file Serialization

[abalfazl hossein]

Serial data is sent one element at a time, like a line of cars on an
assembly line

I read this in Java in 21 days book.But can't understand this.May you explain?

[fred rosenberger]

serial just means you have one pipe, and everything goes through it one at a time. you send the first bit, then the second, then the third, etc.

parallel means you have multiple pipes, so you can send more than one thing at a time. if you had 8 pipes, you could send each of the bits from a byte all at the same time, and the receiving end could re-assemble them.

[Henry Wong]

That "line of cars on an assembly line" seems like a silly analogy to me.

Henry

[abalfazl hossein]

So I can say:

Stream consist of serial bytes, In serialization, an object became serial of bytes in stream. That's why it called serialization.

Right?

[abalfazl hossein]

Anyone comfirm?

[abalfazl hossein]

File OurpurStreams write bytes to a file. ObjectOurputStreams turn
objects into data that can be written to a stream. So we make a FileOutputStream that lets
us write to a file, and we hook an ObjectOutputStrearn (a chain stream) on the end of it.

Can I say ObjectOutputStrearn is like a filter for FileOutputStream , so then stream write object?

[Stephan van Hulst]

Yes.

[abalfazl hossein]

A question:

At first, Does ObjectOurputStream serialize the object, then the object write on FileOutputStream?
Or Does FileOutputStream creates a stream, Then it's filtered by ObjectOurputStream?

[abalfazl hossein]

Think good 00. Each class
does onething well. File OurpurStreams write bytes to a file. ObjectOurputStreams turn
objects into data that can be written to a stream. So we make a FileOutputStream that lets
us write to a file, and we hook an ObjectOutputStrearn (a chain stream) on the end of it.

From �Head hhhhehehh
head first java

It is not still clear, Which one first?

[Mohamed Sanaulla]

abalfazl hossein wrote:

Think good 00. Each class
does onething well. File OurpurStreams write bytes to a file. ObjectOurputStreams turn
objects into data that can be written to a stream. So we make a FileOutputStream that lets
us write to a file, and we hook an ObjectOutputStrearn (a chain stream) on the end of it.

From �Head hhhhehehh
head first java

It is not still clear, Which one first?

You use FileOutputStream to write to a file. But for that you would need some data to be written to file. So for that you use ObjectOutputStream that uses the objects to create the data. First you would require an ObjectOutputStream, but to that you need to specify which file the data has to be store- so you also need a FileOutputStream. You are delegating the writing to a file to the FileOutputStream and ObjectOutputStream is concerned with creating the data to be written.

Internally ObjectOutputStream has a private class(and it extends OutputStream) which uses this OutputStream (FileOutputStream) passed in the constructor of ObjectOutputStream.

[abalfazl hossein]

I appreciate Mohammad

But there is question for

package fileimage;
import java.io.*;
public class Main {
    
      public static void main(String[] args) {

            int[] data = { 71, 73, 70, 56, 57, 97, 13, 0, 12, 0, 145, 0,
            0, 255, 255, 255, 255, 255, 0, 0, 0, 0, 0, 0, 0, 44, 0,
            0, 0, 0, 13, 0, 12, 0, 0, 2, 38, 132, 45, 121, 11, 25,
            175, 150, 120, 20, 162, 132, 51, 110, 106, 239, 22, 8,
            160, 56, 137, 96, 72, 77, 33, 130, 86, 37, 219, 182, 230,
             137, 89, 82, 181, 50, 220, 103, 20, 0, 59 };

             try {
                   FileOutputStream file = new FileOutputStream("pic3.gif");
                   for (int i = 0; i < data.length; i++)
                   file.write(data[i]);
                   file.close();
                   } catch (IOException e) {
                             System.out.println("Error — " + e.toString());
                   }
           }
       }
}

In this code data transfers without usage of object outputstream or dataoutputstream or....

But you told:

You use FileOutputStream to write to a file. But for that you would need some data to be written to file. So for that you use ObjectOutputStream that uses the objects to create the data.

[Mohamed Sanaulla]

You use ObjectOutputStream in case of Serialization. And for that you want the data in your objects to be written to the file. In otherwise usual cases you can manually write the data in the objects using FileOutputStream. Consider cases where the objects contain other objects and then that contain other objects- in this case you cannot keep obtaining the data from each instance and then write it to the file. You would need a simpler mechanism and that's where Serialization is used.

And in your example above its a simple case of writing some data to a file. And ObjectOutputStream doesn't come into picture here.

[abalfazl hossein]

Then ObjectOutputStream is like a person, that gets on a bus to go NW.and Bus is FileOutputStream here,

Or FileOutputStream is like a rail, and ObjectOutputStream is like a diesel wagon.

ObjectOutputStream gets on FileOutputStream and goes to destination.

Good example?

[Campbell Ritchie]

abalfazl hossein wrote: . . . Good example?

No

[abalfazl hossein]

Ohh.... I guess I understand it...May you tell me what is problem about my example?Thanks!

[Campbell Ritchie]

The streams do not take each other anywhere. They send data across themselves, altering the format of those data for their respective destinations.