fixed a deadlock during secondary remote search

source/net/yacy/kelondro/data/word/WordReferenceFactory.java

@@ -26,8 +26,10 @@
 
 package net.yacy.kelondro.data.word;
 
+import java.util.Collections;
 import java.util.Iterator;
 import java.util.Map;
+import java.util.SortedMap;
 import java.util.TreeMap;
 
 import net.yacy.cora.document.ASCII;
@@ -39,15 +41,18 @@ import net.yacy.kelondro.util.ByteBuffer;
 
 public class WordReferenceFactory implements ReferenceFactory<WordReference> {
 
+    @Override
     public WordReference produceSlow(final Entry e) {
         return new WordReferenceRow(e);
     }
     
+    @Override
     public WordReference produceFast(final WordReference r) {
         if (r instanceof WordReferenceVars) return r;
         return new WordReferenceVars(r);
     }
 
+    @Override
     public Row getRow() {
         return WordReferenceRow.urlEntryRow;
     }
@@ -110,8 +115,8 @@ public class WordReferenceFactory implements ReferenceFactory<WordReference> {
      * @param peerhash
      * @return
      */
-    public static final TreeMap<String, StringBuilder> decompressIndex(ByteBuffer ci, final String peerhash) {
-        TreeMap<String, StringBuilder> target = new TreeMap<String, StringBuilder>();
+    public static final SortedMap<String, StringBuilder> decompressIndex(ByteBuffer ci, final String peerhash) {
+        SortedMap<String, StringBuilder> target = Collections.synchronizedSortedMap(new TreeMap<String, StringBuilder>());
         // target is a mapping from url-hashes to a string of peer-hashes
         if (ci.byteAt(0) != '{' || ci.byteAt(ci.length() - 1) != '}') return target;
         //System.out.println("DEBUG-DECOMPRESS: input is " + ci.toString());

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

@@ -26,6 +26,7 @@
 
 package net.yacy.search.query;
 
+import java.util.Collections;
 import java.util.Iterator;
 import java.util.Map;
 import java.util.SortedMap;
@@ -516,8 +517,8 @@ public final class SearchEvent
         private final Semaphore trigger;
 
         public SecondarySearchSuperviser() {
-            this.abstractsCache = new TreeMap<String, SortedMap<String, StringBuilder>>();
-            this.checkedPeers = new TreeSet<String>();
+            this.abstractsCache = Collections.synchronizedSortedMap(new TreeMap<String, SortedMap<String, StringBuilder>>());
+            this.checkedPeers = Collections.synchronizedSortedSet(new TreeSet<String>());
             this.trigger = new Semaphore(0);
         }
 
@@ -527,16 +528,14 @@ public final class SearchEvent
          * @param wordhash
          * @param singleAbstract // a mapping from url-hashes to a string of peer-hashes
          */
-        public void addAbstract(final String wordhash, final TreeMap<String, StringBuilder> singleAbstract) {
+        public void addAbstract(final String wordhash, final SortedMap<String, StringBuilder> singleAbstract) {
             final SortedMap<String, StringBuilder> oldAbstract;
-            synchronized ( this.abstractsCache ) {
                 oldAbstract = this.abstractsCache.get(wordhash);
                 if ( oldAbstract == null ) {
                     // new abstracts in the cache
                     this.abstractsCache.put(wordhash, singleAbstract);
                     return;
                 }
-            }
             // extend the abstracts in the cache: join the single abstracts
             new Thread() {
                 @Override
@@ -544,14 +543,12 @@ public final class SearchEvent
                     for ( final Map.Entry<String, StringBuilder> oneref : singleAbstract.entrySet() ) {
                         final String urlhash = oneref.getKey();
                         final StringBuilder peerlistNew = oneref.getValue();
-                        synchronized ( oldAbstract ) {
                         final StringBuilder peerlistOld = oldAbstract.put(urlhash, peerlistNew);
                         if ( peerlistOld != null ) {
                             peerlistOld.append(peerlistNew);
                         }
                     }
                 }
-                }
             }.start();
             // abstractsCache.put(wordhash, oldAbstract); // put not necessary since it is sufficient to just change the value content (it stays assigned)
         }
@@ -567,7 +564,6 @@ public final class SearchEvent
             SortedMap<String, StringBuilder> urlPeerlist;
             int p;
             boolean hasURL;
-            synchronized ( this ) {
             final Iterator<Map.Entry<String, SortedMap<String, StringBuilder>>> i =
                 this.abstractsCache.entrySet().iterator();
             while ( i.hasNext() ) {
@@ -588,7 +584,6 @@ public final class SearchEvent
                     wordlist += word;
                 }
             }
-            }
             return wordlist;
         }