randomnum.java

java阿里巴巴代码

/*
*
* 随机数字bean
*/ 

package com.ahbay.mysite;

import java.util.*;
import java.security.SecureRandom;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;


public class RandomNum {

private Long randomnum = null;
private Float randomfloat = null;
private boolean floatvalue = false;
private long upper = 100;
private long lower = 0;
private String algorithm = null;
private String provider = null;
private boolean secure = false;
private Random random = null;
private SecureRandom secrandom = null;

private final float getFloat() {
if (random == null)
return secrandom.nextFloat();
else
return random.nextFloat();
}

public final void generateRandomObject() throws Exception {

// check to see if the object is a SecureRandom object
if (secure) {
try {
// get an instance of a SecureRandom object
if (provider != null)
// search for algorithm in package provider
secrandom = SecureRandom.getInstance(algorithm, provider);
else
secrandom = SecureRandom.getInstance(algorithm);
} catch (NoSuchAlgorithmException ne) {
throw new Exception(ne.getMessage());
} catch (NoSuchProviderException pe) {
throw new Exception(pe.getMessage());
}
} else
random = new Random();
}

/**
* generate the random number
*
*/
private final void generaterandom() {

int tmprandom = 0; // temp storage for random generated number
Integer rand;

// check to see if float value is expected
if (floatvalue)
randomfloat = new Float(getFloat());
else
randomnum = new Long(lower + (long) ((getFloat() * (upper - lower))));
}

public final Number getRandom() {
generaterandom(); 
if (floatvalue)
return randomfloat;
else
return randomnum;
}

public final void setRange(long low, long up) {

// set the upper and lower bound of the range
lower = low;
upper = up;

// check to see if a float value is expected
if ((lower == 0) && (upper == 1))
floatvalue = true;
}

/**
* set the algorithm name
*
* @param value name of the algorithm to use for a SecureRandom object
*
*/
public final void setAlgorithm(String value) {
algorithm = value;
secure = true; // a SecureRandom object is to be used
}

public final void setProvider(String value) 
{
provider = value;
}

public final void setRange(String value) throws Exception 
{
try 
{
upper = new Integer(value.substring(value.indexOf('-') + 1)).longValue();
} catch (Exception ex) {
throw new Exception("upper attribute could not be" +
" turned into an Integer default value was used"); 
}

try 
{
lower = new Integer(value.substring(0, value.indexOf('-'))).longValue();
} catch (Exception ex) {
throw new Exception("lower attribute could not be" +
" turned into an Integer default value was used"); 
}

if ((lower == 0) && (upper == 1))
floatvalue = true;

if (upper < lower)
throw new Exception("You can't have a range where the lowerbound" +
" is higher than the upperbound.");

}


}