code: public int getPathConstraint() {
  
          int pathLength = Integer.MAX_VALUE;
          try {
              for (int i=0; i<this.certChain.length; i++) {
                  int length = BouncyCastleUtil.getProxyPathConstraint(this.certChain[i]);
                  // if length is one, then no proxy cert extension exists, so
                  // path length is -1
                  if (length == -1) {
                      length = Integer.MAX_VALUE;
                  }
                  if (length < pathLength) {
                      pathLength = length;
                  }
              }
          } catch (Exception e) {
              logger.warn("Error retrieving path length.", e);
              pathLength = -1;
          }
          return pathLength;
      }
docs: Returns the path length constraint. The shortest length in the chain of
  certificates is returned as the credential's path length.
  
  @return The path length constraint of the credential. -1 is any error
  occurs.