1. APPLICATION TO DOCUMENT ALL THE
NECESSARY DETAILS OF JAVA CLASSES
OF A PROJECT AT ONCE INTO AN EXCEL
FILE
I hope ,you all have liked my earlier contribution ”MICROSOFT OUTLOOK CHECKER”. Now coming to
this one, let’s have a look on the following
Problem Definition:
 When I joined a new project, I saw that my teammates have almost completed the coding work.
It was the time for testing and documentation.
 Then I came to know that this documentation work required ample amount of time . No matter
how much you are skilled, you need to go through each and every java class of a project and
then need to find all the methods, their return types, all the variables used, their data types. All
this constitutes a hectic and time consuming work.
Solution Details:
To resolve all these problems, I have developed a JAVA PROGRAM that can document all the details
of java classes (i.e. class name , class methods and their return type, class variables and their data
type)of all the packages of a project at once into an excel file.
When you run this program, a single excel file is created in the same folder(package which stores this
java program) , with multiple worksheets and each sheet represents the single class and holds the name
of its class itself. This worksheet comprises of all the above mentioned details of a class.
On a single click, you can get the details of all the files at once. I hope that it will ease the task of
documentation and will save your precious time too.

2. My Sample Package includes:
Jar files :
 dom4j-1.6.1.jar
 poi-3.9-20121203.jar
 poi-ooxml-3.9-20121203.jar
 poi-ooxml-schemas-3.9-20121203.jar
 stax-api-1.0.1.jar
 xmlbeans-2.3.0.jar
Java programs:
 PlaceEncoder.java
 FoodEncoder.java
 MainProgram.java
The files which hold the details are
1. PlaceEncoder.java
2. FoodEncoder.java
The MainProgram.java contains the main code to fetch all the details from both files and it creates an
excel file “DetailsOfTheClassses.xlsx”

3. PlaceEncoder.java
package projectstests;
public class PlaceEncoder {
private String paris;
private int pariscode;
private float flightCharges;
public static void main(String[] args) {
}
public float getFlightCharges() {
return flightCharges;
}
public String getParis() {
return paris;
}
public int getPariscode() {
return pariscode;
}
public void setFlightCharges(float f) {
flightCharges = f;
}
public void setParis(String string) {
paris = string;
}
public void setPariscode(int i) {
pariscode = i;
}
}

4. FoodEncoder.java
package projectstests;
public class FoodEncoder {
private String biryani;
private String shahiPanir;
private int menuCode;
public static void main(String[] args) {
}
public String getBiryani() {
return biryani;
}
public int getMenuCode() {
return menuCode;
}
public String getShahiPanir() {
return shahiPanir;
}
public void setBiryani(String string) {
biryani = string;
}
public void setMenuCode(int i) {
menuCode = i;
}
public void setShahiPanir(String string) {
shahiPanir = string;
}
}

5. MainProgram.java
package projectstests;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.openxml4j.exceptions.InvalidFormatException;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
public class MainProgram {
/**
* @param args
* @throws IOException
* @throws InvalidFormatException
*/
private static void replace(Class secretClass, HSSFWorkbook workbook,
FileOutputStream out) throws InvalidFormatException, IOException {
// TODO Auto-generated method stub
// Obtaining the class name
String fileName = secretClass.getName();
// Assigning the class name to the worksheet
HSSFSheet sheet = workbook.createSheet(fileName);
// This data needs to be written (Object[])
Map<String, Object[]> data = new TreeMap<String, Object[]>();
data.put("1", new Object[] { "", "VARIABLE NAME", "DATA TYPE", "",
"METHOD NAME", "RETURN TYPE" });
// Obtaining all the details of the class
Method methods[] = secretClass.getDeclaredMethods();
Field fields[] = secretClass.getDeclaredFields();
int noOfFields = fields.length;
int noOfMethods = methods.length;
if (noOfMethods >= noOfFields) {
for (int i = 0; i < methods.length; i++)
{

