Serialisation

Hi

Yes sorry you are right it's deserailizing, but i don't think its a question of not writing all to the stream.

I completely analyzed the input and outputstream, when all goes well (rows with the current date) i am writing 21078 bytes to the stream and also exactly reading

the 21078 bytes.

When i use a different date i also write 21078 bytes to the stream but the deserailizing process tries to read more?

I really don't know but this seems like a bug to me.

Jos...a at 2007-7-10 2:13:07 >

Hello

Code is like this,

(I am reading from a RandomAccessFile called file.)

public Object[] getContents() {

int len = file.length();

ArrayList<Object[]> list = new ArrayList<Object[]>();

while(file.getFilePointer() < len){

doRead(); // this fills up a String name, a short version and a long

// modified

// .. Breaking up String name in 3 parts (path, nm, type)

Object[] row = new Object[]{

path,

nm,

type,

new Short(version) ,

new Date(modified)

}

list.add(row);

}

// .. About 200 rows in list.

Object[] ret = list.toArray(new Object[list.size()]);

return ret;

}

//....

public void someMethod() throws Exception{

Object[] data = getContents();

ObjectOutputStream oos = new ObjectOutputStream(

new MyOutputStream());

//MyOutputStream is simple a extension of OutputStream

// that buffers all the bytes written to it so they can be send across

// the network.

oos.writeObject(data);

oos.close();

...

}

// ... Method on client side receives the serialised Object,

//the byte[] is set to a inputStream and returns -1 when the end

//of the byte[] is reached

public void receive(byte[] bb) throws Exception {

ObjectInputStream ois = new ObjectInputStream(

new MyInputStream(bb));

Object[] rows = (Object[])ois.readObject();

ois.close();

}

Jos...a at 2007-7-10 2:13:08 >

Why does MyOutputStream has to handle flushes at all?

The only method implemented there is the one declared abstract in java.io.OutputStream.

public void write(int b) throws IOException

Closing the ObjectOutputStream causes this method to be triggered, also writing the last bytes.

Where do i go wrong, HELP.

Jos...

Jos...a at 2007-7-10 2:13:08 >

Forget the flush. Closing the ObjectOutputStream will flush and close it and all the strreams it is built over including the MyOutputStream. Although what's wrong with using BuffferedOutputStream instead of writing your own is a mystery to me.

I'm more interested in how the OP does deserialization from a RandomAccessFile, and why.

ejpa at 2007-7-10 2:13:08 >

I don't understand a word of that.

(a) Why don't you use anObjectOutputStream over a BufferedOutputStream and write directly to the network like everybody else? Forget the buffer, forget the bytes, they will disappear down the network without you having to write an extra class.

(b) I didn't ask why you were serializing a RandomAccessFile.The question would be meaningless. I asked why you were deserializing from a RandomAccessFile. This is rather hard to do as you can't just stack an ObjectInputStream over it, you have to deal with the bytes directly and interpose a ByteArrayOutputStream or some such.

(c) As serialization has been working with primitive and object data for about eleven years, it's a pretty fair bet that all your problems are stemming from these extra complication you're introducing into both phases of serialization. But as you haven't shown us any of it, it's impossible to be more specific.

ejpa at 2007-7-10 2:13:08 >

> a) I am working with channels (java.nio) and in order

> to use them you have to fill up ByteBuffers and that

> can be done with a byte[].

OK

> b) I don't understand, why do you think i am

> deserializing from a RandomAccessFile?

> I only try to deserialize some data read from a

> RandomAccessFile

I can't see any difference between these two statements, and I stlll don't know why you can't use a FileInputStream and an ObjectInputStream on top of it.

> i only state

> - sometimes there is a problem using an long (new

> Date(modified)

Until you show us the code that serializes the object as well as the code that deserializes it we are all guessing.

ejpa at 2007-7-10 2:13:08 >