themillhousegroup · May 21, 2018 20:55 · Mar 20, 2014 · Mar 20, 2014
diff --git a/DirectoryFileCreationWatcher b/DirectoryFileCreationWatcher
@@ -1,4 +1,3 @@
-
 class DirectoryFileCreationWatcher(directoryToWatch:Path) {
   import java.nio.file._
   import java.nio.file.StandardWatchEventKinds._
@@ -84,7 +83,7 @@ class DirectoryFileCreationWatcherSpec extends Specification {
 
     "not notify the caller until the dir contains a matching file - exact match on file" in {
       val future = new DirectoryFileCreationWatcher(watchedDir).awaitFile{ path =>
-        path.toFile.getAbsolutePath.endsWith(testFileName)
+        path.endsWith(testFileName)
       }
 
       future.isCompleted must beFalse

diff --git a/DirectoryFileCreationWatcher b/DirectoryFileCreationWatcher
@@ -0,0 +1,104 @@
+
+class DirectoryFileCreationWatcher(directoryToWatch:Path) {
+  import java.nio.file._
+  import java.nio.file.StandardWatchEventKinds._
+  import scala.concurrent.ExecutionContext.Implicits.global
+  import scala.collection.JavaConversions._
+
+  val watcher = FileSystems.getDefault.newWatchService
+
+  // Work properly on Mac:
+  //http://stackoverflow.com/questions/9588737/is-java-7-watchservice-slow-for-anyone-else
+  val kinds:Array[Kind[_]] = Seq(StandardWatchEventKinds.ENTRY_CREATE).toArray
+  directoryToWatch.register(watcher, kinds, SensitivityWatchEventModifier.HIGH.asInstanceOf[WatchEvent.Modifier])
+
+  /**
+   *
+   * @param pathMatcher a function that returns true if this is the file we're looking for
+   * @return a Future holding a Path that represents the directory in its "new" state
+   */
+  def awaitFile( pathMatcher: Path => Boolean):Future[Path] = Future[Path] {
+    var foundMatch = false
+    while (!foundMatch) {
+      val watchKey = watcher.take // Blocks
+      val events = watchKey.pollEvents
+      foundMatch = events.exists { event =>
+        val wep = event.asInstanceOf[WatchEvent[Path]]
+        pathMatcher(wep.context)
+      }
+      watchKey.reset
+    }
+    directoryToWatch
+  }
+}
+
+class DirectoryFileCreationWatcherSpec extends Specification {
+  import java.nio.file._
+  import scala.concurrent.ExecutionContext.Implicits.global
+  import scala.collection.JavaConversions._
+
+  isolated
+  "DirectoryFileCreationWatcher" should {
+    val watchedDir = Files.createTempDirectory("watchedDir")
+    val testFileName = "testFile.txt"
+    val secondTestFileName = "testFile2.txt"
+    val waitToNoticeChange = 2000
+    val noticeDelay = scala.concurrent.duration.FiniteDuration(waitToNoticeChange, "millis")
+    val halfSecond = scala.concurrent.duration.FiniteDuration(500, "millis")
+
+    def addFileToWatchedDir(fileName:String):java.io.File = {
+      val f = new java.io.File(watchedDir.toFile, fileName)
+      f.createNewFile
+      println(s"added file ${f.getAbsolutePath}")
+      f
+    }
+
+    "not notify the caller until the dir contains a matching file - any file" in {
+      val future = new DirectoryFileCreationWatcher(watchedDir).awaitFile{ path =>
+        true
+      }
+
+      future.isCompleted must beFalse
+
+      addFileToWatchedDir(testFileName)
+
+      Thread.sleep(waitToNoticeChange)
+      future.isCompleted must beTrue
+    }
+
+    "notify the caller with the new contents of the dir - for any file" in {
+      val future = new DirectoryFileCreationWatcher(watchedDir).awaitFile{ path =>
+        true
+      }
+
+      watchedDir.toFile.list.contains(testFileName) must beFalse
+
+      addFileToWatchedDir(testFileName)
+
+      future.map { dirPath =>
+        println(s"dirPath: ${dirPath.toFile.list.mkString}" )
+        dirPath.toFile.list.contains(testFileName)
+      } must beTrue.await(timeout = halfSecond, retries=4)
+    }
+
+
+    "not notify the caller until the dir contains a matching file - exact match on file" in {
+      val future = new DirectoryFileCreationWatcher(watchedDir).awaitFile{ path =>
+        path.toFile.getAbsolutePath.endsWith(testFileName)
+      }
+
+      future.isCompleted must beFalse
+
+      addFileToWatchedDir(secondTestFileName)
+
+      Thread.sleep(waitToNoticeChange)
+      future.isCompleted must beFalse
+
+
+      addFileToWatchedDir(testFileName)
+      Thread.sleep(waitToNoticeChange)
+
+      future.isCompleted must beTrue
+
+    }
+  }