Question

DatabaseFilter Design a DatabaseFilter class that will manage the file 1/O (input/output) of an employee ArrayList object. For a Database Filter class to actually store an ArrayList object, it must know the file to which the list must be read from or written to. Note: It is expected that you may have more methods within your class design than requested in the specifications described below. However, your class should support at a minimum the following data and operations: encapsulated data fields: O i. data: reference to the array list object that will store the data from the database file. o constructor: i. a default constructor that two empty array list objects for data. o methods: At a minimum the following methods should be included in this class: filterover 40: filters the data for employees over 40 and writes it to the indicated file location. i. public void filterover40 (String 1location) throws FileNotFoundException ii. filterUnder40: filters the data for employees under 40 and writes it to the indicated file location. public void filterUnder40 (String location) throws FileNot FoundException filterSalary: filters the data for employees who make under 55,000 in salary and writes it to the indicated file location. ii. public void filterSalary (String location) throws FileNot FoundException filterService: writes a file of employees who have been working at the college for 20 years or more. iv. public void filterService (String location) throws FileNot FoundException

Answer 1

//================ Main.java ================
//Tester class

import java.io.BufferedReader;
import java.io.File;

import java.io.FileReader;

public class Main
{
   DatabaseFilter filter;
   Main()
   {
       filter = new DatabaseFilter();
      
   }
   public void filterOver40Tester(String location)
   {
       try
       {
           System.out.println("\n**************** Filter Over 40 Tester ***************\n");
           filter.filterOver40(location);
           displayData(location);
           System.out.println("\n**************** END of Test ***************\n");
       }
       catch(Exception e)
       {
           System.out.println("\n------------------ Exception at filterOver40Tester ----------------------\n");
           System.out.println(e.getMessage());
           System.out.println("\n------------------ End Of Exception ----------------------");
       }
   }
  
   public void filterUnder40Tester(String location)
   {
       try
       {
           System.out.println("\n**************** Filter Under 40 Tester ***************\n");
           filter.filterUnder40(location);
           displayData(location);
           System.out.println("\n**************** END of Test ***************\n");
       }
       catch(Exception e)
       {
           System.out.println("\n------------------ Exception at filterUnder40Tester ----------------------\n");
           System.out.println(e.getMessage());
           System.out.println("\n------------------ End Of Exception ----------------------");
       }
   }
  
   public void filterSalaryTester(String location)
   {
       try
       {
           System.out.println("\n**************** Filter Salary Tester ***************\n");
           filter.filterSalary(location);
           displayData(location);
           System.out.println("\n**************** END of Test ***************\n");
       }
       catch(Exception e)
       {
           System.out.println("\n------------------ Exception at filterSalaryTester ----------------------\n");
           System.out.println(e.getMessage());
           System.out.println("\n------------------ End Of Exception ----------------------");
       }
   }
  
   public void filterService(String location)
   {
       try
       {
           System.out.println("\n**************** Filter Service Tester ***************\n");
           filter.filterService(location);
           displayData(location);
           System.out.println("\n**************** END of Test ***************\n");
       }
       catch(Exception e)
       {
           System.out.println("\n------------------ Exception at filterService ----------------------\n");
           System.out.println(e.getMessage());
           System.out.println("\n------------------ End Of Exception ----------------------");
       }
   }
  
   public void readTester(String location)
   {
       try
       {
           System.out.println("\n**************** Reader Tester ***************\n");
           filter.read(location);
           filter.printEmployees();
           System.out.println("\n**************** END of Test ***************\n");
       }
       catch(Exception e)
       {
           System.out.println("\n------------------ Exception at readTester ----------------------\n");
           System.out.println(e.getMessage());
           System.out.println("\n------------------ End Of Exception ----------------------");
       }
   }
  
   public void searchTester(String name)
   {
       try
       {
           System.out.println("\n**************** Search Tester ***************\n");
           filter.search(name);
          
