doc improvement

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@13534 71c3de6d-444a-0410-be80-ed276b4c234a

core/src/main/java/hudson/node_monitors/AbstractNodeMonitorDescriptor.java

@@ -64,7 +64,10 @@ public abstract class AbstractNodeMonitorDescriptor<T> extends Descriptor<NodeMo
     protected abstract T monitor(Computer c) throws IOException,InterruptedException;
 
     /**
-     * Obtains the monitoring result.
+     * Obtains the monitoring result currently available, or null if no data is available.
+     *
+     * <p>
+     * If no data is available, a background task to collect data will be started.
      */
     public T get(Computer c) {
         if(record==null) {