MyEclipse_key_algorithm

package com.test.java.util.lang;

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStreamReader;

class MyEclipseGen
{

	private static final String LL = "Decompiling this copyrighted software is a violation of both your license agreement and the Digital Millenium Copyright Act of 1998 (http://www.loc.gov/copyright/legislation/dmca.pdf). Under section 1204 of the DMCA, penalties range up to a $500,000 fine or up to five years imprisonment for a first offense. Think about it; pay for a license, avoid prosecution, and feel better about yourself.";

	public String getSerial(String userId, String licenseNum)
	{

		java.util.Calendar cal = java.util.Calendar.getInstance();

		cal.add(1, 3);

		cal.add(6, -1);

		java.text.NumberFormat nf = new java.text.DecimalFormat("000");

		licenseNum = nf.format(Integer.valueOf(licenseNum));

		String verTime = new StringBuilder("-").append(

		new java.text.SimpleDateFormat("yyMMdd").format(cal.getTime()))

		.append("0").toString();

		String type = "YE3MP-";

		String need = new StringBuilder(userId.substring(0, 1)).append(type)

		.append("300").append(licenseNum).append(verTime).toString();

		String dx = new StringBuilder(need).append(LL).append(userId)

		.toString();

		int suf = this.decode(dx);

		String code = new StringBuilder(need).append(String.valueOf(suf))

		.toString();

		return this.change(code);

	}

	private int decode(String s)
	{

		int i;

		char[] ac;

		int j;

		int k;

		i = 0;

		ac = s.toCharArray();

		j = 0;

		k = ac.length;

		while (j < k)
		{

			i = (31 * i) + ac[j];

			j++;

		}

		return Math.abs(i);

	}

	private String change(String s)
	{

		byte[] abyte0;

		char[] ac;

		int i;

		int k;

		int j;

		abyte0 = s.getBytes();

		ac = new char[s.length()];

		i = 0;

		k = abyte0.length;

		while (i < k)
		{

			j = abyte0[i];

			if ((j >= 48) && (j <= 57))
			{

				j = (((j - 48) + 5) % 10) + 48;

			}
			else if ((j >= 65) && (j <= 90))
			{

				j = (((j - 65) + 13) % 26) + 65;

			}
			else if ((j >= 97) && (j <= 122))
			{

				j = (((j - 97) + 13) % 26) + 97;

			}

			ac[i] = (char) j;

			i++;

		}

		return String.valueOf(ac);

	}

	public MyEclipseGen()
	{

		super();

	}

	public static void main(String[] args)
	{

		try
		{

			System.out.println("please input register name:");

			BufferedReader reader = new BufferedReader(new InputStreamReader(

			System.in));

			String userId = null;

			userId = reader.readLine();

			MyEclipseGen myeclipsegen = new MyEclipseGen();

			String res = myeclipsegen.getSerial(userId, "5");

			System.out.println("Serial:" + res);

			reader.readLine();

		}
		catch (IOException ex)
		{

		}

	}

}