           System.out.println("\n**************** END of Test ***************\n");
       }
       catch(Exception e)
       {
           System.out.println("\n------------------ Exception at searchTester ----------------------\n");
           System.out.println(e.getMessage());
           System.out.println("\n------------------ End Of Exception ----------------------");
       }
   }
  
   public void writeTester(String location)
   {
       try
       {
           System.out.println("\n**************** Writer Tester ***************\n");
           filter.write(location);
           displayData(location);
           System.out.println("\n**************** END of Test ***************\n");
       }
       catch(Exception e)
       {
           System.out.println("\n------------------ Exception at writeTester ----------------------\n");
           System.out.println(e.getMessage());
           System.out.println("\n------------------ End Of Exception ----------------------");
       }
   }
  
   public void writeCSTester(String location)
   {
       try
       {
           System.out.println("\n**************** WriterCS Tester ***************\n");
           filter.writeCS(location);
           displayData(location);
           System.out.println("\n**************** END of Test ***************\n");
       }
       catch(Exception e)
       {
           System.out.println("\n------------------ Exception at writeCSTester ----------------------\n");
           System.out.println(e.getMessage());
           System.out.println("\n------------------ End Of Exception ----------------------");
       }
   }
  
   public void sortAlphabeticalOrderTester(String location)
   {
       try
       {
           System.out.println("\n**************** Sort Alphabetical Order Tester ***************\n");
           filter.sortAlphabeticalOrder(location);
           displayData(location);
           System.out.println("\n**************** END of Test ***************\n");
       }
       catch(Exception e)
       {
           System.out.println("\n------------------ Exception at sortAlphabeticalOrderTester ----------------------\n");
           System.out.println(e.getMessage());
           System.out.println("\n------------------ End Of Exception ----------------------");
       }
   }
  
   public void displayData(String location)
   {
       File f = new File(location);
       System.out.println("\nDisplaying Data in : "+location+"\n");
       if(f.canRead() == false)
       {
           System.err.println("Unable to perform Read in File: "+location);
           return;
       }
      
       try
       {
           BufferedReader reader = new BufferedReader(new FileReader(f));
           String line = reader.readLine();
           while(line != null)
           {
               try
               {
                   Employee emp = filter.parse(line);
                   System.out.println(emp);
               }
               catch(Exception e)
               {
                  
                   System.err.println("Exception occured while reading Line: "+line);
                   System.out.println("Exception Details: "+e.getMessage());
                  
               }
               line = reader.readLine();
           }
           reader.close();
       }
       catch(Exception e)
       {
          
           System.err.println("Exception Occured while reading the File: "+location);
           System.err.println("Details about exception: "+e.getMessage());
          
       }
   }
   public static void main(String[] args)
   {
      
       //you have to pass absolute path to the functions as locations.
       //or else you will get FileNotFoundException.
       //all the files are in current working directory.
       //so i get current path using absolute path from java.nio.file.Paths
       Main tester = new Main();
      
       tester.readTester("emp.txt");
       tester.filterOver40Tester("filterOver40.txt");
       tester.filterUnder40Tester("filterUnder40.txt");
       tester.filterSalaryTester("filterSalary.txt");
       tester.filterService("filterService.txt");
       tester.writeTester("writedEmps.txt");
       tester.writeCSTester("writeCSEmps.txt");
       tester.sortAlphabeticalOrderTester("sortedEmps.txt");
       tester.searchTester("John Wick");
      

   }

}

//================ Employee.java ================

public class Employee
{
   private String name;
   private int age;
   private String office;
   private double salary;
   private double priority;
   public Employee(String n,int a, String off,double sal,double pri)
   {
       name = n;
       age = a;
       office = off;
       salary = sal;
       priority = pri;
   }
   public String getName() {
       return name;
   }
   public int getAge() {
       return age;
   }
   public String getOffice() {
       return office;
   }
   public double getSalary() {
       return salary;
   }
   public double getPriority() {
       return priority;
   }
   public String toString()
   {
       return name+ "," +age+ "," +office+ "," +salary+ "," +priority+"\n";
   }
}

