add hash-based accessor

Author: baltzell

common-tools/clas-utils/src/main/java/org/jlab/utils/groups/IndexedList.java

@@ -326,11 +326,23 @@ public int getIndex(long hashcode, int order) {
             return (int) ((hashcode >> this.byteShifts[order]) & mask);
         }
 
+        /**
+         * Retrieves an array of the requested indices.
+         * 
+         * @param indices
+         * @return 
+         */
+        public int[] getIndices(long hashcode, int... indices) {
+            int[] ret = new int[indices.length];
+            for (int i=0; i<ret.length; i++)
+                ret[i] = getIndex(hashcode, i);
+            return ret;
+        }
+
         /**
          * Returns a formatted string representing all indices in the hash key.
          *
          * @param hashcode the encoded long key
-         * @param length the number of indices to extract
          * @return a string representation of the indices
          */
         public String getString(long hashcode) {