Class AlternatingCoin

java.lang.Object
  AlternatingCoin

All Implemented Interfaces:

RandomWithParity

public class AlternatingCoin
extends java.lang.Object
implements RandomWithParity

Generates a binary coin (0 or 1) in strict alternating sequence. With every flip of the coin, the coin changes from 0 to 1 or vice versa. The first call returns a 0, then 1, then 0, and so on.

Correspondence (abstraction relation):

|history| is even <==> doneEvenFlips

Author:

paolo

Field Summary

private boolean

doneEvenFlips True if and only if an even number of invocations to this AlternatingCoin have been made.

Constructor Summary

AlternatingCoin()
Initialially, zero flips have been performed, hence doneEvenFlips is true.

Method Summary

int	generateNumber(int upperBound) Returns a 0 or a 1 (alternating) and ignoring upperBound parameter.

Methods inherited from class java.lang.Object

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

Field Detail

doneEvenFlips

private boolean doneEvenFlips

True if and only if an even number of invocations to this AlternatingCoin have been made.

Constructor Detail

AlternatingCoin

public AlternatingCoin()

Initialially, zero flips have been performed, hence doneEvenFlips is true.

Method Detail

generateNumber

public int generateNumber(int upperBound)

Returns a 0 or a 1 (alternating) and ignoring upperBound parameter. The first number returned is 0.

Specified by:

generateNumber in interface RandomWithParity

Parameters:

upperBound - the maximum value that can be generated by this call

Returns:

0 <= generateNumber <= upperBound

See Also:

RandomWithParity.generateNumber(int)