I came across this code today whilst reading Accelerated GWT (Gupta) - page 151.
public static void getListOfBooks(String category, BookStore bookStore) {
serviceInstance.getBooks(category, bookStore.new BookListUpdaterCallback());
}
public static void storeOrder(List books, String userName, BookStore bookStore) {
serviceInstance.storeOrder(books, userName, bookStore.new StoreOrderCallback());
}
What are those new operators doing there? I've never seen such syntax, can anyone explain?
i want to display a image after downloading that image from a web-server
i have wrote the code for downloading the image. but i cant set it up to a label or any thing other than jframe (because i want to add more buttons and labels to the GUI).
here is the code to download the image from the webserver. now i want to set it to a label. please help me
URL url = new URL("http://www.personal.psu.edu/acr117/blogs/audrey/images/image-2.jpg");
image = ImageIO.read(url);
I have an Enum for Days of week (with Everyday, weekend and weekdays) as follows where each entry has an int value.
public enum DaysOfWeek {
Everyday(127),
Weekend(65),
Weekdays(62),
Monday(2),
Tuesday(4),
Wednesday(8),
Thursday(16),
Friday(32),
Saturday(64),
Sunday(1);
private int bitValue;
private DaysOfWeek(int n){
this.bitValue = n;
}
public int getBitValue(){
return this.bitValue;
}
}
Given a TOTAL of any combination of the entries, what would be the simplest way to calculate all individual values and make an arraylist from it. For example given the number 56 (i.e. Wed+Thur+Fri), how to calculate the list of individual values.
For a project, I have to convert a binary string into (an array of) bytes and write it out to a file in binary.
Say that I have a sentence converted into a code string using a huffman encoding. For example, if the sentence was: "hello" h = 00 e = 01, l = 10, o = 11
Then the string representation would be 0001101011.
How would I convert that into a byte? <-- If that question doesn't make sense it's because I know little about bits/byte bitwise shifting and all that has to do with manipulating 1's and 0's.
What are the best practices if you have a class which accepts some parameters but none of them are allowed to be null?
The following is obvious but the exception is a little unspecific:
public class SomeClass
{
public SomeClass(Object one, Object two)
{
if (one == null || two == null)
{
throw new IllegalArgumentException("Parameters can't be null");
}
//...
}
}
Here the exceptions let you know which parameter is null, but the constructor is now pretty ugly:
public class SomeClass
{
public SomeClass(Object one, Object two)
{
if (one == null)
{
throw new IllegalArgumentException("one can't be null");
}
if (two == null)
{
throw new IllegalArgumentException("two can't be null");
}
//...
}
Here the constructor is neater, but now the constructor code isn't really in the constructor:
public class SomeClass
{
public SomeClass(Object one, Object two)
{
setOne(one);
setTwo(two);
}
public void setOne(Object one)
{
if (one == null)
{
throw new IllegalArgumentException("one can't be null");
}
//...
}
public void setTwo(Object two)
{
if (two == null)
{
throw new IllegalArgumentException("two can't be null");
}
//...
}
}
Which of these styles is best? Or is there an alternative which is more widely accepted?
Cheers,
Pete
I am writing a genetic algorithm that approximates an image with a polygon. While going through the different generations, I'd like to output the progress to a JFrame. However, it seems like the JFrame waits until the GA's while loop finishes to display something. I don't believe it's a problem like repainting, since it eventually does display everything once the while loop exits. I want to GUI to update dynamically even when the while loop is running.
Here is my code:
while (some conditions) {
//do some other stuff
gui.displayPolygon(best);
gui.displayFitness(fitness);
gui.setVisible(true);
}
public void displayPolygon(Polygon poly) {
BufferedImage bpoly = ImageProcessor.createImageFromPoly(poly);
ImageProcessor.displayImage(bpoly, polyPanel);
this.setVisible(true);
}
public static void displayImage(BufferedImage bimg, JPanel panel) {
panel.removeAll();
panel.setBounds(0, 0, bimg.getWidth(), bimg.getHeight());
JImagePanel innerPanel = new JImagePanel(bimg, 25, 25);
panel.add(innerPanel);
innerPanel.setLocation(25, 25);
innerPanel.setVisible(true);
panel.setVisible(true);
}
Hey I am trying to shift elements forward sending the last element in the array to data[0]. I did the opposite direction but I can't seem to find my mistake in going in this direction.
