catch IndexControlRWIs_p error if RWI not connected

htroot/IndexControlRWIs_p.java

@@ -61,6 +61,7 @@ import net.yacy.peers.Seed;
 import net.yacy.repository.Blacklist;
 import net.yacy.repository.Blacklist.BlacklistType;
 import net.yacy.search.Switchboard;
+import net.yacy.search.SwitchboardConstants;
 import net.yacy.search.index.Segment;
 import net.yacy.search.query.QueryGoal;
 import net.yacy.search.query.QueryModifier;
@@ -331,7 +332,8 @@ public class IndexControlRWIs_p {
                 }
             }
 
-            // generate list
+            // generate list (if RWI connected, otherwise NPE)
+            if (sb.getConfigBool(SwitchboardConstants.CORE_SERVICE_RWI, true)) {
                 if ( post.containsKey("keyhashsimilar") ) {
                     try {
                         final Iterator<ReferenceContainer<WordReference>> containerIt =
@@ -360,6 +362,9 @@ public class IndexControlRWIs_p {
                         ConcurrentLog.logException(e);
                     }
                 }
+            } else {
+                prop.put("result", "RWI index not connected (see Index Sources & Targets -> <a href='IndexFederated_p.html'>Peer-to-Peer Operation</a>)");
+            }
 
             if ( post.containsKey("blacklist") ) {
                 final String blacklist = post.get("blacklist", "");