Log capturing and event correlation

Problem Statement:
Write a C++/Java program for Log Capturing and Event Correlation.

PROGRAM

mainWindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();

private slots:
    void on_pushButton_3_clicked();

    void on_pushButton_clicked();

    void on_pushButton_2_clicked();

private:
    Ui::MainWindow *ui;
};

#endif // MAINWINDOW_H

******************************************************************
mainWindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "QFile"
#include "QTextStream"
MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::on_pushButton_3_clicked()
{
    QFile file("/var/log/yum.log");
      if (!file.open(QIODevice::ReadOnly | QIODevice::Text))
          return;
   QString line1=" ";
      QTextStream in(&file);
      while (!in.atEnd())  {
          QString line = in.readLine();
          line1.append(line+ "\n");



      }
      ui->textEdit->setText(line1);

}

void MainWindow::on_pushButton_clicked()
{
   ui->textEdit->clear();
    QFile file("/var/log/yum.log");
      if (!file.open(QIODevice::ReadOnly | QIODevice::Text))
          return;
   QString line1=" ";
      QTextStream in(&file);
      while (!in.atEnd())  {
          QString line = in.readLine();
          if(line.count("Updated")!=0)
          {
              line1.append(line+"\n");

          }
      }
      ui->textEdit->setText(line1);

}

void MainWindow::on_pushButton_2_clicked()
{

    ui->textEdit->clear();
     QFile file("/var/log/yum.log");
       if (!file.open(QIODevice::ReadOnly | QIODevice::Text))
           return;
    QString line1=" ";
       QTextStream in(&file);
       while (!in.atEnd())  {
           QString line = in.readLine();
           if(line.count("Installed")!=0)
           {
               line1.append(line+"\n");

           }
       }
       ui->textEdit->setText(line1);

}

OUTPUT