Swing/AWT/SWT :: Sending Serializable Object Between Two JFrames
May 2, 2014
I have two JFrames the first one is a log in screen where i log in to the log in server that i made using RMI . If the log in succeeds i send the user object witch is Serializable to the second JFrame.
The user object is received from the server. This object contains all the information needed in the second JFrame. This second JFrame is made inside the first one and i defined a method with witch i send this user object to the second frame.
Now the problem arises , while inside this method i am able to read all the data i need from the user object. At the end of the method i save the reference of this object in a new User object defined in the second JFrame ,because i need it later on.
But soon as this method finishes , for some reason my reference to the object becomes null , and i cant use it later on.
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Dec 10, 2014
This program is basically complete. It compiles and runs. It is a college course assignment that I pretty much completed but for the last part in which I'm suppose to change the values of all fields and display the modified values using a toString method. Modifying the values of the fields is where I am stuck. I don't think I need to create a new text data file to do this. The instructor only asked that all the values of fields be changed and this was the last part of the assignment so I don't think it involves creating additional ObjectOutputStream and ObjectInputStream objects. I'm getting a NullPointerException error on line 161.Here is the code. I'm also including the input data file.
//create program so that objects of class can be serialized, implements interface Serialiable
//create constructor with 4 parameters with accompanying get and set methods, Override toString method
//create text file with 5 records, create Scanner object,ObjectOutputStream, and ObjectInputStream
//create new ItemRecord object, change values of all fields in ItemRecord object using object's set methods
//modify ItemRecord object using toString method
[hightlight =Java]import java.io.Serializable;
public class ItemRecord implements Serializable
[Code] .....
This is the error message:
----jGRASP exec: java ItemRecordReport
Item Cost Quantity Description
Number
A100 $ 99.99 10 Canon PowerShot-135
A200 $149.99 50 Panasonic-Lumix T55
A300 $349.99 20 Nikon- D3200 DSRL
A400 $280.99 30 Sony- DSC-W800
A500 $ 97.99 20 Samsung- WB35F
Exception in thread "main" java.lang.NullPointerException
at ItemRecordReport.main(ItemRecordReport.java:161)
----jGRASP wedge2: exit code for process is 1.
----jGRASP: operation complete.
Here is the data file:
A100 99.99 10 Canon PowerShot-135
A200 149.99 50 Panasonic-Lumix T55
A300 349.99 20 Nikon- D3200 DSRL
A400 280.99 30 Sony- DSC-W800
A500 97.99 20 Samsung- WB35F
Here is the data file for the modified field values.
B100 98.00 10 ABC1010
B200 97.00 15 DEF1020
B300 96.00 10 GHI1030
B400 95.00 05 JKL1040
B500 94.00 01 MNO1050
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May 23, 2014
I'm writing a small program in Java to simulate a shopping cart. A shopping cart has an array og objects Item. As a console application, my program runs.But, in the GUI version, I have some issues. In class MainMenu I create a ShoppingCart object, named "cart"(line 103)In class AddItemMenu I create an Item object, and I want to add it in my ShoppingCart object "cart".BUT, AddItemMenu cannot "see" variable "cart".
//MainMenu.java
package shoppingcartgui;
public class MainMenu extends javax.swing.JFrame {
public MainMenu() {
initComponents();
[code]....
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Sep 28, 2014
I'm just messing around with JFrames and stuff like that (like previous posts). There is no ultimate goal here, which I realize violates that I should write everything down beforehand and know what I'm trying to accomplish. My question is, does this look ok? I'm going to start doing if...else statements but don't want to move on if I think this is bad programming. Any tips on how I create new JFrames under and if...else statement?
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
[code]...
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Mar 20, 2014
All I need to do is show in just one JFrame the two combined JFrames. One JFrame namely leftPanel will appear to the left or west and the other namely rightPanel to the right or east using BorderLayout. I already did creating them first as JPanels or as internal classes and subsetted them in one JFrame but that didn't work because it looked messy. And now I've created them as two separate JFrames, compiled separately, and tried to subset them as one in the JFrame. I didn't add any functionality to this program because all I intend to do is to show those two JFrames together in one JFrame. Here's the code:
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class dirtyIceCream extends JFrame {
leftPanel westPanel;
rightPanel eastPanel;
public dirtyIceCream()
[code].....
What am I missing or did I code anything wrong here? Or should I use NetBeans IDE for anything as complicated as this?
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Mar 29, 2014
I'm struggling with a small project. I have 2 jFrames. The first frame has a button that...
- Display's the second frame containing a progressbar
- Starts a heavy processing thread
I need to update the progressbar on the second jFrame, from a thread started on the first jFrame.