//================ DatabaseFilter.java ================

import java.util.*;
import java.io.*;
public class DatabaseFilter
{
   private ArrayList<Employee> data;
   public DatabaseFilter()
   {
       data = new ArrayList<Employee>();
   }
  
   public void filterOver40(String location) throws FileNotFoundException
   {
       File f = new File(location);
       if(f.exists() == false)
       {
           throw new FileNotFoundException("File: "+location+" is Not Found");
       }
       if(f.canWrite() == false)
       {
           System.err.println("Unable to perform Write in File: "+location);
           return;
       }
       BufferedWriter writer = null;
       try
       {
           writer = new BufferedWriter(new FileWriter(f));
           for(int i =0;i<data.size();i++)
           {
               Employee emp = data.get(i);
               if(emp.getAge() >=40 )
               {
                   writer.write(""+emp);
               }
           }
           writer.close();
       }
       catch(Exception e)
       {
           System.err.println("Exception Occured while writing into File: "+location);
           System.err.println("Details about exception: "+e.getMessage());
          
       }
      
      
      
   }
  
   public void filterUnder40(String location) throws FileNotFoundException
   {
       File f = new File(location);
       if(f.exists() == false)
       {
           throw new FileNotFoundException("File: "+location+" is Not Found");
       }
       if(f.canWrite() == false)
       {
           System.err.println("Unable to perform Write in File: "+location);
           return;
       }
      
       try
       {
           BufferedWriter writer = new BufferedWriter(new FileWriter(f));
           for(int i =0;i<data.size();i++)
           {
               Employee emp = data.get(i);
               if(emp.getAge() < 40 )
               {
                   writer.write(""+emp);
               }
           }
           writer.close();
       }
       catch(Exception e)
       {
           System.err.println("Exception Occured while writing into File: "+location);
           System.err.println("Details about exception: "+e.getMessage());
       }
      
      
   }
   //method that writes the employee with salary under 55000 into the
   //given location
   public void filterSalary(String location) throws FileNotFoundException
   {
       File f = new File(location);
       if(f.exists() == false)
       {
           throw new FileNotFoundException("File: "+location+" is Not Found");
       }
       if(f.canWrite() == false)
       {
           System.err.println("Unable to perform Write in File: "+location);
           return;
       }
      
       try
       {
           BufferedWriter writer = new BufferedWriter(new FileWriter(f));
           for(int i =0;i<data.size();i++)
           {
               Employee emp = data.get(i);
               if(emp.getSalary() <= 55000 )
               {
                   writer.write(""+emp);
               }
           }
           writer.close();
       }
       catch(Exception e)
       {
           System.err.println("Exception Occured while writing into File: "+location);
           System.err.println("Details about exception: "+e.getMessage());
       }
      
      
   }
   //Method that takes a location and writes the employees
   //whose service is >= 20 years.
   //i have taken priority as the number of years worked(service) of an employee.
   //if the priority of an employee is >=20 then he/she will be written into
   //the file with the given location.
   public void filterService(String location) throws FileNotFoundException
   {
       File f = new File(location);
       if(f.exists() == false)
       {
           throw new FileNotFoundException("File: "+location+" is Not Found");
       }
       if(f.canWrite() == false)
       {
           System.err.println("Unable to perform Write in File: "+location);
           return;
       }
      
       try
       {
           BufferedWriter writer = new BufferedWriter(new FileWriter(f));
           for(int i =0;i<data.size();i++)
           {
               Employee emp = data.get(i);
               if(emp.getPriority() >= 20 )
               {
                   writer.write(""+emp);
               }
           }
           writer.close();
       }
       catch(Exception e)
       {
          
           System.err.println("Exception Occured while writing into File: "+location);
           System.err.println("Details about exception: "+e.getMessage());
          
       }
      
      
   }
   public Employee parse(String line) throws NumberFormatException,IllegalFormatException
   {
       String info[] = line.trim().split(",");
       String name = info[0];
       int age = Integer.parseInt(info[1]);
       String office = info[2];
       double salary = Double.parseDouble(info[3]);
       double priority = Double.parseDouble(info[4]);
       return new Employee(name,age,office,salary,priority);
      
   }
  
   public void read(String location) throws FileNotFoundException
   {
       File f = new File(location);
       if(f.exists() == false)
       {
           throw new FileNotFoundException("File: "+location+" is Not Found");
       }
       if(f.canRead() == false)
       {
           System.err.println("Unable to perform Read in File: "+location);
           return;
       }
      
       try
       {
           BufferedReader reader = new BufferedReader(new FileReader(f));
           String line = reader.readLine();
           while(line != null)
           {
               try
               {
                   Employee emp = parse(line);
                   data.add(emp);
               }
               catch(Exception e)
               {
                  