6. String returntypes = methods[i].getReturnType().toString();
methods[i].setAccessible(true);
if ((noOfFields > 0)) {
fields[i].setAccessible(true);
String varReturntypes = fields[i].getType().toString();
data.put(String.valueOf(i + 2),
new Object[] { "", fields[i].getName(),
varReturntypes, "", methods[i].getName(),
returntypes });
} else {
data.put(String.valueOf(i + 2), new Object[] { "", "", "",
"", methods[i].getName(), returntypes });
}
noOfFields--;
}
}
else {
for (int i = 0; i < fields.length; i++) {
String varReturntypes = fields[i].getType().toString();
fields[i].setAccessible(true);
if (noOfMethods > 0) {
methods[i].setAccessible(true);
String returntypes = methods[i].getReturnType().toString();
data.put(String.valueOf(i + 2),
new Object[] { "", fields[i].getName(),
varReturntypes, "", methods[i].getName(),
returntypes });
} else {
data.put(String.valueOf(i + 2), new Object[] { "",
fields[i].getName(), varReturntypes, "", "", "" });
}
noOfMethods--;
}
}
// Iterate over data and write to sheet
Set<String> keyset = data.keySet();
int rownum = 0;
for (String key : keyset) {
Row row = sheet.createRow(rownum++);
Object[] objArr = data.get(key);
int cellnum = 0;

7. for (Object obj : objArr) {
Cell cell = row.createCell(cellnum++);
if (obj instanceof String)
cell.setCellValue((String) obj);
else if (obj instanceof Integer)
cell.setCellValue((Integer) obj);
}
}
}
public static void main(String[] args)
{
try {
MainProgram mainProgram = new MainProgram();
// Creating the xls file with worksheet
FileOutputStream out = new FileOutputStream(new File(
"DetailsOfTheClassses.xls"));
HSSFWorkbook workbook = new HSSFWorkbook();
// Classname is PlaceEncoder
PlaceEncoderinstance = new PlaceEncoder ();
Class secretClass = instance.getClass();
mainProgram.replace(secretClass, workbook, out);
// Classname is FoodEncoder
FoodEncoderinstance1 = new FoodEncoder ();
secretClass = instance1.getClass();
mainProgram.replace(secretClass, workbook, out);
workbook.write(out);
out.close();
System.out
.println("DetailsOfTheClassses.xls written successfully on disk.");
} catch (InvalidFormatException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}

8. Explanation of MainProgram.java
 To access an excel file, Apache POI provides certain easy-to-use APIs.
 I have used HSSFWorkbook and HSSFSheet class in this example in order to make it
work with .xls files.
 The method is coded in such a way that I have used only six columns ,namely
VARIABLE NAME DATA TYPE METHOD NAME RETURN TYPE
with two columns to represent spaces.
 Here the excel sheet will be initialized only once . The same instance of
workbook(worksheet) class is passed alongwith same excel sheet object and the
object of the class(which holds the details)everytime when the replace method is
called. createSheet method will create new worksheet everytime when the replace
method is called.
In the replace method,
 The classname is assigned to the worksheet
 Data variable is created with TREE MAP which holds the key values ,method name
and its return type, variable name and its data type. In the simpler terms, data
variable represents a row.
 From getDeclaredMethods() and getDeclaredFields(), we can get the details of
methods and variables used in the classes.
 After that , rows are created in the excel sheet, and the data is set in the cells using
setCellValue(String) and setCellValue(Integer).
If we want to find out the details of the multiple classes, we can add the code in the way as
we have done with these two following classes
// Classname is PlaceEncoder
PlaceEncoder instance = new PlaceEncoder();
Class secretClass = instance.getClass();
mainProgram.replace(secretClass, workbook, out);
// Classname is FoodEncoder
FoodEncoder instance1 = new FoodEncoder();
secretClass = instance1.getClass();
mainProgram.replace(secretClass, workbook, out);

9. Outputs (1 of 2)

10. Outputs (2 of 2)

11. FROM THE WRITER
It has been great that I am here again to share
something with you .I am looking forward for your
responses. Your feedback means a world to me. I
am so grateful to all those blogwriters whose blogs
have helped me . To think that I've been of some
help to others, is humbling and deeply gratifying.
Thank you!
DEEPANSHU GUPTA
deepanshu.a.gupta@accenture.com