DataOutputStream (a sample code from somewhere in the internet):

2.     try
3.     {
4. 
   
5.       FileOutputStream fos = new FileOutputStream(strFilePath);
6.       DataOutputStream dos = new DataOutputStream(fos);
7.       int i = 100;
8.       dos.writeInt(i);
9.       dos.writeFloat(123.21);
10.       dos.close();
11.  
12.     }
13.     catch (IOException e)
14.     {
15.       System.out.println("IOException : " + e);
16.     }

WORKS FINE!!!

DataInputStream:

2. String strFilePath = "C://WriteInt.txt";
3.   
4.  try
5.     {
6.       FileInputStream fis = new FileInputStream(strFilePath);
7.       DataInputStream dis = new DataInputStream(fis);
8.       
9.       println(fis.readInt());
10.       println(fis.readFloat());
11.     }
12.     catch (IOException e)
13.     {
14.       System.out.println("IOException : " + e);
15.     }

FAILS!!!

..it comes up with a compiler error. The error says that readInt() does not exist. Same with readFloat(). This is what I do not get about the DataInputStream class... how can it cause such errors, if the documentation says that it must work this very way? Maybe I am doing something wrong.. please enlighten me..

To my sadness, I have already explored the Object* routines and encountered a problem too. I have designed the class in a way that it's object stored the values in separate arrays of int and float types, and first I have filled the arrays with the values from other objects and then.. trying to write these properties I came across the above problem with the Data* things... Then I tried the Object* thing and when I pass to the writeObject(Object my_object) an array of integers, the method works just fine.. but when I try doing something with my custom SERIALIZED classes, it tells me things like PImage is not serialized or PApplet is not serialized, which I gues are hard-coded into Processing and I can't just change the things on the fly....  cannot convert from Object to sketch_aug17a.test_class is also another problem with reading objects form a file... So currently the problem is still not solved for me.

Also thanks for directing me to the "transient" keyword, I will check it tomorrow.. I am new to Java so I cannot understand the thing about the pure data class in deep, but I think that it is about creating an includable (or importable) java file with a serializable class containing all I need it to contain, or maybe I can 'implement' it with some of my Processing classes.. anyway, I will explore it too, and look for additional info in the net. If I will have some more questions, I will surely ask..

Thank you for now, guys!

If you don't have so much things to save/read or if you want to have a readable file, you can use XMLElement to store and read your parameters :

 

You can add a constructor to your class with a XMLElement parameter and using Float.parseFloat(string_to_parse), and Integer.parseInt(string_to_parse) tot retrieve your data.

 

For saving your XMLElement use java FileWriter class and a string representation of your datas :

strElement = "<file>";

strElement = strElement + "<width>"+width+"</width>";

... etc

strElement = strElement + "</file>";