net.named_data.jndn.util

Class Common

java.lang.Object

net.named_data.jndn.util.Common

public class Common
extends Object

The Common class has static utility functions.

Field Summary

Fields

Modifier and Type	Field and Description
static int	MAX_NDN_PACKET_SIZE The practical limit of the size of a network-layer packet.

Constructor Summary

Constructors

Constructor and Description
Common()

Method Summary

Methods

Modifier and Type	Method and Description
static byte[]	base64Decode(String encoding) Decode the input as base64 using the appropriate base64Converter_ from establishBase64Converter(), for ANDROID or Java 7+.
static String	base64Encode(byte[] input) Encode the input as base64 using the appropriate base64Converter_ from establishBase64Converter(), for ANDROID or Java 7+.
static byte[]	computeHmacWithSha256(byte[] key, ByteBuffer data) Compute the HMAC with SHA-256 of data, as defined in http://tools.ietf.org/html/rfc2104#section-2 .
static byte[]	digestSha256(ByteBuffer data) Compute the sha-256 digest of data.
static double	getNowMilliseconds() Get the current time in milliseconds.
static Random	getRandom() Get the library-wide random number generator.
static void	setRandom(Random randomNumberGenerator) Set the library-wide random number generator; this method will only allow the generator to be set once.
static String	toHex(byte[] buffer) Return a hex string of the contents of buffer.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

MAX_NDN_PACKET_SIZE

public static final int MAX_NDN_PACKET_SIZE

The practical limit of the size of a network-layer packet. If a packet is larger than this, the library or application MAY drop it. This constant is defined in this low-level class so that internal code can use it, but applications should use the static API method Face.getMaxNdnPacketSize() which is equivalent.

See Also:

Constant Field Values

Constructor Detail

Common

public Common()

Method Detail

getNowMilliseconds

public static double getNowMilliseconds()

Get the current time in milliseconds.

Returns:

The current time in milliseconds since 1/1/1970, including fractions of a millisecond.

getRandom

public static Random getRandom()

Get the library-wide random number generator. This method is synchronized so that multiple accesses to the generator when a generator is not yet set will not throw an UnsupportedOperationException

Returns:

the random number generator set in setRandom(Random) or (by default) a SecureRandom

setRandom

public static void setRandom(Random randomNumberGenerator)

Set the library-wide random number generator; this method will only allow the generator to be set once. Additionally, this method is thread-safe in that it guarantees that only the first caller will be able to set the generator.

Parameters:

randomNumberGenerator - the random number generator

Throws:

UnsupportedOperationException - if a user attempts to set the generator a second time

digestSha256

public static byte[] digestSha256(ByteBuffer data)

Compute the sha-256 digest of data.

Parameters:

data - The input byte buffer. This does not change the position.

Returns:

The digest.

computeHmacWithSha256

public static byte[] computeHmacWithSha256(byte[] key,
                           ByteBuffer data)

Compute the HMAC with SHA-256 of data, as defined in http://tools.ietf.org/html/rfc2104#section-2 .

Parameters:

key - The key byte array.

data - The input byte buffer. This does not change the position.

Returns:

The HMAC result.

toHex

public static String toHex(byte[] buffer)

Return a hex string of the contents of buffer.

Parameters:

buffer - The buffer.

Returns:

A string of hex bytes.

base64Encode

public static String base64Encode(byte[] input)

Encode the input as base64 using the appropriate base64Converter_ from establishBase64Converter(), for ANDROID or Java 7+.

Parameters:

input - The bytes to encode.

Returns:

The base64 string.

Throws:

UnsupportedOperationException - If can't establish a base64 converter for this platform.

base64Decode

public static byte[] base64Decode(String encoding)
                           throws SecurityException

Decode the input as base64 using the appropriate base64Converter_ from establishBase64Converter(), for ANDROID or Java 7+.

Parameters:

encoding - The base64 string.

Returns:

The decoded bytes.

Throws:

UnsupportedOperationException - If can't establish a base64 converter for this platform.

SecurityException