/*
* @(#)Main.java
* Author: 88250 <DL88250@gmail.com>, http://blog.csdn.net/DL88250
* Created on May 13, 2008, 4:11:44 PM
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Library General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
package checkthesame;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.List;
import java.util.Random;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
* Check the same record in a file.
* <p>
* Every record in data file is a random serial, like the followings:<br>
* // data file
* 1902323484354370234844<br>
* 1928473090393719374<br>
* ....<br>
* </p>
* @author 88250 <DL88250@gmail.com>, http://blog.csdn.net/DL88250
*/
public class Main {
/**
* store the data records
*/
public static List<String> records = new ArrayList<String>();
/**
* statistics
*/
public static List<List<String>> statistics = new ArrayList<List<String>>();
/**
* Read the records from the data file which named "data.txt" into memory,
* using a <code>java.util.ArrayList</code> store them.
* @see #records
*/
public static void readRecords() {
System.out.println("Get starting read records....");
try {
BufferedReader reader = new BufferedReader(
new FileReader("data.txt"));
String aLine;
while ((aLine = reader.readLine()) != null) {
records.add(aLine);
}
reader.close();
} catch (IOException ex) {
Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
}
System.out.println("The amount of records: " + records.size());
}
/**
* Create some records for test.
*/
public static void createTestRecords() {
File file = new File("data.txt");
if (file.exists()) {
file.delete();
}
try {
BufferedWriter writer =
new BufferedWriter(new FileWriter("data.txt"));
Random random = new Random();
byte[] bytes = new byte[16];
for (int i = 0; i < 1000000; i++) {
StringBuffer aLine;
random.nextBytes(bytes);
aLine = new StringBuffer();
for (int j = 0; j < 16; j++) {
aLine.append((int) bytes[j]);
}
// System.out.println(aLine);
writer.write(aLine.toString());
//System.out.println();
writer.newLine();
}
writer.close();
} catch (IOException ex) {
Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
}
}
/**
* Main program entry.
* @param args the command line arguments, should be <code>null</code>
*/
public static void main(String[] args) {
createTestRecords();
readRecords();
displayRecords(10);
checkTheSame();
}
/**
* Check the same data records in {@link #records}.
*/
public static void checkTheSame() {
sortTheRecords(); // sort them
// displayRecords(10);
for (int i = 0; i < records.size() - 1; i++) {
String record1 = records.get(i);
String record2 = records.get(i + 1);
if (record1.equals(record2)) {
List<String> equalities = new ArrayList<String>();
equalities.add(record1);
equalities.add(record2);
statistics.add(equalities);
}
}
displayStats();
}
/**
* Display the data records in console.
* @param amount display amount, start from {@link #records}'s beginning
*/
public static void displayRecords(int amount) {
if (amount < 0 || amount > records.size()) {
System.out.println("The specified amount exceeds the Data records" +
"size!");
}
System.out.println("Display: ");
for (int i = 0; i < amount; i++) {
System.out.println(records.get(i));
}
System.out.println();
}
/**
* Display the statistic results in console.
*/
private static void displayStats() {
System.out.println("Statistics: ");
System.out.println("A amount of the same data records: " + statistics.
size());
for (List<String> aEqualities : statistics) {
System.out.println(aEqualities.get(0) + " occurs " + aEqualities.
size());
}
}
/**
* Using {@link java.util.Collections#sort(java.util.List)} to sort the
* data records.
*/
@SuppressWarnings("unchecked")
private static void sortTheRecords() {
java.util.Collections.sort(records,
new Comparator() {
@Override
public int compare(Object o1,
Object o2) {
String r1 =
(String) o1;
String r2 =
(String) o2;
return r1.compareTo(r2);
}
});
}
}