After hours fun exercise 01: IntegerAdder for people fancy using args from main(String[] args) method.

HONEST WARNINGS:

• I have only 3 years of experience as professional with many things to learn left,so keep in mind that this source code and program are NOT masterpiece of software engineering
• Do not learn programming style from me. If you want good programming styles. Download source code for Apache Commons.
• My solution as simple as possible,not as best as possible.
• Comment can contains lots of sarcasm.
• I do this for fun , learning or practice purposes.

ABOUT EXAMPLE

This is a very simple example of using args from main(String[] args) method.

MISSION OBJECTIVE

1. I wanted to learn how to use GitHub ;)
2. (I have many experience with using args,but i want to reuse one of my code)

WHAT THIS EXAMPLE DO ?

* It will take arguments and each argument is a path to file.
* Each file can have any number of lines from 1 to N.
* Each line can contain only one integer.
* All of the numbers from all of the files should be added to the final result.
* The result is just one number and it will be displayed usingS System.out.println() method


If you don't copy and paste code,then simply download from program from GitHub
https://github.com/pastorcmentarny/java.examples.integeradder

For simple  cases of  command line attributes.It is enough.
If planning to crazy things  and perfom lots of magic then I suggest to use libraries like:
http://commons.apache.org/proper/commons-cli/

:)

RESOURCES:
Java's tutorial
http://docs.oracle.com/javase/tutorial/essential/environment/cmdLineArgs.html
http://commons.apache.org/proper/commons-cli/

CODE

IntegerAdder class

package dms.pastor.integeradder;

/**

*

* @author: Pastor cmentarny

* #WWW: http://pastor.ovh.org

* #Github: https://github.com/pastorcmentarny

* #Google Play: https://play.google.com/store/apps/developer?id=Dominik+Symonowicz

* #LinkedIn: uk.linkedin.com/pub/dominik-symonowicz/5a/706/981/

* #Email: email can be found on my website

*

* This is an example of using args from main(String[] args) method.

*

*

* About program:

* It will take arguments and each argument is a path to file.

* Each file can have any number of lines from 1 to N.

* Each line can contain only one integer.

* All of the numbers from all of the files should be added to the final result.

* The result is just one number and it will be displayed usingS System.out.println() method

*/

public class IntegerAdder {

/**

* @param args the command line arguments. Each argument should be a valid path to file.

*/

public static void main(String[] args) {

int sum = 0;

Adder adder = new Adder();

if(args != null){

for (String integer: args) {

sum += adder.add(integer);

}

}else{

Utils.error();

}

System.out.println(String.valueOf(sum));

}

}

Adder class

package dms.pastor.integeradder;

import java.io.BufferedReader;

import java.io.File;

import java.io.FileInputStream;

import java.io.InputStreamReader;

/**

*

* @author: Pastor cmentarny

* #WWW: http://pastor.ovh.org

* #Github: https://github.com/pastorcmentarny

* #Google Play: https://play.google.com/store/apps/developer?id=Dominik+Symonowicz

* #LinkedIn: uk.linkedin.com/pub/dominik-symonowicz/5a/706/981/

* #Email: email can be found on my website

*

* Adder is response for sum of numbers from file.

*/

public class Adder {

public int add(String path){

File inputFile = readFile(path);

FileInputStream fis;

InputStreamReader isr;

BufferedReader br;

int sum = 0;

try {

fis = new FileInputStream(inputFile);

isr = new InputStreamReader(fis, "UTF-8");

br = new BufferedReader(isr);

String strLine;

while ((strLine = br.readLine()) != null) {

sum += Integer.valueOf(strLine);

}

} catch (Exception e) {

Utils.error();

}

return sum;

}

public static File readFile(String filePath) {

if (filePath == null || filePath.equals("")) {

Utils.error();

}

try {

File file = new File(filePath);

if (file.exists() && file.canRead()) {

return file;

} else {

Utils.error();

}

} catch (Exception e) {

Utils.error();

}

return null;//Yes, I know is crap,but i have done this way for simplicity reasons.

}

}

Utils class

package dms.pastor.integeradder;

import java.io.BufferedReader;

import java.io.File;
import java.io.FileInputStream;
import java.io.InputStreamReader;

/**

*
* @author: Pastor cmentarny
* #WWW: http://pastor.ovh.org
* #Github: https://github.com/pastorcmentarny
* #Google Play: https://play.google.com/store/apps/developer?id=Dominik+Symonowicz
* #LinkedIn: uk.linkedin.com/pub/dominik-symonowicz/5a/706/981/
* #Email: email can be found on my website
*
* Adder is response for sum of numbers from file.
*/
public class Adder {
public int add(String path){
File inputFile = readFile(path);
FileInputStream fis;
InputStreamReader isr;
BufferedReader br;
int sum = 0;
try {
fis = new FileInputStream(inputFile);
isr = new InputStreamReader(fis, "UTF-8");
br = new BufferedReader(isr);

String strLine;

while ((strLine = br.readLine()) != null) {
sum += Integer.valueOf(strLine);
}

} catch (Exception e) {

Utils.error();
}
return sum;
}

public static File readFile(String filePath) {

if (filePath == null || filePath.equals("")) {
Utils.error();
}
try {
File file = new File(filePath);
if (file.exists() && file.canRead()) {
return file;
} else {
Utils.error();
}
} catch (Exception e) {
Utils.error();
}
return null;//Yes, I know is crap,but i have done this way for simplicity reasons.
}

}