                   System.err.println("Exception occured while reading Line: "+line);
                   System.out.println("Exception Details: "+e.getMessage());
                  
               }
               line = reader.readLine();
           }
           reader.close();
       }
       catch(Exception e)
       {
          
           System.err.println("Exception Occured while reading the File: "+location);
           System.err.println("Details about exception: "+e.getMessage());
          
       }
   }
   //i think there is a mistake in the function prototype mentioned for search method.
   //throws FileNotFoundException is used but the String location parameter is not given.
   //so assume that it meant to search for name of employee in arraylist of employees.
   //which don't need FileNotFoundException
   //if you think it is not what you required please comment about what you need.
   //i will modify it.
   public void search(String name)
   {
       boolean found = false;
       int ind = -1;
       for(int i =0;i<data.size();i++)
       {
           if(data.get(i).getName().equals(name))
           {
               found = true;
               ind = i;
           }
       }
       if(found)
       {
           System.out.println("\nEmployee with name: "+name+ " is found at index: "+ind);
           System.out.println("Employee Details: ");
           printEmployeeProperty(data.get(ind));
       }
       else
       {
          
           System.out.println("\nEmployee with name: "+name+ " is Not found in Database");
       }
   }
  
   public void sortAlphabeticalOrder(String location) throws FileNotFoundException
   {
       sortEmployees();
       try
       {
           write(location);
       }
       catch(FileNotFoundException e)
       {
           throw new FileNotFoundException("File: "+location+" is Not Found");
       }
      
   }
   public void sortEmployees()
   {
       Collections.sort(data,new EmployeeComparator());
   }
  
   public void write(String location)throws FileNotFoundException
   {
       File f = new File(location);
       if(f.exists() == false)
       {
           throw new FileNotFoundException("File: "+location+" is Not Found");
       }
       if(f.canWrite() == false)
       {
           System.err.println("Unable to perform Write in File: "+location);
           return;
       }
      
       try
       {
           BufferedWriter writer = new BufferedWriter(new FileWriter(f));
           for(int i =0;i<data.size();i++)
           {
               writer.write(""+data.get(i));
           }
           writer.close();
       }
       catch(Exception e)
       {
          
           System.err.println("Exception Occured while writing into File: "+location);
           System.err.println("Details about exception: "+e.getMessage());
          
       }
   }
  
   public void writeCS(String location)throws FileNotFoundException
   {
       File f = new File(location);
       if(f.exists() == false)
       {
           throw new FileNotFoundException("File: "+location+" is Not Found");
       }
       if(f.canWrite() == false)
       {
           System.err.println("Unable to perform Write in File: "+location);
           return;
       }
      
       try
       {
           BufferedWriter writer = new BufferedWriter(new FileWriter(f));
           for(int i =0;i<data.size();i++)
           {
               Employee emp = data.get(i);
               //write comma separated data to file.
               writer.write(emp.getName() + "," + emp.getAge() + "," + emp.getOffice() + "," + emp.getSalary() + "," + emp.getPriority()+"\n");
           }
           writer.close();
       }
       catch(Exception e)
       {
          
           System.err.println("Exception Occured while writing into File: "+location);
           System.err.println("Details about exception: "+e.getMessage());
          
       }
   }
   public void printEmployeeProperty(Employee emp)
   {
       System.out.println("\n\tName: " + emp.getName());
       System.out.println("\tAge: " + emp.getAge());
       System.out.println("\tOffice: " + emp.getOffice());
       System.out.println("\tSalary: " + emp.getSalary());
       System.out.println("\tPriority: " + emp.getPriority());
   }
   public void printEmployees()
   {
       System.out.println("\n----------------- Employees --------------\n");
       for(int i = 0;i<data.size();i++)
       {
           Employee emp = data.get(i);
           printEmployeeProperty(emp);
       }
   }
}

//================ EmployeeComparator.java ================

import java.util.Comparator;
public class EmployeeComparator implements Comparator<Employee>
{
   @Override
   public int compare(Employee one,Employee two)
   {
       //splitting the name to get first name and last name of the employees
       //at 0th index there will be first name
       //at index 1 there will be last name.
       String oneName[] = one.getName().split(" ");
       String twoName[] = two.getName().split(" ");

