JavaFX 2.0 :: Predicate Bindings - How To Prevent Rebuilding Them For Each Iteration Of FilteredList
Dec 4, 2014
We're twisting our minds how to use predicate bindings correctly in the real world, i. e. beyond the trivial examples for FilteredList using simply static code but no bindings!
The problem is that our predicate must be bound to a chain of BooleanBindings, of which the final term needs the item injected into the predicate by the FilteredList. Example see purple code:
BooleanBinding a = ...
StringBinding b = ...
ObjectBinding<Predicate> c = Bindings.createObjectBinding(() -> item -> a.or(b.isEqualTo(item.someProperty())).get(), a, b); // Ugly: No "Bindings" style!
myFilteredList.predicateProperty().bind(c);
This code has an ugly smell! It first looks like "Bindings" style, but in fact is plain old lamba mostly! But it also is slow: The code enforces splitting of a and b into separate bindings as it enforces rebuilding the chain a.or(b.isEqualTo(...)) for each single iteration of titem in turn. That induces unnecessarily creating and garbage-collecting Bindings "on the fly", which is not how Bindings are intended -- they shall be created once and simply update their value instead of getting replaced themselves to prevent wasting CPU cycles and keep memory clean.
How to do Predicate Bindings correctly (i. e. without temporarily building Bindings for each "t") ...
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Jun 17, 2014
Is there any way in JavaFX 8 to remove all change/invalidation listeners on an observable? And is there any way to remove all bindings on a property?
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Jun 20, 2014
I have a SplitPane, which is inside another SplitPane in the same tree hierarchy of the Scene. When I set the CSS class of the outer SplitPane, it always overwrites all CSS Settings of the inner one. How can I prevent it, so that e.g. I can assign a red divider for the outer and a green one for the inner SplitPane.
I have defined the CSS with
<code> </code>
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May 14, 2014
I have a TableCell that will hold numbers in a tableview. All is working work nicely, but I want the following behavior:
- when the user begins to edit such a cell, if it doesn't enter a number, the cell will not call commitEdit, but rather display a red border and prevent the user from changing the focus to anything else until he either: enters a correct number or presses ESC.
I don't know how to keep the user in that editting cell if while he has an incorect number. Currently he can click other row/control and he will break the edditing state. I repeat, I don't want the user to be able to click on any row/control until he has a correct number.
Here is my cell implementation:
public class EditableIntegerCell extends TableCell<Person, Integer> {
private TextField textField;
@Override
public void startEdit() {
if (!isEmpty()) {
super.startEdit();
createTextField();
setText(null);
[Code] .....
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Jan 2, 2014
I got Key Bindings for a game I'm working on. They're supposed to move objects when keys are pressed.
(currently, each println(..) represents actual code to move things on the screen, will be added later).
The printing in the console works, but with delays. The words "left", "right", etc. appear with a delay in the console, sometimes half a second delay, sometimes a few seconds delay.
There is no delay at all sometimes, but when a lot of keys are pressed one after the other, there's a delay of several seconds, and only then the words suddenly appear in the console (like the computer had too much to handle at the same time).
When I did the same Key Bindings in a different project without all the game logic, only pressing buttons that print words in the console - it worked perfectly without delay.
So I suspect the problem is something with the game code, or the way I used Key Bindings inside the game code.
I tried putting the Key Bindings code in the thread that contains the game-loop (before the game-loop), and in the constructor. Same problem.
Here is the relevant code of the Board class (extending JPanel), the main JPanel of the game which displays the graphics and manipulates objects.
Java Code:
import java.util.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Board extends JPanel implements Runnable {
Tank tank1,tank2;
boolean[] keysPressed1,keysPressed2;
[Code] ....
As I said, I suspect the program demands too much of the computer, so pressing a lot of keys one after the other, freezes the program for several seconds, and then suddenly prints the words on the console.
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Dec 14, 2014
Is there a way to multiply two single arrays in which the corresponding iteration from one array multiplies with the corresponding iteration from the second array. For example say you have array1[] and array2[]. Each array has a length of 5. Is there a way to multiply array1[0] by array2[0] and array1[1] by array2[1] and so on.... without having to actually write out the equation of array1[0] + array2[0] = someValue for all iterations of the two arrays?
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Oct 6, 2014
I'm writing a program to print an ASCII image using nested for loops. The output is a rocket ship that looks like this.
