--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gwt-client/src/main/java/org/dive4elements/river/client/server/filter/NoCacheFilter.java	Thu Apr 25 15:23:37 2013 +0200
@@ -0,0 +1,72 @@
+package org.dive4elements.river.client.server.filter;
+
+import java.io.IOException;
+import java.util.Date;
+
+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 javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+import org.apache.log4j.Logger;
+
+/** ServletFilter to avoid caching for GWTs *.nocache.* files. */
+public class NoCacheFilter implements Filter {
+
+    private static final long DAY = 86400000L;
+
+    private static final String NO_CACHE = ".nocache.";
+
+    private static Logger log = Logger.getLogger(NoCacheFilter.class);
+
+    /**
+     * Initialize.
+     */
+    @Override
+    public void init(FilterConfig config)
+    throws ServletException
+    {
+    }
+
+
+    /**
+     * Called when filter in chain invoked.
+     * @param req request to servlet
+     * @param resp response of servlet
+     * @param chain the filter chain
+     */
+    @Override
+    public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain)
+    throws IOException, ServletException
+    {
+        HttpServletRequest httpreq = (HttpServletRequest)req;
+        String uri = httpreq.getRequestURI();
+
+        if (uri.contains(NO_CACHE)) {
+            log.debug("Set no-cache for " + uri);
+
+            Date now = new Date();
+            HttpServletResponse httpresp = (HttpServletResponse)resp;
+            httpresp.setDateHeader("Date", now.getTime());
+            httpresp.setDateHeader("Expires", now.getTime() - DAY);
+            httpresp.setHeader("Pragma", "no-cache");
+            httpresp.setHeader("Cache-control",
+                    "no-cache, no-store, must-revalidate");
+        }
+
+        chain.doFilter(req, resp);
+    }
+
+
+    /**
+     * Do nothing at destruction.
+     */
+    @Override
+    public void destroy() {
+    }
+}
+// vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :