datagenerator

package xyz.dengchao.cooooool;


import java.io.File;
import java.io.FileNotFoundException;
import java.io.PrintWriter;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.Random;


public class DataGenerator {
static Random rand = new Random();


public static void main(String[] args) throws Exception {


long time = System.currentTimeMillis();
int rows = 1000 * 1000;
File file = new File("input.csv");
try (PrintWriter out = new PrintWriter(file);) {
out.println("Facility ID(Integer/SORT ASC),Product Type(String/SORT ASC),Host ID(Integer/SORT ASC),Maturity(Date/SORT ASC),Exposure(Double/SORT ASC)");
new DataGenerator(
//
 new IntGenerator(10000, 50000, 100)// FacilityID
, new StringGenerator(10, 100)// ProductyType
, new IntGenerator(100, 1000, 100)// Host ID
, new DateGenerator("01/01/2000", "12/31/2020", 100)// Maturity
, new DoubleGenerator(0, 5000000, rows)// Exposure
//
).generate(rows, out);
time = System.currentTimeMillis() - time;
System.out.println("time " + time);
}
}


ColumnGenerator[] generators;


public DataGenerator(ColumnGenerator... generators) {
super();
this.generators = generators;
}


void generate(int rows, PrintWriter out) throws FileNotFoundException {
for (int i = 0; i < rows; i++) {
if (i % 1000000 == 0) {
System.out.println(i);
}
int length = generators.length;
for (int j = 0; j < length; j++) {
ColumnGenerator g = generators[j];
out.print(g.gen());
if (j < length - 1) {
out.print(",");
} else {
out.println();
}
}
}
}
}


interface ColumnGenerator {
String gen();
}


class IntGenerator implements ColumnGenerator {
int min;
int max;
int total;
Random rand = new Random();
int scope;


public IntGenerator(int min, int max, int total) {
super();
this.min = min;
this.max = max;
this.total = total;
scope = max - min;
}


@Override
public String gen() {
return Integer.toString((min + rand.nextInt(total) * scope / total));
}


}


class DoubleGenerator implements ColumnGenerator {
double min;
double max;
double scope;
int total;
Random rand = new Random();


public DoubleGenerator(double min, double max, int total) {
super();
this.min = min;
this.max = max;
this.total = total;
scope = max - min;
}


@Override
public String gen() {
return "" + (min + rand.nextDouble() * scope);
}
}


class DateGenerator implements ColumnGenerator {
long min;
long max;
long scope;
int total;


Random rand = new Random();
SimpleDateFormat df = new SimpleDateFormat("MM/dd/yyyy");


public DateGenerator(String min, String max, int total)
throws ParseException {
super();
this.min = df.parse(min).getTime();
this.max = df.parse(max).getTime();
this.total = total;
scope = this.max - this.min;
}


@Override
public String gen() {
return df.format(new Date((min + rand.nextInt(total) * scope / total)));
}
}


class StringGenerator implements ColumnGenerator {
private static final String CHARS = " abcdef ghijklmn opqrst uvwxyz ABCDEFG HIJKLMN OPQRST UVWXYZ 01234 56789 ";
int len;
int total;


Random rand = new Random();
List<String> list = new ArrayList<String>();


public StringGenerator(int len, int total) {
super();
this.len = len;
this.total = total;
for (int i = 0; i < total; i++) {
list.add(randString(len));
}
}


char[] chars = CHARS.toCharArray();


String randString(int len) {
char[] chars = this.chars;
int clen = chars.length;
char[] str = new char[len];
for (int i = 0; i < len; i++) {
str[i] = chars[rand.nextInt(clen)];
}
return new String(str);
}


@Override
public String gen() {
return list.get(rand.nextInt(list.size()));
}


}