I have 2 problems:
- How do I update the progressbar?
- When the button is clicked, an empty second frame is displayed with no controls. The controls are only rendered/shown, after the large thread process is finished...
I've attached to this post a small screenshot, showing the main idea ...
Source code:
Button action on the first frame:
private void btnGoActionPerformed(java.awt.event.ActionEvent evt) {
Progress progress = new Progress(); // The second frame
progress.setVisible(true);
clsProcess myProcess = new clsProcess(); // The thread process
myProcess.start();
[Code] ....
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Apr 17, 2014
I have two programs that I'll post below, one is a Server and the other is a Client. The ChatServer runs once and many clients can run ChatClient from separate computers and talk together in their GUI's. The the client program comes with two buttons, one that's simulates the sending of a message to a single user ; "Send Message To User", and one that just generally sends a message ; "Send Message To All". Although now the Clients on the server seem to be able to selectively send messages to an individual by giving the recipient name, all the clients can see that message, which is not exact what I am aiming for. What I am going for is having the "Send Message To User" button click to send a message to the named user without all other users seeing the message.
The Server Program Code
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
[Code] ....
Now I have tried thing like having various input output streams and trying to connect those, but no luck. Tried fiddling with having the names arraylist directing the messages to one client versus all but that did not work out either. How I what I would need to do to go about doing this?
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Nov 3, 2014
For a class, I'm making a prison system program. The prison has cell blocks, each cell block has cells, each cell has bed(s), and each bed has prisoners. There are also visitors and visits. I thought, rather than write all of those to different files, I could just write the entire prison to a file and make all the classes under it implement serializable. The instructor said that is a bad practice and we shouldn't do it. So I'm thinking I'll make the prison non-serializable. But the prison has maps of cell blocks, inmates, visitors, and visits. I think I'll make all those serializable and I'll also make everything a cell block contains serializable as well. Then I can just read the cellblocks from the file. But is that too easy as well? Is that a bad practice?
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Feb 5, 2015
Why is it that objects stored in session object should be serializable?
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Mar 27, 2015
can a keyevent in java make the space ship and the laser too ?
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Jan 15, 2015
What I want to do is have a label that is updated whenever an object gets some new, relevant data.The way you do it in Java looks different from the way we do it in Objective-C. In Objective-C, we have what's known as a protocol. An Objective-C protocol is almost exactly like a Java "implementation." In Obj-C, if I want the user to see the address of where he is, I can have an object that gets the information and invokes a view controller's method; at that point, the view controller would then take the data passed to it and display the data in a label. However, the view controller is an instance of a subclass of the bundled view controller class.
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Jun 11, 2014
I am trying to find either some references to point me on the right track with passing an object with all of it's properties still in tact after it's been created. Currently I am trying to do this through an interface but it seems to just create a new object everytime without the properties. Example below :
import java.util.ArrayList;
import java.util.List;
public interface TPerson{
//public Person p = null;
}
class Thrower {
Person p;
[code]....
When I implement the interface on the other objects as soon as I call the setP method shown above it seems to just create a new one even though I pass the object to the method I want to use.
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Jul 27, 2014
I am currently working on a project where I need to return data from a database over RMI to a client who requests it. Some of the fields in the Data Object can not be seen by the client so I need to create another object to send over the network instead. The method I use is this...
public static SerializableObject createSerializableObjectFromDataObject(DataObject dataObject){
SerializableObject serializableObject = new SerializableObject();
serializableObject.setField(dataObject.getField());
serializableObject.setAnotherField(dataObject.getAnotherField());
return serializableObject;
}
Is there a better way of doing this? I am creating many subclasses DataObject which all require this static method to be implemented and I can't push it into the superclass because each one needs custom behaviour.
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Feb 28, 2015
java.awt.Component is an abstract class, and it's direct Sub-classes are Button, Canvas, Checkbox, Choice, Container, Label, List, Scrollbar, Text Component
So, when I use addXListener(mylistenerclass m);//which is a method of Component class which object is holding the list of all listeners, for a particular Event Source?
I am under the assumption that - there is an Event Source Object(possibly static) for every Event Source type(mouse, keyboard etc) that holds a list of destinations(classes that implements their listener interface) - added to the the object via addXListener method. When an event happens(mouse click, drag etc) the Event Source Object creates an Event Object and send it to all the destinations. Is my assumption correct? I can't seem to find the location or declaration of Event Source Object and the list where it stores it's registered destinations.
