Avoid NPE if no u-a header

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1074159 13f79535-47bb-0310-9956-ffa450edef68

diff --git a/java/org/apache/catalina/valves/CrawlerSessionManagerValve.java b/java/org/apache/catalina/valves/CrawlerSessionManagerValve.java
index b2c5880..c0f8881 100644 (file)
--- a/java/org/apache/catalina/valves/CrawlerSessionManagerValve.java
+++ b/java/org/apache/catalina/valves/CrawlerSessionManagerValve.java
@@ -125,10 +125,13 @@ public class CrawlerSessionManagerValve extends ValveBase {
 
             // Is this a crawler - cheack the UA headers
             Enumeration<String> uaHeaders = request.getHeaders("user-agent");
-            String uaHeader = uaHeaders.nextElement();
+            String uaHeader = null;
+            if (uaHeaders.hasMoreElements()) {
+                uaHeader = uaHeaders.nextElement();
+            }
             
             // If more than one UA header - assume not a bot
-            if (!uaHeaders.hasMoreElements()) {
+            if (uaHeader != null && !uaHeaders.hasMoreElements()) {
 
                 if (log.isDebugEnabled()) {
                     log.debug(request.hashCode() + ": UserAgent=" + uaHeader);