fix Crawler HostQueue release of stackfile

- close stackfile inputstream at end of ChunkIterator
This should solve startup delay while unfinished crawl jobs exist (maybe also too many open file situation)

source/net/yacy/kelondro/table/ChunkIterator.java

@@ -45,6 +45,7 @@ public class ChunkIterator extends LookAheadIterator<byte[]> implements Iterator
      * a ChunkIterator uses a BufferedInputStream to iterate through the file
      * and is therefore a fast option to get all elements in the file as a sequence
      * ATTENTION: before calling this class ensure that all file buffers are flushed
+     * ATTENTION: if the iterator is not read to the end or interrupted, close() must be called to release the InputStream
      * @param file: the file
      * @param recordsize: the size of the elements in the file
      * @param chunksize: the size of the chunks that are returned by next(). remaining bytes until the lenght of recordsize are skipped
@@ -64,6 +65,15 @@ public class ChunkIterator extends LookAheadIterator<byte[]> implements Iterator
         this.stream = new DataInputStream(new BufferedInputStream(new FileInputStream(file), 64 * 1024));
     }
 
+    /**
+     * Special close methode to release the used InputStream
+     * stream is automatically closed on last next(),
+     * close() needs only be called if iterator not read to the end ( hasNext() or next() has not returned null)
+    */
+    public void close() throws IOException {
+        this.stream.close();
+    }
+
     @Override
     public byte[] next0() {
         final byte[] chunk = new byte[chunksize];
@@ -82,6 +92,11 @@ public class ChunkIterator extends LookAheadIterator<byte[]> implements Iterator
             return chunk;
         } catch (final EOFException e) {
             // no real exception, this is the normal termination
+            try {
+                this.stream.close(); // close the underlaying inputstream
+            } catch (IOException ex) {
+                ConcurrentLog.logException(ex);
+            }
             return null;
         } catch (final IOException e) {
             ConcurrentLog.logException(e);

source/net/yacy/kelondro/table/Table.java

@@ -173,7 +173,7 @@ public class Table implements Index, Iterable<Row.Entry> {
             } else {
                 byte[] record;
                 key = new byte[rowdef.primaryKeyLength];
-                final Iterator<byte[]> ri = new ChunkIterator(tablefile, rowdef.objectsize, rowdef.objectsize);
+                final ChunkIterator ri = new ChunkIterator(tablefile, rowdef.objectsize, rowdef.objectsize);
                 while (ri.hasNext()) {
                     record = ri.next();
                     assert record != null;
@@ -188,6 +188,7 @@ public class Table implements Index, Iterable<Row.Entry> {
                             this.table.addUnique(this.taildef.newEntry(record, rowdef.primaryKeyLength, true));
                         } catch (final SpaceExceededException e) {
                             this.table = null;
+                            ri.close(); // close inputstream of chunkiterator
                             break;
                         }
                     } else {