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Aug 13, 2014
I'm not even sure if that is the right question to ask. I've been confused by what is A Graphics object for a while now, I used to think that it is simply a tool to use to change colors and draw to specific container(ie JFrame, JPanel). However, I've been studying buffering(triple, double, flipping...etc) and how it works for 3 days now, and my confusion has only increased. for instance, why when we need to draw to the buffer(ie BufferStrategy, BufferedImage) we get its own graphics object to draw to it and then we project it to the screen?
Does the Graphics Object represent the drawing surface (ie the JPanel it self if we're using one to draw custom painting via JPanel#paintComponent(Graphics g)) ? and so when we're getting the graphics object of a buffer, do we actually get its drawing surface to paint on?
So generally speaking if we are using a JPanel and we say bufferedImage#createGraphics and use that graphics object to draw to, we would not be drawing to the JPanel but to the BufferedImage correct?
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Nov 13, 2014
I' currently wrking on BeatBox application from Head First Java. I made a jpanel the pane of the frame & when i try to add a JMenuBar object to that it is not getting displayed when i run the code. When i add a menuBar directly to the JFrame object it is visible & working fine but not incase when added to JPanel.
package com.java.BeatBoxGUI;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Font;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
[Code] .....
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Sep 22, 2014
I’m teaching myself Java. I am a fairly proficient programmer in other languages, but this is the first OO language I’m doing.I have a question that is a bit hard to summarize. Or it should be: how can I pass on an object (or variable) to an event listener?
I am writing an application in which you can play a Sudoku game. I have separated the “logic” or the “model”(the classes with Sudoku data structures and methods to manipulate them) from the presentation (the view and the controller).The main method starts off as follows:
SudokuModel model = new SudokuModel();
SudokuView viewController = new SudokuViewController(model);
The first line creates class for the logic and the second line creates the class for the view and the controller. Since the view and the controller need access to the business logic, the model is passed on to the ViewController class.The SudokuViewController class creates the user interface in Swing and it handles the user input. For the user input I have created a number of listeners, like this:
table.addKeyListener(this);
Now these listeners need access to the model since they update it. However, as far as I’m aware the only parameter passed on to an event listener is the event itself. So these event listeners do not have direct access to the model, even though it is passed on to the constructor of the class SudokuViewController.
To circumvent this, I made model2 an attribute (variable) of the class SudokuViewController. The constructor of the class sets this variable as follows:
model2 = model;
Now the event listeners have access to model2, which they can manipulate.This works. However, I think it is an ugly solution, introducing an additional object (model2). I’d like to pass on the object named model to the event listener, but this doesn’t seem to be possible.
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May 28, 2014
I have a number of cells which are Dates and need to have them appear in the same format. The samples I have seen usually create a new cell renderer object for each cell, even if its the same type. Since I have a number of Date cells I thought it best to use a single object for each of the date cells, but after seeing the different samples I am wondering if there is something I may be missing where using the same cell renderer object could potentially be an issue.
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May 14, 2014
I'm trying to create a table where the Header is a custom object.
The custom object would be something along the lines of
public MyColumnObject
{
String myLabel;
ArrayList dataForDropdowns;
int defaultColumnIndex;
int modifiedColumnIndex;
String tooltip;
}
This is simpler then what I want to do, but it's the basic concept. I want the column header to render the myLabel for the visual (at least at first). I want this render to be applied to however many columns I have, which will differ from table to table, but I always want the column header of each column to be of type myColumnObject.
I thought somethinglike this would work, but I'm getting java.lang.ClassCastException: java.lang.String cannot be cast to myColumnObject which makes sense, but I thought that I would be getting back my object.
p.s. I re-labeled all my code from my actual project, so if something looks off, it was probably just the re labeling.
public NewTestTable(MyColumnObjects[] fields)
{
setModel(new TestObjectTableModel(
new Object [][] {
},
fields
) {
private static final long serialVersionUID = 1L;
public boolean isCellEditable(int rowIndex, int columnIndex) {
[Code]...
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Jul 7, 2014
I have a server with a handful of php services. I communicate with these services by creating connections from java code. The services currently respond with XML, but that can be changed if an alternative way can improve performance.
One of the things I need to do is send varying sized payload (some large) to one of the services. My current plan is to create an xml file in java and perform a POST request with the XML as the payload. I am using an XML because the data is very structured.
From a performance point of view, would it be better to send the XML as a file or just as text? Also, is there a better way to send this data? These services will eventually be used by an android app, where performance and minimizing the size of the data packages will be extremely important.
