uk.ac.ed.epcc.webapp.session

Class RandomService

java.lang.Object

uk.ac.ed.epcc.webapp.session.RandomService

All Implemented Interfaces:

AppContextCleanup, AppContextService<RandomService>

public class RandomService
extends java.lang.Object
implements AppContextService<RandomService>

An AppContextService to generate random tokens and passwords. These need to be secure as they are likely to be used as authentication tokens.

Constructor Summary

Constructors

Constructor and Description
RandomService()

Method Summary

Modifier and Type	Method and Description
void	cleanup() AppContext is being closed.
java.lang.Class	getType() Returns the type of service the class should be registered under.
byte[]	randomBytes(int length)
protected int	randomInt(int total_chars)
java.lang.String	randomString(char[][] chars, int length) Generates random sequences of characters taken from the input range, which has the format:
java.lang.String	randomString(int length) Generates random sequences of characters in the ranges 'a'..'z', 'A'..'Z' and '0'..'9'.

Methods inherited from class java.lang.Object

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

Constructor Detail

RandomService

public RandomService()

Method Detail

cleanup

public void cleanup()

Description copied from interface: AppContextCleanup

AppContext is being closed. Only use this for cleanup that can't be handled by normal garbage collection or for state which is never returned by reference.

Specified by:

cleanup in interface AppContextCleanup

getType

public java.lang.Class getType()

Description copied from interface: AppContextService

Returns the type of service the class should be registered under.

Specified by:

getType in interface AppContextService<RandomService>

Returns:

registration type

randomString

public java.lang.String randomString(char[][] chars,
                                     int length)

Generates random sequences of characters taken from the input range, which has the format:

         {
         ( {<first_char>, <second_char>}, ) | {<single_char>}, ) *
         }
        
 

The second_char value must be higher than the first_char value or the output will be undefined or generate an Exception.

Parameters:

chars - An array containing ranges of characters and/or single characters

length - The length of the desired random string

Returns:

A random string chosen from the provided input

randomInt

protected int randomInt(int total_chars)

Parameters:

total_chars -

Returns:

randomString

public java.lang.String randomString(int length)

Generates random sequences of characters in the ranges 'a'..'z', 'A'..'Z' and '0'..'9'.

Parameters:

length - The desired length of the output String

Returns:

String

randomBytes

public byte[] randomBytes(int length)