SetAttribute() makes object serializable Recursively ?

          Hi everyone,
          could anyone answer me whether httpSession.setAttribute(key, very big object)
          makes the object serializable recursively.
          What I mean is, I am storing an object bigObject in http session using setAttribute().
          This bigObject contains several other objects which are not serialized.
          But I have read that setAttribute() makes the object serializable.
          So, does it mean that all the objects stored in bigObject also will be serialized
          thanks,
          jyothi

But you can't serialize an Object that isn't Serializable somewhere in it's
          inheritance. A method can't make an Object Serializable.
          "jyothi" <[email protected]> wrote in message
          news:[email protected]...
          >
          > But i read clearly some where in bea online manual that use
          setAttribute() which
          > makes the object searializable. So I wonder whether this
          setAttribute() does
          > the searlization recursively ?
          >
          > thanks,
          > jyothi
          >
          > "justin" <[email protected]> wrote:
          > >
          > >Cluster requirement is that all objects placed in a session should be
          > >serializable.
          > >So your Big objects with small object which are not serializable is going
          > >to be
          > >a problem.
          > >
          > >"jyothi" <[email protected]> wrote:
          > >>
          > >>Hi everyone,
          > >>
          > >>could anyone answer me whether httpSession.setAttribute(key, very
          > >>big object)
          > >> makes the object serializable recursively.
          > >>
          > >>What I mean is, I am storing an object bigObject in http session using
          > >> setAttribute().
          > >> This bigObject contains several other objects which are not serialized.
          > >>
          > >>But I have read that setAttribute() makes the object serializable.
          > >>
          > >>So, does it mean that all the objects stored in bigObject also will
          > >>be serialized
          > >>?
          > >>
          > >>thanks,
          > >>jyothi
          > >
          >

Similar Messages

2D objects Serialization problem

Welcome!
I'm making a net game using RMI and I have this problem.
When I'm trying to join my client with the server an error occures:
Error: error marshalling arguments; nested exception is:
     java.io.NotSerializableException: java.awt.geom.Ellipse2D$Double
My client contains an Object extending a JPanel class. There are 2D object used to make the map, and that's why this error occures.
It's a funny thing, cause I'm not sending a whole Object of my client, but only it's refference (using "this" in the join() method) so I dont know why does the 2D object need to be serialized and sent :|?
Any way, my question is how to make 2D objects serializable!? I have jdk1.5.0_06 and as far as I remember they should be srializable in this version. Mabey I'm dooing something wrong!? Mabey it's nessesary to ad an appropreate code-line or import sth... i don't know
please help me... I have little time to finish my project, and this thing is blocking my work.
Big thanks to anybodey who will help.
regards floW

I'll tel u the whole story then, my problem is as follows:
public class BounceThread{
   public static void main(String[] args)   {
      JFrame ramka = new BounceFrame();
         ramka.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
         ramka.setVisible(true);
class BounceFrame extends JFrame{
public BounceFrame()
      setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);
      setTitle("MiniGolf v 1.0");
      panel = new BallPanel(); // this contains maps made with 2D objects
      panel.setBackground(Color.green);
      panel.setVisible(panel.czy_widać_panel());
      add(panel, BorderLayout.CENTER);
// I add a menu bar, that starts a net game:
JMenuBar pasekMenu = new JMenuBar();
          setJMenuBar(pasekMenu);
          JMenu menuGra = new JMenu("Game");
       // and so on... and finaly I add an option:
          menuGame_Nowa.add(new
                    AbstractAction("Net game")
                         public void actionPerformed(ActionEvent event)
                              net_game(panel);
// here i write my net_game method:
public void net_game(BallPanel aPanel)
     //here, i make an Client object, and connect him with my server
     client = new mgClient(panel);
     client.join();
     // I give panel as a paramete, cause I cant think of another way of leting my server to uce it's (panels) methods
     // If I join only a name of my client, then how can I change the panel in my BounceFrame from the Clients method
     // "shouted" by the server!? It has to be a field in the client's object.
     // Is there any other way out!?
// Class BouceFrame holds the panel as a field:
private mgClient client;
private BallPanel panel;
//and so on...
}and that's the real problem I'm facing here. Is there any solution!? I think, that making a Client's field out of my panel is the only way ot. And that means I need those 2D objects serialized... :(
Please help if u can.
Regards floW

