private void initExpressionTree() throws MetaException {
        StringBuilder filterBuilder = new StringBuilder();
        int len = filterSpec.getFilters().size();
        List<String> filters = filterSpec.getFilters();
        for (int i = 0; i < len; i++) {
          filterBuilder.append('(');
          filterBuilder.append(filters.get(i));
          filterBuilder.append(')');
          if (i + 1 < len) {
            filterBuilder.append(" AND ");
          }
        }
        String filterStr = filterBuilder.toString();
        tree = PartFilterExprUtil.parseFilterTree(filterStr);
      }
GetHelper for returning db info using directSql/JDO.
@param dbName The Database Name
@param allowSql Whether or not we allow DirectSQL to perform this query.
@param allowJdo Whether or not we allow ORM to perform this query.
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/ObjectStore.java