Differentiate on GET/POST methods for the stats servlet

ace-am/src/main/java/edu/umiacs/ace/stats/StatisticsServlet.java

 package edu.umiacs.ace.stats;
 
 import edu.umiacs.ace.util.EntityManagerServlet;
+import org.apache.log4j.Logger;
 
 import javax.persistence.EntityManager;
 import javax.servlet.RequestDispatcher;
@@ -17,22 +18,42 @@ import java.util.List;
  * Created by shake on 8/30/16.
  */
 public class StatisticsServlet extends EntityManagerServlet {
-    private static final Object[] HEADER = {"date", "collection", "group", "total_count", "size"};
+    private static final Logger LOG = Logger.getLogger(StatisticsServlet.class);
 
+    // General infos
+    private static final String GET = "GET";
+    private static final String SERVLET = "statistics.jsp";
+
+    // Query params
     private static final String AFTER = "after";
     private static final String BEFORE = "before";
     private static final String GROUP = "group";
     private static final String COLLECTION = "collection";
     private static final String CSV = "csv";
 
-
     @Override
     protected void processRequest(HttpServletRequest request, HttpServletResponse response, EntityManager em) throws ServletException, IOException {
+        // Differentiate on the request method
+        // GET - no query, just forward
+        // POST - query/csv handling
+        if (GET.equals(request.getMethod())) {
+            processGet(request, response);
+        } else {
+            processPost(request, response, em);
+        }
+    }
+
+    private void processGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+        RequestDispatcher dispatcher = request.getRequestDispatcher(SERVLET);
+        dispatcher.forward(request, response);
+    }
+
+    private void processPost(HttpServletRequest request, HttpServletResponse response, EntityManager em) throws ServletException, IOException {
+        String csv = getParameter(request, CSV, null);
+        String group = getParameter(request, GROUP, null);
         String after = getParameter(request, AFTER, null);
         String before = getParameter(request, BEFORE, null);
-        String group = getParameter(request, GROUP, null);
         String collection = getParameter(request, COLLECTION, null);
-        String csv = getParameter(request, CSV, null);
 
         SummaryQuery q = new SummaryQuery(group, after, before, collection);
 
@@ -42,7 +63,7 @@ public class StatisticsServlet extends EntityManagerServlet {
             List<IngestSummary> summary = q.getSummary();
             request.setAttribute("summary", summary);
 
-            RequestDispatcher dispatcher = request.getRequestDispatcher("statistics.jsp");
+            RequestDispatcher dispatcher = request.getRequestDispatcher(SERVLET);
             dispatcher.forward(request, response);
         } else {
             try {
@@ -51,8 +72,9 @@ public class StatisticsServlet extends EntityManagerServlet {
                 response.setHeader("Content-Disposition", "attachment; filename=ingest-summary.csv");
                 q.writeToCsv(response.getOutputStream());
             } catch (SQLException e) {
-                e.printStackTrace();
+                LOG.error("Error with statistics query", e);
             }
         }
     }
+
 }