Port of github.com/polymer/polymer.

pkg/polymer/lib/job.dart

Index: pkg/polymer/lib/job.dart
diff --git a/pkg/polymer/lib/job.dart b/pkg/polymer/lib/job.dart
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+// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+library polymer.job;
+
+import 'dart:async' show Timer;
+
+/**
+ * Invoke [callback] in [wait], unless the job is re-registered,
+ * which resets the timer. For example:
+ *
+ *     _myJob = runJob(_myJob, callback, const Duration(milliseconds: 100));
+ *
+ * Returns a job handle which can be used to re-register a job.
+ */
+// Dart note: renamed to runJob to avoid conflict with instance member "job".
+Job runJob(Job job, void callback(), Duration wait) {
+  if (job != null) {
+    job.stop();
+  } else {
+    job = new Job();
+  }
+  job.go(callback, wait);
+  return job;
+}
+
+// TODO(jmesserly): it isn't clear to me what is supposed to be public API here.
+// Or what name we should use. "Job" is awfully generic.
+// (The type itself is not exported in Polymer.)
+class Job {
+  Function _callback;
+  Timer _timer;
+
+  void go(void callback(), Duration wait) {
+    this._callback = callback;
+    _timer = new Timer(wait, complete);
+  }
+
+  void stop() {
+    if (_timer != null) {
+      _timer.cancel();
+      _timer = null;
+    }
+  }
+
+  void complete() {
+    if (_timer != null) {
+      stop();
+      _callback();
+    }
+  }
+}