Don't lock session for checking request details (#12265)

Change-Id: Id3e2b250b6aea66859274e2a5d6046c4f80172c3

5 files changed, 47 insertions, 17 deletions

diff --git a/server/src/com/vaadin/server/BootstrapHandler.java b/server/src/com/vaadin/server/BootstrapHandler.java
index b21fdb0b74..f237d9edd4 100644
--- a/server/src/com/vaadin/server/BootstrapHandler.java
+++ b/server/src/com/vaadin/server/BootstrapHandler.java
@@ -146,14 +146,15 @@ public abstract class BootstrapHandler extends SynchronizedRequestHandler {
     }
 
     @Override
+    protected boolean canHandleRequest(VaadinRequest request) {
+        // We do not want to handle /APP requests here, instead let it fall
+        // through and produce a 404
+        return !ServletPortletHelper.isAppRequest(request);
+    }
+
+    @Override
     public boolean synchronizedHandleRequest(VaadinSession session,
             VaadinRequest request, VaadinResponse response) throws IOException {
-        if (ServletPortletHelper.isAppRequest(request)) {
-            // We do not want to handle /APP requests here, instead let it fall
-            // through and produce a 404
-            return false;
-        }
-
         try {
             // Update WebBrowser here only to make WebBrowser information
             // available in init for LegacyApplications
diff --git a/server/src/com/vaadin/server/SynchronizedRequestHandler.java b/server/src/com/vaadin/server/SynchronizedRequestHandler.java
index ac730dcecb..c695855d7d 100644
--- a/server/src/com/vaadin/server/SynchronizedRequestHandler.java
+++ b/server/src/com/vaadin/server/SynchronizedRequestHandler.java
@@ -32,6 +32,10 @@ public abstract class SynchronizedRequestHandler implements RequestHandler {
     @Override
     public boolean handleRequest(VaadinSession session, VaadinRequest request,
             VaadinResponse response) throws IOException {
+        if (!canHandleRequest(request)) {
+            return false;
+        }
+
         session.lock();
         try {
             return synchronizedHandleRequest(session, request, response);
@@ -62,4 +66,25 @@ public abstract class SynchronizedRequestHandler implements RequestHandler {
     public abstract boolean synchronizedHandleRequest(VaadinSession session,
             VaadinRequest request, VaadinResponse response) throws IOException;
 
+    /**
+     * Check whether a request may be handled by this handler. This can be used
+     * as an optimization to avoid locking the session just to investigate some
+     * method property. The default implementation just returns
+     * <code>true</code> which means that all requests will be handled by
+     * calling
+     * {@link #synchronizedHandleRequest(VaadinSession, VaadinRequest, VaadinResponse)}
+     * with the session locked.
+     * 
+     * @since 7.2
+     * @param request
+     *            the request to handle
+     * @return <code>true</code> if the request handling should continue once
+     *         the session has been locked; <code>false</code> if there's no
+     *         need to lock the session since the request would still not be
+     *         handled.
+     */
+    protected boolean canHandleRequest(VaadinRequest request) {
+        return true;
+    }
+
 }
diff --git a/server/src/com/vaadin/server/communication/HeartbeatHandler.java b/server/src/com/vaadin/server/communication/HeartbeatHandler.java
index 4c95859203..04cb1b5a25 100644
--- a/server/src/com/vaadin/server/communication/HeartbeatHandler.java
+++ b/server/src/com/vaadin/server/communication/HeartbeatHandler.java
@@ -43,6 +43,11 @@ import com.vaadin.ui.UI;
 public class HeartbeatHandler extends SynchronizedRequestHandler implements
         SessionExpiredHandler {
 
+    @Override
+    protected boolean canHandleRequest(VaadinRequest request) {
+        return ServletPortletHelper.isHeartbeatRequest(request);
+    }
+
     /**
      * Handles a heartbeat request for the given session. Reads the GET
      * parameter named {@link UIConstants#UI_ID_PARAMETER} to identify the UI.
@@ -53,10 +58,6 @@ public class HeartbeatHandler extends SynchronizedRequestHandler implements
     @Override
     public boolean synchronizedHandleRequest(VaadinSession session,
             VaadinRequest request, VaadinResponse response) throws IOException {
-        if (!ServletPortletHelper.isHeartbeatRequest(request)) {
-            return false;
-        }
-
         UI ui = session.getService().findUI(request);
         if (ui != null) {
             ui.setLastHeartbeatTimestamp(System.currentTimeMillis());
diff --git a/server/src/com/vaadin/server/communication/UIInitHandler.java b/server/src/com/vaadin/server/communication/UIInitHandler.java
index d4b0bc709f..e16e4f6cdd 100644
--- a/server/src/com/vaadin/server/communication/UIInitHandler.java
+++ b/server/src/com/vaadin/server/communication/UIInitHandler.java
@@ -56,12 +56,13 @@ public abstract class UIInitHandler extends SynchronizedRequestHandler {
     protected abstract boolean isInitRequest(VaadinRequest request);
 
     @Override
+    protected boolean canHandleRequest(VaadinRequest request) {
+        return isInitRequest(request);
+    }
+
+    @Override
     public boolean synchronizedHandleRequest(VaadinSession session,
             VaadinRequest request, VaadinResponse response) throws IOException {
-        if (!isInitRequest(request)) {
-            return false;
-        }
-
         StringWriter stringWriter = new StringWriter();
 
         try {
diff --git a/server/src/com/vaadin/server/communication/UidlRequestHandler.java b/server/src/com/vaadin/server/communication/UidlRequestHandler.java
index d52c5e9fe0..cf25910fa4 100644
--- a/server/src/com/vaadin/server/communication/UidlRequestHandler.java
+++ b/server/src/com/vaadin/server/communication/UidlRequestHandler.java
@@ -60,11 +60,13 @@ public class UidlRequestHandler extends SynchronizedRequestHandler implements
     }
 
     @Override
+    protected boolean canHandleRequest(VaadinRequest request) {
+        return ServletPortletHelper.isUIDLRequest(request);
+    }
+
+    @Override
     public boolean synchronizedHandleRequest(VaadinSession session,
             VaadinRequest request, VaadinResponse response) throws IOException {
-        if (!ServletPortletHelper.isUIDLRequest(request)) {
-            return false;
-        }
         UI uI = session.getService().findUI(request);
         if (uI == null) {
             // This should not happen but it will if the UI has been closed. We