Runtime Object serialization

Hi,
Could someone explain the concept of Runtime Object Serialization with a simple example?
Thanks

import java.io.*;
/* you NEED to make the class implement Serializable */
class Client implements Serializable {
    private String name;
    private String address;
    public String getName() { return name; }
    public String getAddress() { return address; }
    public void setName(String name) { this.name = name; }
    public void setAddress(String address) { this.address = address; }
    public String toString() { return "name='" + name + "' and address= " + address + "'"; }
public class Test17 {
    public static void main(String[] args) throws Exception {
        ObjectOutputStream oos = new ObjectOutputStream (new FileOutputStream ("test.bin"));
        Client myClient = new Client();
        myClient.setName("Steve Jobs");
        myClient.setAddress("1 Infinite Loop; Cupertino, CA 95014");
        System.out.println (myClient);
        oos.writeObject (myClient);
        oos.close();
        ObjectInputStream ois = new ObjectInputStream (new FileInputStream ("test.bin"));
        Client yourClient = (Client) ois.readObject();
        System.out.println (yourClient);
}Run the program above. It creates an object of the class "Client", serializes it into a file named "test.bin" and recreates the object reading it from the same file.
Dumping the binary file you get this:
0000    AC ED 00 05 73 72 00 06 43 6C 69 65 6E 74 F1 D7   ....sr..Client..
0010    74 76 C4 64 FD 43 02 00 02 4C 00 07 61 64 64 72   tv.d.C...L..addr
0020    65 73 73 74 00 12 4C 6A 61 76 61 2F 6C 61 6E 67   esst..Ljava/lang
0030    2F 53 74 72 69 6E 67 3B 4C 00 04 6E 61 6D 65 71   /String;L..nameq
0040    00 7E 00 01 78 70 74 00 24 31 20 49 6E 66 69 6E   .~..xpt.$1 Infin
0050    69 74 65 20 4C 6F 6F 70 3B 20 43 75 70 65 72 74   ite Loop; Cupert
0060    69 6E 6F 2C 20 43 41 20 39 35 30 31 34 74 00 0A   ino, CA 95014t..
0070    53 74 65 76 65 20 4A 6F 62 73                     Steve JobsYou can see a lot of things in the serialization of the object Client - the name of the class is written, the names of the fields, the type (java/lang/String), and the values of the fields as UTF-8 encoded strings.

Can we make Object whih is ...............

Hi friends
can we make object which is live for whole JVM life?
means once object is created then it will be not destroyed untill JVM killed.
and also we uses that object or not it should remain in JVM.
GC should not kill that object.
can anyone tell me idea or code to do this.
thnx in advance

No, unless you manage to keep a reference to it the whole time, like making a static reference to it in the class that has the main method. Though technically, this still wouldn't ensure that it's available during the whole JVM lifecycle I think, but in your case it might be sufficient.

Servlet and Object Serialization

Hi,
I am developing a routing server in Java
2 Instances of the same server will be running in 2 different data centers.
The servers have a Jetty server embedded with a Servlet inside.
Server 1 will use a GET method to talk to the Server 2 -> Servlet which will write the state of an object back which will read by Server 1 and reconstruct the object back.
Do you find any issues in Object Serialization/DeSerialization in the Servlet.
What are the factors that I need to consider in this case?
Regards,
Jana

Make sure that your servlet handles the transaction in the same thread that doPost() or doGet() is called in.
I ended up porting some old ServerSocket based code to a servlet, and was handing off the request and response objects to a handler thread on the server side. I ended up with a ton of intermittent errors like this.
Once I started handling the transactions in the same thread things worked heartbreakingly well.

How do I make objects fade in when scrolling?

How do I make objects fade in when scrolling? Thanks!

Do you know of a way to make Edge animations play when scrolled into view on a Muse website?
Apple does this well here: http://www.apple.com/ios/ios7/features/

HttpSession.setAttribute( name,object ) object- vector

In HttpSession we have void setAttribute(name,object)
and object getAttribute(name
In this can i set the vector as an object in
setAttribute(name,object) and retreive the vector by
casting in the getAttribute(name) ?
The code ....
Vector v = new Vector();
// adding elements in vector
session.setAttribute(name,vector);
Vector recV = (Vector)session.getAttribute(name);
is it possible ?
Thank you
elango

Yes. Session.setAttribute(), ServletContext.setAttribute(), etc. are all dictionary lookups.

Customizing Forte object serialization

Forte supports serialization of arbitrary object graphs into streams.
However, there do not seem to be any well documented ways to customize
this serialization, e.g. by using a different encoding scheme. It would
seem there must be some support in there somewhere. I suppose at the
very least, one could parse a serialized object (once one decoded the
Forte encoding scheme) and do the conversion from that. That seems
suboptimal, though.
Has anyone done this? Any thoughts on how it might be done?
Regards,
Coty
To unsubscribe, email '[email protected]' with
'unsubscribe forte-users' as the body of the message.
Searchable thread archive <URL:http://pinehurst.sageit.com/listarchive/forte>

JavaFunda wrote:
Object serialization is the process of saving an object's state to a sequence of bytes. Does it saves only the instance variable or also the object methods(like getter and setter methods) ? Only the state--the instance variables. It doesn't save the class definition. That has to be available separately (via classloader) at deserilaization time. In other words, you cannot deserialize an instance of a class that is not on your classpath.
Once we we write the object to outputstream or some text file, how does it get transmitted over network?The same way any other bytes get transmitted. You have a Socket. You get its OutputStream. You wrap that in an ObjectOutputStream. When you write to the ObjectOutputStream, that writes through to the Socket's OutputStream, which is responsible for putting the bytes on the wire.
Does we write the java object to text file only duuring serialization?We write the objects to wherever the other end of the ObjectOutputStream is connected to. Just like any other I/O.