       //comparing last names for sorting
       int lastNameRes = oneName[1].compareTo(twoName[1]);
       //if last name result is not 0 then return value.
       //last name of first emp is having higher precedence
       if(lastNameRes != 0)
       {
           return lastNameRes;
       }
      
       //comparing first names.
       int firstNameRes = oneName[0].compareTo(twoName[0]);
       //return the result of first names.
       return firstNameRes;
      
   }
}

//====================== Output ====================
**************** Reader Tester ***************

----------------- Employees --------------

   Name: John Smith
   Age: 30
   Office: Development
   Salary: 39000.0
   Priority: 10.0

   Name: Tony Stark
   Age: 44
   Office: Mechanic
   Salary: 56000.0
   Priority: 30.0

   Name: Steve Rogers
   Age: 80
   Office: Technician
   Salary: 32000.0
   Priority: 29.0

   Name: Barry Allen
   Age: 25
   Office: Ground Team
   Salary: 30000.0
   Priority: 15.0

   Name: Sam Watson
   Age: 30
   Office: Ground Team
   Salary: 25000.0
   Priority: 19.0

   Name: John Wick
   Age: 40
   Office: Ground Team
   Salary: 60000.0
   Priority: 40.0

**************** END of Test ***************

**************** Filter Over 40 Tester ***************

Displaying Data in : filterOver40.txt

Tony Stark,44,Mechanic,56000.0,30.0

Steve Rogers,80,Technician,32000.0,29.0

John Wick,40,Ground Team,60000.0,40.0

**************** END of Test ***************

**************** Filter Under 40 Tester ***************

Displaying Data in : filterUnder40.txt

John Smith,30,Development,39000.0,10.0

Barry Allen,25,Ground Team,30000.0,15.0

Sam Watson,30,Ground Team,25000.0,19.0

**************** END of Test ***************

**************** Filter Salary Tester ***************

Displaying Data in : filterSalary.txt

John Smith,30,Development,39000.0,10.0

Steve Rogers,80,Technician,32000.0,29.0

Barry Allen,25,Ground Team,30000.0,15.0

Sam Watson,30,Ground Team,25000.0,19.0

**************** END of Test ***************

**************** Filter Service Tester ***************

Displaying Data in : filterService.txt

Tony Stark,44,Mechanic,56000.0,30.0

Steve Rogers,80,Technician,32000.0,29.0

John Wick,40,Ground Team,60000.0,40.0

**************** END of Test ***************

**************** Writer Tester ***************

Displaying Data in : writedEmps.txt

John Smith,30,Development,39000.0,10.0

Tony Stark,44,Mechanic,56000.0,30.0

Steve Rogers,80,Technician,32000.0,29.0

Barry Allen,25,Ground Team,30000.0,15.0

Sam Watson,30,Ground Team,25000.0,19.0

John Wick,40,Ground Team,60000.0,40.0

**************** END of Test ***************

**************** WriterCS Tester ***************

Displaying Data in : writeCSEmps.txt

John Smith,30,Development,39000.0,10.0

Tony Stark,44,Mechanic,56000.0,30.0

Steve Rogers,80,Technician,32000.0,29.0

Barry Allen,25,Ground Team,30000.0,15.0

Sam Watson,30,Ground Team,25000.0,19.0

John Wick,40,Ground Team,60000.0,40.0

**************** END of Test ***************

**************** Sort Alphabetical Order Tester ***************

Displaying Data in : sortedEmps.txt

Barry Allen,25,Ground Team,30000.0,15.0

Steve Rogers,80,Technician,32000.0,29.0

John Smith,30,Development,39000.0,10.0

Tony Stark,44,Mechanic,56000.0,30.0

Sam Watson,30,Ground Team,25000.0,19.0

John Wick,40,Ground Team,60000.0,40.0

**************** END of Test ***************

**************** Search Tester ***************

Employee with name: John Wick is found at index: 5
Employee Details:

   Name: John Wick
   Age: 40
   Office: Ground Team
   Salary: 60000.0
   Priority: 40.0

**************** END of Test ***************