added id-timer abstraction

src/clj/backtype/storm/util.clj

@@ -3,7 +3,7 @@
   (:import [java.util Map List Collection])
   (:import [java.io FileReader])
   (:import [backtype.storm Config])
-  (:import [backtype.storm.utils Time Container])
+  (:import [backtype.storm.utils Time Container ClojureTimerTask])
   (:import [java.util UUID])
   (:import [java.util.concurrent.locks ReentrantReadWriteLock])
   (:import [java.io File RandomAccessFile StringWriter PrintWriter])
@@ -12,6 +12,7 @@
   (:import [org.apache.commons.io FileUtils])
   (:import [org.apache.commons.exec ExecuteException])
   (:import [org.json.simple JSONValue])
+  (:import [java.util Timer])
   (:require [clojure.contrib [str-utils2 :as str]])
   (:require [clojure [set :as set]])
   (:use [clojure walk])
@@ -531,3 +532,28 @@
 
 (defn container-get [^Container container]
   (. container object))
+
+(defn mk-timer []
+  {:timer (Timer.) :scheduled (atom #{})})
+
+(defn scheduled? [timer id]
+  (contains? @(:scheduled timer) id))
+
+(defn schedule [timer id delay afn]
+  (when (scheduled? timer id)
+    (throw (IllegalArgumentException. "Cannot schedule an already scheduled id")))
+  (let [wrapped (fn [] (afn) (swap! (:scheduled timer) disj id))]
+    (.schedule ^Timer (:timer timer)
+              delay
+              (ClojureTimerTask. wrapped))
+    (swap! (:scheduled timer) conj id)
+    ))
+
+(defn schedule-if-free [timer id delay afn]
+  (if-not (scheduled? timer id)
+    (schedule timer id delay afn)
+    ))
+
+;; need a map from "states" to the corresponding event transition (transition can include a delay)
+;; {:rebalance {:delay 10 :action (fn [] ... :active)}
+;; {(fn [] ...)}}

src/jvm/backtype/storm/utils/ClojureTimerTask.java

@@ -0,0 +1,18 @@
+package backtype.storm.utils;
+
+import clojure.lang.IFn;
+import java.util.TimerTask;
+
+public class ClojureTimerTask extends TimerTask {
+    IFn _afn;
+
+    public ClojureTimerTask(IFn afn) {
+        super();
+        _afn = afn;
+    }
+
+    @Override
+    public void run() {
+        _afn.run();
+    }    
+}