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gnu.crypto.der
Class OID

java.lang.Object
  extended bygnu.crypto.der.OID
All Implemented Interfaces:
Cloneable, Comparable

public class OID
extends Object
implements Cloneable, Comparable

This immutable class represents an object identifier, or OID.

OIDs are represented as a series of hierarcical tokens, each of which is usually represented as a single, unsigned integer. The hierarchy works so that later tokens are considered within the group of earlier tokens. Thus, the OID for the Serpent block cipher, 1.3.6.1.4.1.11591.13.2, is maintained by the GNU project, whose OID is 1.3.6.1.4.1.11591 (which is, in turn, part of bigger, more general bodies; the topmost, 1, stands for the OIDs assigned by the International Standards Organization, ISO).

OIDs can be represented in a variety of ways, including the dotted-decimal form we use here.

OIDs may be relative, in which case the first two elements of the OID are omitted.

Author:
Casey Marshall (rsdio@metastatic.org)

Constructor Summary
OID(byte[] encoded)
          Construct a new OID from the given DER bytes.
OID(byte[] encoded, boolean relative)
          Construct a new OID from the given DER bytes.
OID(InputStream derIn, int len)
          Construct a new OID from the DER bytes in an input stream.
OID(InputStream derIn, int len, boolean relative)
          Construct a new OID from the DER bytes in an input stream.
OID(int[] components)
          Create a new OID from the given byte array.
OID(int[] components, boolean relative)
          Create a new OID from the given byte array.
OID(String strRep)
          Create a new OID from the given dotted-decimal representation.
OID(String strRep, boolean relative)
          Create a new OID from the given dotted-decimal representation.
 
Method Summary
 Object clone()
          Returns a copy of this OID.
 int compareTo(Object o)
          Compares this OID to another.
 boolean equals(Object o)
          Tests whether or not this OID equals another.
 OID getChild(int id)
           
 byte[] getDER()
          Get the DER encoding of this OID, minus the tag and length fields.
 int[] getIDs()
          Return the numeric IDs of this OID.
 OID getParent()
          Get the parent OID of this OID.
 OID getRoot()
          Get the root OID of this OID.
 int hashCode()
          Computes a hash code for this OID.
 boolean isRelative()
           
 String toString()
          Returns the value of this OID in dotted-decimal format.
 
Methods inherited from class java.lang.Object
finalize, getClass, notify, notifyAll, wait, wait, wait
 

Constructor Detail

OID

public OID(int[] components)
Create a new OID from the given byte array. The argument (which can neither be null nor zero-length) is copied to prevent subsequent modification.

Parameters:
components - The numeric IDs.
Throws:
IllegalArgumentException - If components is null or empty.

OID

public OID(int[] components,
           boolean relative)
Create a new OID from the given byte array. The argument (which can neither be null nor zero-length) is copied to prevent subsequent modification.

Parameters:
components - The numeric IDs.
relative - The relative flag.
Throws:
IllegalArgumentException - If components is null or empty.

OID

public OID(String strRep)
Create a new OID from the given dotted-decimal representation.

Parameters:
strRep - The string representation of the OID.
Throws:
IllegalArgumentException - If the string does not contain at least one integer.
NumberFormatException - If the string does not contain only numbers and periods ('.').

OID

public OID(String strRep,
           boolean relative)
Create a new OID from the given dotted-decimal representation.

Parameters:
strRep - The string representation of the OID.
relative - The relative flag.
Throws:
IllegalArgumentException - If the string does not contain at least one integer.
NumberFormatException - If the string does not contain only numbers and periods ('.').

OID

public OID(InputStream derIn,
           int len)
    throws IOException
Construct a new OID from the DER bytes in an input stream. This method does not read the tag or the length field from the input stream, so the caller must supply the number of octets in this OID's encoded form.

Parameters:
derIn - The DER input stream.
len - The number of bytes in the encoded form.
Throws:
IOException - If an error occurs reading the OID.

OID

public OID(InputStream derIn,
           int len,
           boolean relative)
    throws IOException
Construct a new OID from the DER bytes in an input stream. This method does not read the tag or the length field from the input stream, so the caller must supply the number of octets in this OID's encoded form.

Parameters:
derIn - The DER input stream.
len - The number of bytes in the encoded form.
relative - The relative flag.
Throws:
IOException - If an error occurs reading the OID.

OID

public OID(byte[] encoded)
    throws IOException
Construct a new OID from the given DER bytes.

Parameters:
encoded - The DER encoded OID.
Throws:
IOException - If an error occurs reading the OID.

OID

public OID(byte[] encoded,
           boolean relative)
    throws IOException
Construct a new OID from the given DER bytes.

Parameters:
encoded - The encoded relative OID.
relative - The relative flag.
Method Detail

getIDs

public int[] getIDs()
Return the numeric IDs of this OID. The value returned is copied to prevent modification.

Returns:
The IDs in a new integer array.

getDER

public byte[] getDER()
Get the DER encoding of this OID, minus the tag and length fields.

Returns:
The DER bytes.

getParent

public OID getParent()
Get the parent OID of this OID. That is, if this OID is "1.2.3.4", then the parent OID will be "1.2.3". If this OID is a top-level OID, this method returns null.

Returns:
The parent OID, or null.

getChild

public OID getChild(int id)

getRoot

public OID getRoot()
Get the root OID of this OID. That is, the first two components.

Returns:
The root OID.

isRelative

public boolean isRelative()

clone

public Object clone()
Returns a copy of this OID.

Returns:
The copy.

toString

public String toString()
Returns the value of this OID in dotted-decimal format.

Returns:
The string representation.

hashCode

public int hashCode()
Computes a hash code for this OID.

Returns:
The hash code.

equals

public boolean equals(Object o)
Tests whether or not this OID equals another.

Returns:
Whether or not this OID equals the other.

compareTo

public int compareTo(Object o)
Compares this OID to another. The comparison is essentially lexicographic, where the two OIDs are compared until their first difference, then that difference is returned. If one OID is shorter, but all elements equal between the two for the shorter length, then the shorter OID is lesser than the longer.

Specified by:
compareTo in interface Comparable
Parameters:
o - The object to compare.
Returns:
An integer less than, equal to, or greater than zero if this object is less than, equal to, or greater than the argument.
Throws:
ClassCastException - If o is not an OID.

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