Install LiveType data button is dimmed and Can I make objects myself?

Is it normal that the Install LiveType Data button is dimmed?
How can I install new textures and object?
And my second question is can I make objects myself?

Werner C wrote:
Is it normal that the Install LiveType Data button is dimmed?
Umm, no. but you haven't told us aything about yoru installation procedure. It might be normal for what you're trying to do.
How can I install new textures and object?
Push the install button.
And my second question is can I make objects myself?< </div>
This is your third question. The short answer is yes but it's much more complicated than that. In previous editions of LT, there was an application that allowed you to create your own LiveFonts and other goodies but it's not on the the v3 installation script that I can tell. Your best bet is to figure out why you cannot run the installer properly and fix it.
bogiesan

Object serializable?

Hi,
When writing a vector of my own objects out to a file, do the objects need to be serializable even though it is actually the vector I am outputting?
Also, each of my objects in this vector have a field that is a vector of other objects...do I need to declare those objects serializable also?

I think you still need to implement serializable on objects contained in the vector. I tried serializing a hashmap and my hashmap contained objects which needed to be serialized before the hashmap could be stored in a file.

Object serialization failure during OutOfMemory error (EOFException)

Hello all,
We are seeing a very strange situation when writing a serializable object to a flat file, specifically during an OutOfMemory condition. Our application saves the state of an object if an error occurs, and retries at a later point by reviving the object from its serialized form. We recently encountered a series of EOFExcetions when trying to reload the serialized object. Looking at the serialized data, we see that the file is indeed incomplete, and that it appears to be the serialized representation of the data contained within the object that is missing (the structure of the object appears to be stored in the serialized file, but not the runtime data).
The code that produces and consumes these serialized objects is used in a variety of locations, and even in the case where these EOF errors occurred usually works as expected. The difference appears to be that the error condition which lead to the object serialization was in-fact an OutOfMemory error. That is, we had an OOM error elsewhere in our application, which caused our objects to be serialized to disk. During this serialization process we end up with corrupt (incomplete) serialization data.
So.. the question is: Is it possible that the OutOfMemory situation causes the JVM to incorrectly serialize an object (without an error), and specifically to omit runtime data (variables) from the serialized form of the object?
Thanks/

jasonpolites wrote:
So.. the question is: Is it possible that the OutOfMemory situation causes the JVM to incorrectly serialize an object (without an error), and specifically to omit runtime data (variables) from the serialized form of the object?you're sure that the serialization process completed without an error? how do you know the the OOME did not cause the serialization to fail (because the serialization process itself will require more memory, hence if it is happening while the system is near the memory peak, it is likely to fail as well)? generally, when a jvm starts throwing OOME's all bets are off. failures in random places can easily cause the whole internal state of a system to become invalid.

Object serialization EOFException

Essentially what I want to do is write to an object to a file. The program can terminate and then when I start the program again, it will read the object from the file and restore the program's original state before it was terminated.
I get an EOFException with this code
//insert code that gets input which will be stored in a hashtable
//save Hashtable in "data.dat" using ObjectOutputStream
//program terminates
//program is re-ran again and checks for existing file
File f = new File("data.dat");
if(f.exists()){
ObjectInputStream ois = new ObjectInputStream(new FileInputStream(f));
Object obj = ois.readObject(); //EOF exception occurs here
}I know the above code works if I write the Hashtable and then read it back immediately without terminating in between. Am I missing something? Can object serialization be used in such a way that I can restore a program's original state before it was terminated?

Sorry, I led you to believe that the actual class itself was going to be written to a file. I meant to say that the Hashtable in the class should be written to a file and then later on when I start the program again, it will restore the Hashtable to it's original state.
My writing coding is something like this:
Hashtable accounts = new Hashtable();
//do stuff to the hashtable
FileOutputStream fos = new FileOutputStream("data.dat");
ObjectOutputStream oos = new ObjectOutputStream(fos);
oos.writeObject(accounts);
//Program can be terminated from this point
//there is no further oos.writeObject() if it wasn't terminated
//immediately after the above writeObject() call
//Program is ran again and at startup it checks for existing file
File f = new File("data.dat");
if(f.exists()){
ObjectInputStream ois = new ObjectInputStream(new FileInpuStream(f));
Object obj = obj.readObject(); //EOFException occurs here
}Again those lines work perfectly fine if I do not terminate the program and I force it to check for an existing file. If I terminate, it's almost as if the program thinks there's nothing in "data.dat" eventhough it's obvious by my code that I did write something to "data.dat".

