From 0ab47e41bc7a59d4814ca720a9009af03a3fc27f Mon Sep 17 00:00:00 2001
From: Simone Bordet <simone.bordet@gmail.com>
Date: Thu, 8 Mar 2012 11:42:14 +0100
Subject: [PATCH] Fixed NPE in case user agent pattern does not match.

---
 .../jetty/servlets/UserAgentFilter.java       | 43 ++++++++-----------
 1 file changed, 19 insertions(+), 24 deletions(-)

diff --git a/jetty-servlets/src/main/java/org/eclipse/jetty/servlets/UserAgentFilter.java b/jetty-servlets/src/main/java/org/eclipse/jetty/servlets/UserAgentFilter.java
index 71d60024c62..c489c9c21de 100644
--- a/jetty-servlets/src/main/java/org/eclipse/jetty/servlets/UserAgentFilter.java
+++ b/jetty-servlets/src/main/java/org/eclipse/jetty/servlets/UserAgentFilter.java
@@ -4,11 +4,11 @@
 // All rights reserved. This program and the accompanying materials
 // are made available under the terms of the Eclipse Public License v1.0
 // and Apache License v2.0 which accompanies this distribution.
-// The Eclipse Public License is available at 
+// The Eclipse Public License is available at
 // http://www.eclipse.org/legal/epl-v10.html
 // The Apache License v2.0 is available at
 // http://www.opensource.org/licenses/apache2.0.php
-// You may elect to redistribute this code under either of these licenses. 
+// You may elect to redistribute this code under either of these licenses.
 // ========================================================================
 
 package org.eclipse.jetty.servlets;
@@ -18,7 +18,6 @@ import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
-
 import javax.servlet.Filter;
 import javax.servlet.FilterChain;
 import javax.servlet.FilterConfig;
@@ -39,20 +38,20 @@ import javax.servlet.http.HttpServletRequest;
  * <dt>attribute</dt><dd>If set, then the request attribute of this name is set with the matched user agent string</dd>
  * <dt>cacheSize</dt><dd>The size of the user-agent cache, used to avoid reparsing of user agent strings. The entire cache is flushed
  * when this size is reached</dd>
- * <dt>userAgent</dt><dd>A regex {@link Pattern} to extract the essential elements of the user agent. 
+ * <dt>userAgent</dt><dd>A regex {@link Pattern} to extract the essential elements of the user agent.
  * The concatenation of matched pattern groups is used as the user agent name</dd>
- * <dl> 
+ * <dl>
  * An example value for pattern is <code>(?:Mozilla[^\(]*\(compatible;\s*+([^;]*);.*)|(?:.*?([^\s]+/[^\s]+).*)</code>. These two
  * pattern match the common compatibility user-agent strings and extract the real user agent, failing that, the first
- * element of the agent string is returned. 
- * 
+ * element of the agent string is returned.
+ *
  *
  */
 public class UserAgentFilter implements Filter
 {
     private static final String __defaultPattern = "(?:Mozilla[^\\(]*\\(compatible;\\s*+([^;]*);.*)|(?:.*?([^\\s]+/[^\\s]+).*)";
     private Pattern _pattern = Pattern.compile(__defaultPattern);
-    private Map _agentCache = new ConcurrentHashMap();
+    private Map<String, String> _agentCache = new ConcurrentHashMap<String, String>();
     private int _agentCacheSize=1024;
     private String _attribute;
 
@@ -71,7 +70,7 @@ public class UserAgentFilter implements Filter
     public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException
     {
         if (_attribute!=null && _pattern!=null)
-        {       
+        {
             String ua=getUserAgent(request);
             request.setAttribute(_attribute,ua);
         }
@@ -85,11 +84,11 @@ public class UserAgentFilter implements Filter
     public void init(FilterConfig filterConfig) throws ServletException
     {
         _attribute=filterConfig.getInitParameter("attribute");
-        
+
         String p=filterConfig.getInitParameter("userAgent");
         if (p!=null)
             _pattern=Pattern.compile(p);
-        
+
         String size=filterConfig.getInitParameter("cacheSize");
         if (size!=null)
             _agentCacheSize=Integer.parseInt(size);
@@ -101,7 +100,7 @@ public class UserAgentFilter implements Filter
         String ua=((HttpServletRequest)request).getHeader("User-Agent");
         return getUserAgent(ua);
     }
-    
+
     /* ------------------------------------------------------------ */
     /** Get UserAgent.
      * The configured agent patterns are used to match against the passed user agent string.
@@ -112,11 +111,10 @@ public class UserAgentFilter implements Filter
      */
     public String getUserAgent(String ua)
     {
-        if (ua==null)
+        if (ua == null)
             return null;
-        
-        String tag = (String)_agentCache.get(ua);
-        
+
+        String tag = _agentCache.get(ua);
 
         if (tag == null)
         {
@@ -131,7 +129,7 @@ public class UserAgentFilter implements Filter
                         {
                             String group = matcher.group(g);
                             if (group != null)
-                                tag = tag == null?group:(tag + group);
+                                tag = tag == null ? group : tag + group;
                         }
                     }
                     else
@@ -140,18 +138,15 @@ public class UserAgentFilter implements Filter
                     }
                 }
             }
-            else
-            {
+
+            if (tag == null)
                 tag = ua;
-            }
 
             if (_agentCache.size() >= _agentCacheSize)
-            {
                 _agentCache.clear();
-            }
-            _agentCache.put(ua,tag);
-
+            _agentCache.put(ua, tag);
         }
+
         return tag;
     }
 }