jp.xet.uncommons.web.UsernameLogFilter.java Source code

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Here is the source code for jp.xet.uncommons.web.UsernameLogFilter.java

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/*
 * Copyright 2011 Daisuke Miyamoto.
 * Created on 2011/11/09
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific language
 * governing permissions and limitations under the License.
 */
package jp.xet.uncommons.web;

import java.io.IOException;

import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.slf4j.MDC;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.context.SecurityContext;
import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.web.filter.OncePerRequestFilter;

/**
 * ??? SLF4J ??????ServletFilter
 * 
 * @since 1.0
 * @version $Id$
 * @author daisuke
 */
public class UsernameLogFilter extends OncePerRequestFilter {

    private static final String USER_KEY = "username";

    @Override
    public void destroy() {
    }

    @Override
    protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response,
            FilterChain filterChain) throws ServletException, IOException {
        SecurityContext ctx = SecurityContextHolder.getContext();
        Authentication auth = ctx.getAuthentication();

        boolean successfulRegistration = false;
        if (auth != null) {
            String username = auth.getName();
            successfulRegistration = registerUsername(username);
        }

        try {
            filterChain.doFilter(request, response);
        } finally {
            if (successfulRegistration) {
                MDC.remove(USER_KEY);
            }
        }
    }

    /**
     * Register the user in the {@link MDC} under {@link #USER_KEY}.
     * 
     * @param username the username
     * @return true id the user can be successfully registered
     */
    private boolean registerUsername(String username) {
        if (username != null && username.trim().length() > 0) {
            MDC.put(USER_KEY, username);
            return true;
        }
        return false;
    }
}