SetAttribute(String, Object) error

Hello Guys,
I have in my jsp page something like this.
request.setAttribute("variable",0). When i load the page, it comes with an error saying that
Generated servlet error:
The method setAttribute(String, Object) in the type HttpSession is not applicable for the arguments (String, int)
I tried various things like
Integer v = new Integer(0);
Integer.valueOf(0).
But it comes up with the same error.
Any ideas?
Help would be appreciated.
Kay

The method setAttribute(String, Object) in the type HttpSession is not applicable for the arguments (String, int)This says it all. setAttribute() doesn't work for primitives, it only takes Objects. So you have to use an Integer and not an int. A String will work fine too.

How to make Object class to be serializable?

I'm writing a session bean which contains an Object[][] as a return e.g
public Object[][] getFoo(){
I need the return to be of type Object since I'm constracting a 2D array of different object types e.g Integer, Double, HashMap, String etc. But EJBs require serializable objects for their public remote methods. Could you please advice me whether there is another class that I could use instead of the Object class to be serializable? I'm still using SDK1.3.1.
Thank you

I've already tried that before, but it doesn't work. When I try to assign different objects to my array as in the following example:
ABC[][] abc = new ABC[4][2];
abc[0][0] = new Integer(1);
abc[0][1] = new String("abc");
abc[0][2] = new HashMap();
I'm getting compilation error since Integer, String and HashMap can not be casted into ABC. My question is whether there is such a class (part of the SDK) which implements Serializable AND these classes can be casted to, as in the above example?

Object Serialization(Materialization and Dematerialization)

I've encountered some issues with mapping my objects to an RDBMS and am hoping for some advice.
I've tried various O/R mapping frameworks like Castor(too complex and too slow for my liking), JRF(nice but very repetitive and difficult to extend) and then some, but have yet to find one which I'm comfortable with building an application on.
Instead, I've chosen to do it the low-tech way, with each domain class, say Book for instance, having a Broker class which knows how to communicate with the chosen form of persistence. So, since I chose an RDBMS, Book class has a BookRelationalBroker class which knows how to materialize and dematerialize Book objects to and from a RDBMS. If so required, I can plug in a BookXMLBroker which knows how to serialize the object in the form of an xml data file.
I've also implemented a primitive object caching system which (when enabled), caches objects requested so we only have to materialize it from the db once.
Here are 2 issues I have with my system:
It is amazingly tedious (not to mention inefficient) to recreate the entire object from the database. This is even more so because I've implemented the Event Notification pattern, such that when say a book is deleted, the members who have reserved it are notified. The whole point of the Event Notification mechanism is so that the object being watched does not need to know of the objects which need to be notified on a state change. However, I've found it necessary to re-attach all the listeners on an object when it is materialized from the DB, defeating the purpose of the pattern.
Complex object relationships are mapped poorly and recursive materialization leads to slow response times. If a Group object has a Vector of Members and other Groups, then whenever a Group object is materialized, all its constituent Members and Group objects also need to be materialized. (I understand O/R frameworks solve this through lazy instantiation)
I studied the Jive2 architecture and found that they approached this problem by accessing the DB directly for any complex object relationships. In other words, the Group object does not actually contain a Vector of Members and Groups. Instead, it has a method called say getMembers() which proceeds to retrieve the necessary data from the DB and then materialize these objects.
I'm not too excited about this approach for 2 reasons:
How object-oriented is this approach? Seems more like database-oriented programming to me.
Every call to retrieve Members necessitates a call to the DB. The data isn't cached with the Group object because the Group object does not actually contain the necessary reference to the Members and Groups.
Can anyone shed some light on this topic?

How object-oriented is this approach? Seems more like database-oriented programming to me. There is a reason people still use Relational databases rather than OO DBs. First, is that the vast majority of data in the real world maps easily to a relational model, consequently there is no advantage to a OO model. Second, either because of this or simply because OO models are not computationally simple, OO databases tend to be slower than relational DBs.
It sounds like you are trying to implement a OO DB model using a relational database. So you basically end up with two problems. The DB is not optimized for OO models, and you have to find a way to map it in the OO model itself. And this is slow and messy.
To solve the slowness problem you could, just like EJB servers, cache the data in memory. Lot of work but if you want to do it then have fun.
The second way is to give up. Realize that your data model is not inherently OO'd and just implement it efficiently as a relational model. Then provide an interface that loads it into the OO model. And where needed add pass through logic to allow the database itself to do things it is really good at - like queries.

SetAttribute() makes object serializable Recursively ?

Similar Messages

Maybe you are looking for