Pos is users inputed shift times amount
temp is the temporary holder.
data is the array
if(pos 0)
{
do
{
temp = data[data.length -1];
for(int i =0; i < data.length; i++)
{
if(i == data.length-1)
{
data[0] = temp;
}
else
{
data[i+1] = data[i];
}
}
pos--;
}while(pos > 0);
}
Thanks.
I need to upload a .csv file and save the records in bigtable.
My application successfully parse 200 the records in the csv files and save to table.
Here is my code to save the data.
for (int i=0;i<lines.length -1;i++) //lines hold total records in csv file
{
String line = lines[i];
//The record have 3 columns integer,integer,Text
if(line.length() > 15)
{
int n = line.indexOf(",");
if (n>0)
{
int ID = lInteger.parseInt(ine.substring(0,n));
int n1 = line.indexOf(",", n + 2);
if(n1 > n)
{
int Col1 = Integer.parseInt(line.substring(n + 1, n1));
String Col2 = line.substring(n1 + 1);
myTable uu = new myTable();
uu.setId(ID);
uu.setCol1(MobNo);
Text t = new Text(Col2);
uu.setCol2(t);
PersistenceManager pm = PMF.get().getPersistenceManager();
pm.makePersistent(uu);
pm.close();
}
}
}
}
But when no of records grow it gives timeout error.
The csv file may have upto 800 records.
Is it possible to do that in App-Engine?
(something like batch update)
I have been developing a project and in this project i have designed my code to do the same job after a specified time interval continuously. The job that wanted to be done has a lot of distinct cycles. The interval is small to execute them normally thus i used threads. Until that point everything is clear for me.
To decrease the process and information transaction i wanted to put an session like object that holds the given data and provide it to any thread at anytime. With this object i plan to not query the same configuration information from database at everytime but if it exists on the session take it else query and store on session.
I'm not sure how to implement this structure.
Regards,
I have three integer values. I need to represent these data as a chart. What should i do. Will iReports be the right option. If so give some pointers to tutorials for the IReports.
I came across the following program and it behaving in unexpected manner.
public class ShiftProgram
{
public static void main(String[] args)
{
int i = 0;
while(-1 << i != 0)
i++;
System.out.println(i);
}
}
If we think about this program output, when it reaches 32 while loop condition should return false and terminate and it should print 32.
If you ran this program, it does not print anything but goes into an infinite loop. Any idea whats going on? Thank you in advance.
I am trying to program a game in which I have a Table class and each person sitting at the table is a separate thread. The game involves the people passing tokens around and then stopping when the party chime sounds.
how do i program the run() method so that once I start the person threads, they do not die and are alive until the end of the game
One solution that I tried was having a while (true) {} loop in the run() method but that increases my CPU utilization to around 60-70 percent. Is there a better method?
Hello everyone
Didn't want to bother people in here, but since i am under a time pressure, i am desperate to get help. My questions is how to link the file choosen from a JChooser to a file, and how to converte it to stringm being able to display and edit it in a TextArea.
i hav ethe GUI set up using swing, but the link between actionListener and the Jchooser is not complete
Any help would be much appreciated
code:
http://pastebin.com/p3fb17Wi
Hello,
Which implementation is less "heavy": PriorityQueue or a sorted LinkedList (using a Comparator)?
I want to have all the items sorted. The insertion will be very frequent and ocasionally I will have to run all the list to make some operations.
Thank you!
Based off the one of the demos I have the following code.
Currently what displays in the simulator is just hte contents of the paint function, however the ObjectChoiceField is still selectable if one happens to click in the right location. I would like both the text contents and the paint function contents to appear. Is this possible?
public CityInfoScreen()
{
//invoke the MainScreen constructor
super();
//add a screen title
LabelField title = new LabelField("City Information Kiosk",
LabelField.ELLIPSIS | LabelField.USE_ALL_WIDTH);
setTitle(title);
//add a text label
add(new RichTextField("Major U.S. Cities"));
//add a drop-down list with three choices:
//Los Angeles, Chicago, or New York
//...
