Class DERPath

  • public class DERPath
    extends Object
    Describes paths to individual elements of an encoded DER object that may be addressed during parsing to associate a parsed element with a handler to handle that element. Consider the following production rule for a complex type that may be DER encoded:
         BankAccountSet ::= SET OF {
           account BankAccount
         BankAccount ::= SEQUENCE OF {
           accountNumber OCTET STRING,
           accountName OCTET STRING,
           accountType AccountType,
           balance REAL
         AccountType ::= ENUM {
           checking (0),
           savings (1)

    Given an instance of BankAccountSet with two elements, the path to the balance of each bank account in the set is given by the following expression:


    Individual child elements can be accessed by explicitly mentioning the index of the item relative to its parent. For example, the second bank account in the set can be accessed as follows:


    Node names in DER paths are constrained to the following:

    See Also:
    • Field Detail


        private static final Pattern NODE_PATTERN
        General pattern for DER path nodes.

        private static final int HASH_CODE_SEED
        hash code seed.
        See Also:
        Constant Field Values
      • nodeStack

        private final Deque<DERPath.Node> nodeStack
        Describes the path as a FIFO set of nodes.
    • Constructor Detail

      • DERPath

        public DERPath()
        Creates an empty path specification.
      • DERPath

        public DERPath​(DERPath path)
        Copy constructor.
        path - to read nodes from
      • DERPath

        public DERPath​(String pathSpec)
        Creates a path specification from its string representation.
        pathSpec - string representation of a path, e.g. /SEQ[1]/CHOICE.
    • Method Detail

      • pushNode

        public DERPath pushNode​(String name)
        Appends a node to the path.
        name - of the path element to add
        This instance with new node appended.
      • pushNode

        public DERPath pushNode​(String name,
                                int index)
        Appends a node to the path with the given child index.
        name - of the path element to add
        index - child index
        This instance with new node appended.
      • peekNode

        public String peekNode()
        Examines the first node in the path without removing it.
        first node in the path or null if no nodes remain
      • popNode

        public String popNode()
        Removes the last node in the path.
        last node in the path or null if no more nodes remain.
      • getSize

        public int getSize()
        Gets the number of nodes in the path.
        node count.
      • isEmpty

        public boolean isEmpty()
        Determines whether the path contains any nodes.
        True if path contains 0 nodes, false otherwise.
      • hashCode

        public int hashCode()
        hashCode in class Object
      • toNode

        static DERPath.Node toNode​(String node)
        Converts a string representation of a node into a DERPath.Node object.
        node - String representation of node.
        Node corresponding to given string representation.
        IllegalArgumentException - for an invalid node name.