complete TODO: getFileExtension handle dot in query part

+ testcase

source/net/yacy/cora/document/id/MultiProtocolURL.java

@@ -838,7 +838,7 @@ public class MultiProtocolURL implements Serializable, Comparable<MultiProtocolU
      * @return extension or ""
      */
     public static String getFileExtension(final String fileName) {
-        final int p = fileName.lastIndexOf('.');
+        int p = fileName.lastIndexOf('.');
         if (p < 0) return "";
         final int q = fileName.lastIndexOf('?');
         if (q < 0) {
@@ -846,7 +846,8 @@ public class MultiProtocolURL implements Serializable, Comparable<MultiProtocolU
         }
         // check last dot in query part
         if (p > q) {
-            return ""; // TODO: last . after ?  (file.ext?param=one.txt)
+            p = fileName.lastIndexOf('.', q);
+            if (p < 0) return "";
         }
         return fileName.substring(p + 1, q).toLowerCase();
     }

test/net/yacy/cora/document/id/MultiProtocolURLTest.java

@@ -3,6 +3,7 @@ package net.yacy.cora.document.id;
 import static org.junit.Assert.*;
 
 import java.net.MalformedURLException;
+import java.util.HashMap;
 import java.util.LinkedHashMap;
 import java.util.Map;
 import java.util.TreeSet;
@@ -192,6 +193,26 @@ public class MultiProtocolURLTest {
             System.out.println(" -> " + resultUrl.toNormalform(false));
         }
     }
+
+     /**
+     * Test of getFileExtension method, of class MultiProtocolURL.
+     */
+    @Test
+    public void testGetFileExtension() throws MalformedURLException {
+        Map<String, String> testurls = new HashMap<String, String>();
+        //  key=testurl, value=result
+        testurls.put("path/file.xml","xml"); // easiest
+        testurls.put("path/file?h.pdf",""); // file w/o extension
+        testurls.put("file.html?param=h.pdf","html"); // dot in query part
+        testurls.put("url?param=h.pdf",""); // dot in query part
+        testurls.put("file.html?param", "html");
+        testurls.put("/path/","");
+        for (String s : testurls.keySet()) {
+            System.out.println("test getFileExtension: " + s + " -> " + testurls.get(s));
+            String result = MultiProtocolURL.getFileExtension(s);
+            assertEquals(testurls.get(s),result);
+        }
+    }
 }