| 1 | // Copyright 2004-2007 Jean-Francois Poilpret |
| 2 | // |
| 3 | // Licensed under the Apache License, Version 2.0 (the "License"); |
| 4 | // you may not use this file except in compliance with the License. |
| 5 | // You may obtain a copy of the License at |
| 6 | // |
| 7 | // http://www.apache.org/licenses/LICENSE-2.0 |
| 8 | // |
| 9 | // Unless required by applicable law or agreed to in writing, software |
| 10 | // distributed under the License is distributed on an "AS IS" BASIS, |
| 11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 12 | // See the License for the specific language governing permissions and |
| 13 | // limitations under the License. |
| 14 | |
| 15 | package net.sourceforge.hiveutils.web.logging; |
| 16 | |
| 17 | import java.io.IOException; |
| 18 | |
| 19 | import javax.servlet.Filter; |
| 20 | import javax.servlet.FilterChain; |
| 21 | import javax.servlet.FilterConfig; |
| 22 | import javax.servlet.ServletException; |
| 23 | import javax.servlet.ServletRequest; |
| 24 | import javax.servlet.ServletResponse; |
| 25 | import javax.servlet.http.HttpServletRequest; |
| 26 | |
| 27 | import org.apache.log4j.NDC; |
| 28 | |
| 29 | /** |
| 30 | * Filter that will add a Diagnostic Context (NDC) to the current stack of NDC |
| 31 | * of log4j. This can be used for any purpose. |
| 32 | * This default implementation pushes no NDC at all but can be overridden to |
| 33 | * push any context. |
| 34 | * |
| 35 | * @author Jean-Francois Poilpret |
| 36 | */ |
| 37 | public class LoggingContextInitFilter implements Filter |
| 38 | { |
| 39 | public void init(FilterConfig filterConfig) |
| 40 | { |
| 41 | } |
| 42 | |
| 43 | public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) |
| 44 | throws IOException, ServletException |
| 45 | { |
| 46 | String context = getContext((HttpServletRequest) req); |
| 47 | if (context != null) |
| 48 | { |
| 49 | NDC.push(context); |
| 50 | } |
| 51 | try |
| 52 | { |
| 53 | chain.doFilter(req, res); |
| 54 | } |
| 55 | finally |
| 56 | { |
| 57 | if (context != null) |
| 58 | { |
| 59 | NDC.remove(); |
| 60 | } |
| 61 | } |
| 62 | } |
| 63 | |
| 64 | /** |
| 65 | * Returns the context to be pushed on the NDC stack. |
| 66 | * This context must be extracted from the current request. |
| 67 | * <p> |
| 68 | * By default, this method returns <code>null</code> (ie, no context pushed) |
| 69 | * but you would override it to push whatever is suitable (eg, the name of |
| 70 | * the user who sent the current request). |
| 71 | * @param req the current http request |
| 72 | * @return the context to be pushed on the NDC stack |
| 73 | */ |
| 74 | protected String getContext(HttpServletRequest req) |
| 75 | { |
| 76 | return null; |
| 77 | } |
| 78 | |
| 79 | public void destroy() |
| 80 | { |
| 81 | } |
| 82 | } |