Make the slave availability strategy actually do stuff!

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@9353 71c3de6d-444a-0410-be80-ed276b4c234a

core/src/main/java/hudson/model/SlaveReconnectionWork.java

 package hudson.model;
 
 import hudson.model.Slave.ComputerImpl;
+import static hudson.model.SlaveAvailabilityStrategy.*;
 import hudson.triggers.SafeTimerTask;
 
+import java.util.Map;
+import java.util.WeakHashMap;
+
 /**
  * Periodically checks the slaves and try to reconnect dead slaves.
  *
@@ -10,12 +14,25 @@ import hudson.triggers.SafeTimerTask;
  */
 public class SlaveReconnectionWork extends SafeTimerTask {
     protected void doRun() {
-        for(Slave s : Hudson.getInstance().getSlaves()) {
-            ComputerImpl c = s.getComputer();
-            if(c==null) // shouldn't happen, but let's be defensive
-                continue;
-            if(c.isOffline() && c.isStartSupported())
-                c.tryReconnect();
+        // use a weak hashmap
+        Map<Slave, Long> nextCheck = new WeakHashMap<Slave, Long>();
+        for (Slave s : Hudson.getInstance().getSlaves()) {
+            if (!nextCheck.containsKey(s) || System.currentTimeMillis() > nextCheck.get(s)) {
+                final Queue queue = Hudson.getInstance().getQueue();
+                boolean hasJob = false;
+                for (Executor exec: s.getComputer().getExecutors()) {
+                    if (!exec.isIdle()) {
+                        hasJob = true;
+                        break;
+                    }
+                }
+                // TODO get only the items from the queue that can apply to this slave
+                State state = new State(queue.getItems().length > 0, hasJob);
+                // at the moment I don't trust strategies to wait more than 60 minutes
+                // strategies need to wait at least one minute
+                final long waitInMins = Math.min(1, Math.max(60, s.getAvailabilityStrategy().check(s, state)));
+                nextCheck.put(s, System.currentTimeMillis() + 60 * 1000 * waitInMins);
+            }
         }
     }
 }