made the protocol navigator reversible

htroot/yacysearchtrailer.java

@@ -190,13 +190,20 @@ public class yacysearchtrailer {
             while (i < 20 && navigatorIterator.hasNext()) {
                 name = navigatorIterator.next().trim();
                 count = protocolNavigator.get(name);
-                nav = "/" + name;
+                nav = "%2F" + name;
                 queryStringForUrl = theQuery.queryStringForUrl();
                 p = queryStringForUrl.indexOf(nav);
-                prop.put("nav-protocols_element_" + i + "_on", 1);
-                prop.put(fileType, "nav-protocols_element_" + i + "_modifier", nav);
+                if (p < 0) {
+                    queryStringForUrl += "+" + nav;
+                    prop.put("nav-protocols_element_" + i + "_on", 1);
+                    prop.put(fileType, "nav-protocols_element_" + i + "_modifier", nav);
+                } else {
+                    queryStringForUrl = (queryStringForUrl.substring(0, p) + queryStringForUrl.substring(p + nav.length())).trim();
+                    prop.put("nav-protocols_element_" + i + "_on", 0);
+                    prop.put(fileType, "nav-protocols_element_" + i + "_modifier", nav);
+                }
                 prop.put(fileType, "nav-protocols_element_" + i + "_name", name);
-                prop.put(fileType, "nav-protocols_element_" + i + "_url", QueryParams.navurl(fileType.name().toLowerCase(), 0, theQuery, queryStringForUrl + "+" + nav, theQuery.urlMask.toString(), theQuery.navigators).toString());
+                prop.put(fileType, "nav-protocols_element_" + i + "_url", QueryParams.navurl(fileType.name().toLowerCase(), 0, theQuery, queryStringForUrl, theQuery.urlMask.toString(), theQuery.navigators).toString());
                 prop.put("nav-protocols_element_" + i + "_count", count);
                 prop.put("nav-protocols_element_" + i + "_nl", 1);
                 i++;

source/net/yacy/search/query/RWIProcess.java

@@ -835,9 +835,6 @@ public final class RWIProcess extends Thread
         if ( !this.query.navigators.equals("all") && this.query.navigators.indexOf("protocol", 0) < 0 ) {
             return new ClusteredScoreMap<String>();
         }
-        if ( this.protocolNavigator.sizeSmaller(2) ) {
-            this.protocolNavigator.clear(); // navigators with one entry are not useful
-        }
         return this.protocolNavigator;
     }