futures

1 files changed, 99 insertions, 3 deletions

diff --git a/examples/demos/src/main/scala/advanced/Futures.scala b/examples/demos/src/main/scala/advanced/Futures.scala
index 4035fac..6602c61 100644
--- a/examples/demos/src/main/scala/advanced/Futures.scala
+++ b/examples/demos/src/main/scala/advanced/Futures.scala
@@ -1,13 +1,109 @@
 package advanced
 
 import org.scalajs.dom
-
+import org.scalajs.dom.XMLHttpRequest
+import org.scalajs.dom.extensions.{Ajax, KeyCode}
+import scala.collection.mutable
+import scala.concurrent.Future
+import scala.scalajs.js
+import scalatags.JsDom.all._
 import scala.scalajs.js.annotation.JSExport
-
+import scala.scalajs.concurrent.JSExecutionContext.Implicits.runNow
 @JSExport
 object Futures {
+  def main(container: dom.HTMLDivElement,
+            handle: (Seq[String], dom.HTMLDivElement) => Unit) = {
+    val myInput = input(value:="London,Singapore,Berlin,New York").render
+    val output = div.render
+    myInput.onkeyup = (e: dom.KeyboardEvent) => {
+      if (e.keyCode == KeyCode.enter){
+        handle(myInput.value.split(','), output)
+      }
+    }
+    container.appendChild(
+      div(
+        height:="200px",
+        overflow:="scroll",
+        i("Press Enter in the box to fetch temperatures "),
+        myInput,
+        output
+      ).render
+    )
+  }
+  def urlFor(name: String) = {
+    "http://api.openweathermap.org/data/" +
+    "2.5/find?mode=json&q=" +
+    name
+  }
+  def parseTemp(text: String) = {
+    val data = js.JSON.parse(text)
+    val kelvins = data.list
+                      .pop()
+                      .main
+                      .temp
+                      .asInstanceOf[Double]
+    kelvins - 272.15
+  }
+  def formatResults(output: dom.HTMLElement, results: Seq[(String, Double)]) = {
+    output.innerHTML = ""
+    output.appendChild(ul(
+      for((name, temp) <- results) yield li(
+        b(name), " - ", temp.toInt, "C"
+      )
+    ).render)
+  }
   @JSExport
-  def main(container: dom.HTMLDivElement) = {
+  def main0(container: dom.HTMLDivElement) = {
+    def handle0(names: Seq[String], output: dom.HTMLDivElement) = {
+      val results = mutable.Buffer.empty[(String, Double)]
+      for(name <- names){
+        val xhr = new XMLHttpRequest
+        xhr.open("GET", urlFor(name))
+        xhr.onload = (e: dom.Event) => {
+          val temp = parseTemp(xhr.responseText)
+          results.append((name, temp))
+          if (results.length == names.length){
+            formatResults(output, results)
+          }
+        }
+        xhr.send()
+      }
+    }
+    main(container, handle0)
+  }
+  @JSExport
+  def main1(container: dom.HTMLDivElement) = {
+    def handle1(names: Seq[String], output: dom.HTMLDivElement) = {
+      val results = mutable.Buffer.empty[(String, Double)]
+      for{
+        name <- names
+        xhr <- Ajax.get(urlFor(name))
+      } {
+        val temp = parseTemp(xhr.responseText)
+        results.append((name, temp))
+        if (results.length == names.length){
+          formatResults(output, results)
+        }
+      }
+    }
+    main(container, handle1)
+  }
+  @JSExport
+  def main2(container: dom.HTMLDivElement) = {
+    def handle2(names: Seq[String], output: dom.HTMLDivElement) = {
+      val futures = for(name <- names) yield{
+        Ajax.get(urlFor(name)).map( xhr =>
+          (name, parseTemp(xhr.responseText))
+        )
+      }
 
+      for(results <- Future.sequence(futures)){
+        formatResults(output, results)
+      }
+    }
+
+    main(container, handle2)
   }
+
+
 }