Improve documentation, disable cleanup if heartbeat interval nonpositive, change default heartbeat interval from 500 to 300, some logging on client side (#9265)

client/src/com/vaadin/terminal/gwt/client/ApplicationConfiguration.java

@@ -290,6 +290,10 @@ public class ApplicationConfiguration implements EntryPoint {
         return rootId;
     }
 
+    /**
+     * @return The interval in seconds between heartbeat requests, or a
+     *         non-positive number if heartbeat is disabled.
+     */
     public int getHeartbeatInterval() {
         return heartbeatInterval;
     }

client/src/com/vaadin/terminal/gwt/client/ApplicationConnection.java

@@ -2524,19 +2524,23 @@ public class ApplicationConnection {
     }
 
     /**
-     * Schedules a heartbeat request.
+     * Schedules a heartbeat request to occur after the configured heartbeat
+     * interval elapses if the interval is a positive number. Otherwise, does
+     * nothing.
      * 
      * @see #sendHeartbeat()
+     * @see ApplicationConfiguration#getHeartbeatInterval()
      */
-    private void scheduleHeartbeat() {
-        final int interval = 1000 * getConfiguration().getHeartbeatInterval();
+    protected void scheduleHeartbeat() {
+        final int interval = getConfiguration().getHeartbeatInterval();
         if (interval > 0) {
+            VConsole.log("Scheduling heartbeat in " + interval + " seconds");
             new Timer() {
                 @Override
                 public void run() {
                     sendHeartbeat();
                 }
-            }.schedule(interval);
+            }.schedule(interval * 1000);
         }
     }
 
@@ -2552,7 +2556,7 @@ public class ApplicationConnection {
      * @see #scheduleHeartbeat()
      * @see com.vaadin.ui.Root#heartbeat()
      */
-    private void sendHeartbeat() {
+    protected void sendHeartbeat() {
         final String uri = addGetParameters(
                 translateVaadinUri(ApplicationConstants.APP_PROTOCOL_PREFIX
                         + ApplicationConstants.HEARTBEAT_REQUEST_PATH),
@@ -2568,6 +2572,7 @@ public class ApplicationConnection {
                 int status = response.getStatusCode();
                 if (status == Response.SC_OK) {
                     // TODO Permit retry in some error situations
+                    VConsole.log("Heartbeat response OK");
                     scheduleHeartbeat();
                 } else {
                     VConsole.error("Heartbeat request failed with status code "
@@ -2585,6 +2590,7 @@ public class ApplicationConnection {
         rb.setCallback(callback);
 
         try {
+            VConsole.log("Sending heartbeat request...");
             rb.send();
         } catch (RequestException re) {
             callback.onError(null, re);

server/src/com/vaadin/Application.java

@@ -2448,7 +2448,9 @@ public class Application implements Terminal.ErrorListener, Serializable {
     /**
      * Removes all those roots from the application whose last heartbeat
      * occurred more than {@link #getHeartbeatTimeout()} seconds ago. Close
-     * events are fired for the removed roots.
+     * events are fired for the removed roots. If
+     * <code>getHeartbeatTimeout()</code> returns a nonpositive number, no
+     * cleanup is performed.
      * <p>
      * Called by the framework at the end of every request.
      * 
@@ -2459,13 +2461,15 @@ public class Application implements Terminal.ErrorListener, Serializable {
      * @since 7.0.0
      */
     public void closeInactiveRoots() {
-        long now = System.currentTimeMillis();
-        for (Iterator<Root> i = roots.values().iterator(); i.hasNext();) {
-            Root root = i.next();
-            if (now - root.getLastHeartbeat() > 1000 * getHeartbeatTimeout()) {
-                i.remove();
-                retainOnRefreshRoots.values().remove(root.getRootId());
-                root.fireCloseEvent();
+        if (getHeartbeatTimeout() > 0) {
+            long now = System.currentTimeMillis();
+            for (Iterator<Root> i = roots.values().iterator(); i.hasNext();) {
+                Root root = i.next();
+                if (now - root.getLastHeartbeat() > 1000 * getHeartbeatTimeout()) {
+                    i.remove();
+                    retainOnRefreshRoots.values().remove(root.getRootId());
+                    root.fireCloseEvent();
+                }
             }
         }
     }
@@ -2478,7 +2482,8 @@ public class Application implements Terminal.ErrorListener, Serializable {
      * 
      * @since 7.0.0
      * 
-     * @return The heartbeat timeout in seconds.
+     * @return The heartbeat timeout in seconds or a nonpositive number if
+     *         timeout never occurs.
      */
     public int getHeartbeatTimeout() {
         // Permit three missed heartbeats before closing the root

server/src/com/vaadin/terminal/DeploymentConfiguration.java

@@ -155,7 +155,8 @@ public interface DeploymentConfiguration extends Serializable {
     public int getResourceCacheTime();
 
     /**
-     * Returns the number of seconds between heartbeat requests of a root.
+     * Returns the number of seconds between heartbeat requests of a root, or a
+     * non-negative number if heartbeat is disabled.
      * 
      * @return
      */

server/src/com/vaadin/terminal/gwt/server/AbstractDeploymentConfiguration.java

@@ -228,11 +228,11 @@ public abstract class AbstractDeploymentConfiguration implements
         try {
             heartbeatInterval = Integer
                     .parseInt(getApplicationOrSystemProperty(
-                            Constants.SERVLET_PARAMETER_HEARTBEAT_RATE, "500"));
+                            Constants.SERVLET_PARAMETER_HEARTBEAT_RATE, "300"));
         } catch (NumberFormatException e) {
             getLogger().warning(
                     Constants.WARNING_HEARTBEAT_INTERVAL_NOT_NUMERIC);
-            heartbeatInterval = 500;
+            heartbeatInterval = 300;
         }
     }