String choices[] = {"Los Angeles","Chicago","New York"};
choiceField = new ObjectChoiceField("select a city", choices);
add(choiceField);
Manager man = this.getMainManager();
}
...
public void paint(Graphics g){
super.paint(g);
// g.drawRect(0,left,500,500+left);
g.setGlobalAlpha(0);
g.drawRect(100-left,100-top,200,200);
String text = new Integer(left).toString();
String text2 = new Integer(top).toString();
g.drawText(text + " " + text2,120-left,120-top);
}
I am working on a homework project that should implement a board game between 2 clients over an HttpServlet. I have couple of questions:
1) I read that HttpServlets must be stateless, however, for the sake of the game, I have to keep a lot of state(whose turn it is, the state of the board, etc). Do I have to keep this in the clients? Does the HttpServlet indeed have to be stateless, i.e. have no fields that track state?
2) I know that the clients will talk to the servlet via the doGet/doPost methods, but how can the servlet talk to the clients(for example, if player 1 just made a move and sent it to the servlet, the servlet has to tell client 2 what the move was).
Thank you
Also, if you can point me to a useful, simple example of a similar code online, I would be very grateful
Using series.add(180, 1); produces a perfectly valid chart like this (little red dot at the bottom with some PolarItemRenderer Mods!)
but using series.add(3000/(6000/360), 1); produces this beast:
I assume it's because somewhere, 6000/360 = 16.6... is getting rounded? How can I stop this happening? Thanks :)
Many years ago when I was at uni they said to put a capital i (I) in front of interfaces. Is this still a convention because I see many interfaces that do not follow this.
Creating a JApplet I have 2 Text Fields, a button and a Text Area.
private JPanel addressEntryPanel = new JPanel(new GridLayout(1,3));
private JPanel outputPanel = new JPanel(new GridLayout(1,1));
private JTextField serverTf = new JTextField("");
private JTextField pageTf = new JTextField("");
private JTextArea outputTa = new JTextArea();
private JButton connectBt = new JButton("Connect");
private JScrollPane outputSp = new JScrollPane(outputTa);
public void init()
{
setSize(500,500);
setLayout(new GridLayout(3,1));
add(addressEntryPanel);
addressEntryPanel.add(serverTf);
addressEntryPanel.add(pageTf);
addressEntryPanel.add(connectBt);
addressEntryPanel.setPreferredSize(new Dimension(50,50));
addressEntryPanel.setMaximumSize(addressEntryPanel.getPreferredSize());
addressEntryPanel.setMinimumSize(addressEntryPanel.getPreferredSize());
add(outputPanel);
outputPanel.add(outputSp);
outputTa.setLineWrap(true);
connectBt.addActionListener(this);
The problem is when debugging and putting it in a page the components / panels resize depending on the applet size. I don't want this. I want the textfields to be a certain size, and the text area to be a certain size. I've put stuff in there to set the size of them but they aren't working. How do I go about actually setting a strict size for either the components or the JPanel.
Assign the following 25 scores to a one dimensional int array called "temp"
34,24,78,65,45,100,90,97,56,89,78,98,74,90,98,24,45,76,89,54,12,20,22,55,66
Move the scores to a 2 dimensional int array called "scores" row wise
-- meaning the first 5 scores go into row 0 etc
i have defined a variable inside an if statement and I am trying to access it outside of that if statement now. now the error is saying that it cannot find the symbol which is because its being defined as an intance variable, is there a way i can change it so i can access it outside the variable? heres the code
if((e.getSource()==userOrder2)&& (orderType==1))
{
String buyO= userOrder2.getText();
int buyOrder= Integer.parseInt(buyO); //variable im trying to access
}
// trying to use buyOrder in a different if statement
if(orderType==1 && (stockPrice <= buyOrder))
{
orderResult.setText("The Stock" + (stockName2.getText()) + "was bought at" + stockPrice);
}
What I mean is like servers on video games. You can run an application and it will set up a server on your computer with an IP and a port.
For example, how would you make an application where one host application sets up a thing where it has an IP and a port, and another computer that has access to the internet as well can type in the IP and port and it would be able to communicate with the host? I mean simple communication, like sending a boolean or String.
And would there be any security problems that would be needed to fix?