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Jun 13, 2014
I did this using ArrayList<String> and my tests worked. Meaning I was able to read the strings in a different class through my constructor. However I want to use a string array because it will be easier to handle when I finish the program. I will send each players poker hand in and figure out who is the winner instead of putting it all onto a ArrayList and having to iterate through it. However whenever I did my check I am just printing null.
PokerFile class
void separateHands(String cards) {
//ArrayList<String>playerOne = new ArrayList<String>();
//ArrayList<String>playerTwo = new ArrayList<String>();
String[] playerOne = new String[10];
String[] playerTwo = new String[10];
[Code] .....
ignore the boolean methods I was just building the structure of the program. The print file is what is outputting this:
null
null
null
null
null
null
public class WinningHand extends PokerFile {
//ArrayList<String> p1 = new ArrayList<String>();
//ArrayList<String> p2 = new ArrayList<String>();
String[] p1 = new String[6];
String[] p2 = new String[6];
WinningHand(String[] p1,String[] p2)
[Code] ....
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Dec 23, 2014
New to SMSLib. I checked some samples and docs but did not get any ref/poc wherein I can send SMS with following set-up.
1. I want to send SMS from PC which is connected to internet in office network, where I am using proxy settings to connect to internet.(Basically office PC used in LAN environment)
2. I am not sure how to set the Modem settings in this scenario.
3. What i want - want to test SMS functionality in office environment and would like to send SMS to android based mobile using SMSLib library.
4. I have done SMSLib set-up on my PC and have all the required jars/dlls placed at proper location. So no issues related with set-up. Set-up is on windows platform.
5. I have written sample POC by referring some blogs/SMSLib docs. But as mentioned in points 1 and 2 above, am not getting how to write the code.
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Dec 15, 2014
I am trying send email .So I have downloaded javaEE and javamail jar files and added buildpath.And wrote this code below .But I am getting this exception.
Exception in thread "main" java.lang.RuntimeException: javax.mail.AuthenticationFailedException: 534-5.7.14 <https://accounts.google.com/ContinueSignIn?sarp=1&scc=1&plt=AKgnsbskV
534-5.7.14 ggcPi6MBZ4h8CCyCk2TG9EhiTGyE5MVBv7B3k7DsCldqjCuFvMTQG6aAbatrAWggH29muG
534-5.7.14 dzVh1kUYgMgNHAN558QRCnTjrNtUGv34Ul4pzUaansBuBfB0Kpz6_q7JTbrUuAmlZplouA
534-5.7.14 AHDXpFtuCkd-W17tHrZS5mqgVVxAcuKc-7TkhCDGShnfRBWU2R8v-gfvIQShszqsZmCl0i
[Code] .....
What am i missing here.
public static void main(String[] args) {
final String username = "mymail@gmail.com";
final String password = "mypass";
Properties props = new Properties();
props.put("mail.smtp.auth", "true");
[Code] .....
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Feb 20, 2014
I am new to java (been Reading for 2 days now), and have almost no knowledge on programming (I am a Mechanical Engineer).The problem I have is that I have to upload 5,000 files to a web page (each one is name B001400XXXX.pdf in consecutive order).I have managed to access the web page and select a few form elements using watij, but I am having a hard time sending my pdf file to the server. This is what I have so far:
Java Code:
import org.watij.webspec.dsl.WebSpec;
public class NewClass {
public static void main(String[] args) {
[code]....
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Sep 15, 2014
I need to send a byte array across a network. I know how to do this. (server->client)
byte[] myArray = new byte[]{0,1,2,3,4,5,6,7,8,9};
DataOutputStream.write(myArray);
... and I know how to receive it.
byte[] myArray = new byte[10];
DataInputStream.read(myArray);
When I send over one of these arrays, it ends up stopping storing values in the array when only about half the array is received, even though the array is sent from the server all at once. This results in the receiver's array, in this case, being something like {1,2,3,4,0,0,0,0,0,0}.
I can easily solve this - and already have - by simply adding a loop onto it and waiting for the bytes to all be received, as the method returns the amount of bytes actually read.
byte[] myArray = new byte[10];
int bytesRead = 0;
while( bytesRead < myArray.length) {
bytesRead += DataInputStream.read( myArray, bytesRead, myArray.length - bytesRead );
}
I am simply wondering if there is a better solution to this, as the current solution isn't that elegant. Did I do something wrong to cause only a part of the array to be sent first? Would it be better to use DataInputStream.readByte() to read off the bytes one by one rather than an array at once, and then store them in an array afterward? Would this cause a performance decrease as each byte is read individually? (I'm sending an array of several million bytes)
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Jan 23, 2014
I want to send email from my jsp file .. And I have a html code which contains form and inputs. How can I send the email? And I am using netbeans ..
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