「CoffeeScript によるデザインパターン(Iterator)」ブログ用

iterator.coffee

class @ArrayIterator
  constructor: (@array) ->
    @index = 0

  hasNext: ->
    @index < @array.length

  item: ->
    @array[@index]

  nextItem: ->
    value = @array[@index]
    @index += 1
    value

@merge = (array1, array2) ->
  merged = []

  iterator1 = new ArrayIterator(array1)
  iterator2 = new ArrayIterator(array2)

  while iterator1.hasNext() and iterator2.hasNext()
    if iterator1.item() < iterator2.item()
      merged.push iterator1.nextItem()
    else
      merged.push iterator2.nextItem()

  while iterator1.hasNext()
    merged.push iterator1.nextItem()

  while iterator2.hasNext()
    merged.push iterator2.nextItem()

  merged

iterator1.coffee

class @ArrayIterator
  constructor: (@array) ->
    @index = 0

  hasNext: ->
    @index < @array.length

  item: ->
    @array[@index]

  nextItem: ->
    value = @array[@index]
    @index += 1
    value

IteratorSpec.scala

package views

import org.specs2.mutable.Specification

import play.api.test.TestServer
import play.api.test.Helpers.{ running, HTMLUNIT }

class IteratorSpec extends Specification {

  private val testPort = 3333

  "Iterator" should {
    "iterate some items" in {
      running(TestServer(testPort), HTMLUNIT) { browser =>

        browser.goTo(s"http://localhost:${testPort}/iterator")
        browser.executeScript("""
          var array = ["red", "green", "blue"];
          var i = new ArrayIterator(array);
          while (i.hasNext()) console.log("item: " + i.nextItem());
        """)
        browser.$("#__console_log").getValue must_== """item: red
item: green
item: blue
"""
        browser.$("#__console_warn").getValue must beNull
      }
    }

    "iterate no item" in {
      running(TestServer(testPort), HTMLUNIT) { browser =>

        browser.goTo(s"http://localhost:${testPort}/iterator")
        browser.executeScript("""
          var array = [];
          var i = new ArrayIterator(array);
          while (i.hasNext()) console.log("item: " + i.nextItem());
        """)
        browser.$("#__console_log").getValue must beNull
        browser.$("#__console_warn").getValue must beNull
      }
    }

    "merge some items" in {
      running(TestServer(testPort), HTMLUNIT) { browser =>

        browser.goTo(s"http://localhost:${testPort}/iterator")
        browser.executeScript("""
          var array1 = [1, 3, 5, 7, 9];
          var array2 = [2, 6, 10, 12];
          console.log(merge(array1, array2));
        """)
        browser.$("#__console_log").getValue must_== """1,2,3,5,6,7,9,10,12
"""
        browser.$("#__console_warn").getValue must beNull
      }
    }

    "merge no item" in {
      running(TestServer(testPort), HTMLUNIT) { browser =>

        browser.goTo(s"http://localhost:${testPort}/iterator")
        browser.executeScript("""
          console.log(merge([], []));
        """)
        browser.$("#__console_log").getValue must_== ""
        browser.$("#__console_warn").getValue must beNull
      }
    }
  }
}