatner", 82)
  println(a)
  println(b)
  println(c)
  // test the mutator methods
  a.name = "Leonard Nimoy"
  a.age = 82
  println(a)
}

Person(<no name>,0)
Person(Al,0)
Person(William Shatner,82)
Person(Leonard Nimoy,82)

val cat = Animal("cat") // creates a Cat
val dog = Animal("dog") // creates a Dog

trait Animal {
  def speak
}

object Animal {
  private class Dog extends Animal {
    override def speak { println("woof") }
  }
  
  private class Cat extends Animal {
    override def speak { println("meow") }
  }
  
  // the factory method
  
  def apply(s: String): Animal = {
    if (s == "dog") new Dog
    else new Cat
  }
}

val cat = Animal("cat") // creates a Cat
val dog = Animal("dog") // creates a Dog

// an alternative factory method (use one or the other)
def getAnimal(s: String): Animal = {
  if (s == "dog") return new Dog
  else return new Cat
}

val cat = Animal.getAnimal("cat") // returns a Cat
val dog = Animal.getAnimal("dog") // returns a Dog