Issue #1050

jetty-servlet/src/main/java/org/eclipse/jetty/servlet/FilterHolder.java

@@ -109,32 +109,37 @@ public void doStart()
     @Override
     public void initialize() throws Exception
     {
-        super.initialize();
-
-        if (_filter==null)
+        if (!_initialized)
         {
-            try
-            {
-                ServletContext context=_servletHandler.getServletContext();
-                _filter=(context instanceof ServletContextHandler.Context)
-                    ?((ServletContextHandler.Context)context).createFilter(getHeldClass())
-                    :getHeldClass().newInstance();
-            }
-            catch (ServletException se)
+            super.initialize();
+
+            if (_filter==null)
             {
-                Throwable cause = se.getRootCause();
-                if (cause instanceof InstantiationException)
-                    throw (InstantiationException)cause;
-                if (cause instanceof IllegalAccessException)
-                    throw (IllegalAccessException)cause;
-                throw se;
+                try
+                {
+                    ServletContext context=_servletHandler.getServletContext();
+                    _filter=(context instanceof ServletContextHandler.Context)
+                            ?((ServletContextHandler.Context)context).createFilter(getHeldClass())
+                            :getHeldClass().newInstance();
+                }
+                catch (ServletException se)
+                {
+                    Throwable cause = se.getRootCause();
+                    if (cause instanceof InstantiationException)
+                        throw (InstantiationException)cause;
+                    if (cause instanceof IllegalAccessException)
+                        throw (IllegalAccessException)cause;
+                    throw se;
+                }
             }
-        }
 
-        _config=new Config();
-        if (LOG.isDebugEnabled())
-            LOG.debug("Filter.init {}",_filter);
-        _filter.init(_config);
+            _config=new Config();
+            if (LOG.isDebugEnabled())
+                LOG.debug("Filter.init {}",_filter);
+            _filter.init(_config);
+        }
+
+        _initialized = true;
     }
 
 
@@ -158,6 +163,7 @@ public void doStop()
             _filter=null;
 
         _config=null;
+        _initialized = false;
         super.doStop();
     }
 

jetty-servlet/src/main/java/org/eclipse/jetty/servlet/Holder.java

@@ -53,6 +53,7 @@ public class Holder<T> extends BaseHolder<T>
     protected String _displayName;
     protected boolean _asyncSupported;
     protected String _name;
+    protected boolean _initialized = false;
 
 
     /* ---------------------------------------------------------------- */

jetty-servlet/src/main/java/org/eclipse/jetty/servlet/ServletHolder.java

@@ -73,7 +73,6 @@ public class ServletHolder extends Holder<Servlet> implements UserIdentity.Scope
     private static final Logger LOG = Log.getLogger(ServletHolder.class);
     private int _initOrder = -1;
     private boolean _initOnStartup=false;
-    private boolean _initialized = false;
     private Map<String, String> _roleMap;
     private String _forcedPath;
     private String _runAsRole;
@@ -410,7 +409,8 @@ public void doStart()
     public void initialize ()
     throws Exception
     {
-        if(!_initialized){
+        if(!_initialized)
+        {
             super.initialize();
             if (_extInstance || _initOnStartup)
             {

jetty-servlet/src/test/java/org/eclipse/jetty/servlet/FilterHolderTest.java

@@ -0,0 +1,103 @@
+//
+//  ========================================================================
+//  Copyright (c) 1995-2016 Mort Bay Consulting Pty. Ltd.
+//  ------------------------------------------------------------------------
+//  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
+//      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.
+//  ========================================================================
+//
+
+
+package org.eclipse.jetty.servlet;
+
+import static org.junit.Assert.*;
+
+import java.io.IOException;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import javax.servlet.Filter;
+import javax.servlet.FilterChain;
+import javax.servlet.FilterConfig;
+import javax.servlet.ServletException;
+import javax.servlet.ServletRequest;
+import javax.servlet.ServletResponse;
+
+import org.eclipse.jetty.util.log.StacklessLogging;
+import org.junit.Test;
+
+/**
+ * FilterHolderTest
+ *
+ *
+ */
+public class FilterHolderTest
+{
+
+    @Test
+    public void testInitialize()
+    throws Exception
+    {
+        ServletHandler handler = new ServletHandler();
+
+        final AtomicInteger counter = new AtomicInteger(0);
+        Filter filter = new Filter ()
+                {
+                    @Override
+                    public void init(FilterConfig filterConfig) throws ServletException
+                    {   
+                        counter.incrementAndGet();
+                    }
+
+                    @Override
+                    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException
+                    {  
+                    }
+
+                    @Override
+                    public void destroy()
+                    { 
+                    }
+
+                };
+
+      FilterHolder fh = new FilterHolder();
+      fh.setServletHandler(handler);
+
+      fh.setName("xx");
+      fh.setFilter(filter);
+
+      try (StacklessLogging stackless = new StacklessLogging(FilterHolder.class))
+      {
+          fh.initialize();
+          fail("Not started");
+      }
+      catch (Exception e)
+      {
+          //expected
+      }
+
+       fh.start();
+       fh.initialize();
+       assertEquals(1, counter.get());
+
+       fh.initialize();
+       assertEquals(1, counter.get());
+
+       fh.stop();
+       assertEquals(1, counter.get());
+       fh.start();
+       assertEquals(1, counter.get());
+       fh.initialize();
+       assertEquals(2, counter.get());
+    }
+
+}