org.gwtwidgets.server.spring.ServletUtils.java Source code

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Here is the source code for org.gwtwidgets.server.spring.ServletUtils.java

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/*
 * 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 org.gwtwidgets.server.spring;

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

import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;

/**
 * Utility class that allows access to the invoking servlet request and
 * response, which are stored in a thread local variable of the invoking thread.
 * 
 * @author George Georgovassilis, g.georgovassilis[at]gmail.com
 * 
 */
public class ServletUtils {

    private static ThreadLocal<HttpServletResponse> servletResponse = new ThreadLocal<HttpServletResponse>();

    /**
     * Adjusts HTTP headers so that browsers won't cache response.
     * @param response
     * For more background see <a href="http://www.onjava.com/pub/a/onjava/excerpt/jebp_3/index2.html">this</a>.
     */
    public static void disableResponseCaching(HttpServletResponse response) {
        response.setHeader("Expires", "Sat, 1 January 2000 12:00:00 GMT");
        response.setHeader("Cache-Control", "no-store, no-cache, must-revalidate");
        response.addHeader("Cache-Control", "post-check=0, pre-check=0");
        response.setHeader("Pragma", "no-cache");
    }

    /**
     * Return the request which invokes the service. Valid only if used in the
     * dispatching thread.
     * @return the servlet request
     */
    public static HttpServletRequest getRequest() {
        return ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes()).getRequest();
    }

    /**
     * Return the response which accompanies the request. Valid only if used in
     * the dispatching thread.
     * 
     * @return the servlet response
     */
    public static HttpServletResponse getResponse() {
        return servletResponse.get();
    }

    /**
     * Assign the current servlet request to a thread local variable. Valid only
     * if used inside the invoking thread scope.
     * @deprecated Does not perform any operation
     * @param request
     */
    public static void setRequest(HttpServletRequest request) {
        throw new RuntimeException("setRequest has been deprecated");
    }

    /**
     * Assign the current servlet response to a thread local variable. Valid
     * only if used inside the invoking thread scope.
     * 
     * @param response
     */
    public static void setResponse(HttpServletResponse response) {
        servletResponse.set(response);
    }

}