PROJECT Java File Processing Application: Database Application

Objective To type a simple Java program, execute ( run ) the program for some particular values, observe the output and then modify the program.

PROJECT DESCRIPTION

Design an application that uses sequential file processing to query a flat database file.

The initial starter code for your program is given in Figure 1 .

First run and test the starter code, which primarily has file processing objects that declare a file and read data from the file.

After you test the original starter code and verify its functionality, you will then modify the program according to the instructions that follow.

Your completed program ( after modification ) will perform, at the minimum, each of the following tasks

read the data from a comma separated values ( CSV ) text file

use a split(",") function to separate the data into an ArrayList

include a method to locate a consultants name in the ArrayList

include a method to compare numerical data values in the ArrayList

include a method to compare string data values in the ArrayList

Basically, your program is outlined in the given starter code statements shown within Figure 1 , which follows. Review the starter code to understand the mechanisms of the interactions between reading a file and writing to a file. Perform any modifications according to this projects instructions.

Type, compile and run the basic Java program that is shown in Figure 1 , which follows. Then modify the program accordingly.

Information About This Project

In the realm of database processing, a flat file is a text file that holds a table of records.

Here is the data file that is used in this project. The data is converted to comma separated values ( CSV ) to allow easy reading into an array.

Table: Consultants

ID	LName	Fee	Specialty
101	Roberts	3500	Media
102	Peters	2700	Accounting
103	Paul	1600	Media
104	Michael	2300	Web Design
105	Manfred	3500	Broadcasting

Steps to Complete This Project

STEP 1 Open a Java Editor

Open NetBeans or Eclipse and create a Java project with the following details.

For Project Name include: DataApplication

For the Main Class include: DataApplication

In your Code window for this class, shown below, copy the program code shown in Figure 1 below, in the appropriate places, except substitute your own name in place of Sammy Student.

PROJECT Java File Processing Application: Database Application

Figure 1 Source Code for the Database File Processing Program

import java.io.File;

import java.io.FileNotFoundException;

import java.util.ArrayList;

import java.util.Scanner;

// Programmer: Sammy Student

public class DataApplication

{

public static void main(String[] args)

{

try

{

File fin = new File("data.txt");

Scanner scan = new Scanner(fin);

ArrayList theData = new ArrayList();

// read the column headings from the flat text file

String line = scan.nextLine();

while(scan.hasNextLine())

{

line = scan.nextLine();

String[] list = line.split(",");

int key = Integer.parseInt(list[0]);

String name = list[1];

int fee = Integer.parseInt(list[2]);

String specialty = list[3];

theData.add(String.valueOf(key));

theData.add(name);

theData.add(String.valueOf(fee));

theData.add(specialty);

}

int count = 1;

for (int i = 0; i < theData.size(); i++)

{

System.out.print(theData.get(i) + "\t\t");

if(count % 4 == 0 )

System.out.println(" ");

count++;

}

scan.close();

}

catch (FileNotFoundException e)

{

e.printStackTrace();

}

}

}

PROJECT Java File Processing Application: Database Application

STEP 2 Review the Starter Code for this Project

Before you run the initial starter code for this project, which is given in Figure 1 review the program statements that comprise the code. Basically, the starter code assigns a file name to a file reading object. A looping structure is then used to read values from a data file and assign them to an array list. The data will then be analyzed later in this project.

STEP 3 Create and Save a Text Data File

Open a text file within your project folder. Name the text file as: data.txt

Copy the CSV formatted data below into the text file that you just created.

Save the data in the text file.

[ Data File ]

ID,LName,Fee,Specialty

101,Roberts,3500,Media

102,Peters,2700,Accounting

103,Paul,1600,Media

104,Michael,2300,Web Design

105,Manfred,3500,Broadcasting

STEP 4 Build, Compile and Run the Program

From the menu select [ Run ] and click [ Run Project ] to run your app.

Observe the program's output. Notice that the data from the text file is read into an ArrayList and the array list elements are displayed in a console output statement. The data values are displayed in a tabular format.

STEP 5 Modify Your Program

You will now modify your database application by including a method named searchData() that receives the ArrayList elements and allows the program user to search for a name located within the flat file.

If the name of the consultant is located, a message as such is displayed by the search method otherwise a message indicating that the name is not found in the file.

The method for searching names in the flat file is shown below. Place the method in an appropriate location in your program code.

Remember to also write a statement that calls the method.

searchData(theData);

Save your program to update it and perform a trial run of your modified code. Test your program by entering the name of a consultant that appears in the text file and run the program again using a name that is not in the file. Take screen snapshots showing both a data found and data not found example.

PROJECT Java File Processing Application: Database Application

Figure 2 Additional Source Code for the Database File Processing Program

public static void searchData(ArrayList vals)

{

System.out.print("enter a name: ");

Scanner sc = new Scanner(System.in);

String strName = sc.nextLine().trim();

boolean found = false;

for (int i = 0; i < vals.size(); i++)

{

if(vals.get(i).equals(strName.trim()))

{

found = true;

break;

}

}

if(found == true)

System.out.println(" data found ");

else

System.out.println(" data not found ");

sc.close();

}

STEP 6 Test the Program and Write the Data

Now modify your program again by including a new method that will determine if any consultant charges a fee that exceeds $ 2,000 . List all consultants that match this criterion.

Save and test your program.

Finally include another method that will allow the program user to query the flat file and show a count of the consultants that specialize in providing media services.

Save and test your program.

STEP 7 Submit Your Project

Once you have determined that your modified program is correctly displaying the required information, complete the submission process as follows:

Open MS Word and type a heading for a new document that includes your full name, course number, lab number and date.

Within the document paste snapshots of your modified program in action. Label the snapshots of your modified run with a reasonable description.

After your snapshot, paste in your finished source code as well copied in from your Java editor.

Submit the MS Word file to the appropriate course Submittal Box when complete.