/**
//**
///**
////**\
/////**\
+=*=*=*=*=*=*+
|../..../..|
|.//..//.|
|//////|
|//////|
|.//..//.|
|../..../..|
+=*=*=*=*=*=*+
|//////|
|.//..//.|
|../..../..|
|../..../..|
|.//..//.|
|//////|
+=*=*=*=*=*=*+
/**
//**
///**
////**\
/////**\
I'm having problems with the mid section of the rocket, specifically the bottom part of the mid section:
|../..../..|
|.//..//.|
|//////|
I'm having difficulty writing the for loop to correctly print the dots. You're supposed to incorporate a constant which allows you to adjust the size of the overall figure. The loop doesn't work when I adjust the size, only when the value of HEIGHT is 3. The loop, however, for some reason works with the top part of the mid section.
This is the for loop for the top section.
for (int dots = 1; dots <= -1 * line + 1 * HEIGHT; dots++) {
System.out.print(".");
}
This is the for loop for the bottom section.
for (int dots = -1 * line + 1 * HEIGHT; dots <= 1; dots++) {
System.out.print(".");
}
Usually reversing the iteration of the loop just requires flipping the conditions, right? But it didn't work this time for some reason. Why this doesn't work? I can post the code to my entire program for compiling.
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Nov 2, 2014
I had to write a foor loop to count the values of a stack of quarters from 1.00 to 3.00 and I had to print the values, that I understood and got it working so I taught the next assignment was going to be easier but I am having a hard time with it. For this one I have to write a for loop to print all the positive integer factors of 144 and I am supposed to print of factor per line but I tried doing that but it doesn't work it just prints out 144.
This is my code. The quarter assignment is also in there because it is part of a lab so just ignore that part since it is working correctly.
public class ForLoopPractice
{
public static void main(String [] args)
{
// Write a for loop to count out the values of a stack of quarters from $1.00 to $3.00
// Print the value of each iteration. Print this all on one line, rounded to the nearest cent.
// To print rounded, use printf, with a placeholder of %.2f
// (%f is the floating-point placeholder; the .2 indicates the number of decimal places)
/* YOUR CODE HERE */
for (double q = 1.00; q <= 3.00; q += .25)
[Code] ....
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Jun 22, 2014
HOW does threading prevent GUI unresponsiveness?
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Jul 25, 2014
How can we prevent SQL Injection in Java Code?..is there any Special cases..
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Jun 29, 2014
I am trying to prevent data from being overwritten and appended instead when I save it to a file. I already set the append boolean to true on the FileOutputStream, but the data is still being overwritten. My code is below:
public class Main {
public static void main(String[] args) {
LinkedHashMultimap<String, Integer> testMap = LinkedHashMultimap.create();
//ListMultimap<String, Integer> test = ArrayListMultimap.create();
OutputStreamWriter outputStream;
testMap.put("NumberA",1);
testMap.put("NumberA", 33);
[Code]...
I performed a print statement to verify that the LinkedHashMultiMap is not replacing values with the same key (which it was not) and realized that the overwriting was occurring when I wrote the data to a file.
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Mar 6, 2014
I just want to ask about a kind inheritance.Let say I have an interface MachineCode.I also have different classes, Binary, Hex and Octal that implements MachineCode
Question: How can I prevent java to create an Object like this:
Binary bin = new Binary();
Hex hex = new Hex();
Octal octal = new Octal();
those declaration above must be compile error,
I want to create Objects of Binary, Hex, and Octal this way:
MachineCode bin = new Binary();
MachineCode hex = new Hex();
MachineCode octal = new Octal();
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Jul 23, 2014
I'm using a BorderLayout, with 26 buttons to make up the alphabet from a keyboard. All the spacing looks great, but when you drag the screen out, everything gets jumbled. I would prefer to have everything stretch out, and keep the same positioning, or everything move towards the center still keeping the keyboard style positioning of the buttons but increasing the size of the window. Will a BorderLayout work for what I want, or should I try something else?
Currently to keep the buttons spaced apart I am keeping there preferred size to 25, and using horizontal and vertical struts to get the buttons positioned like I want.
This is how it is if I keep it the width and height 400, 400.
ex1.jpg
This is what happens when its stretched or shrunk.
ex2.jpg
This is an example of one of the ways I would prefer it
ex4.jpg
This is would also be acceptable.
ex3.jpg
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Apr 29, 2015
import java.util.*;
public class DungeonsAndDragonsRedux {
public static void main(String[] args) {
Scanner s = new Scanner (System.in);
Scanner t = new Scanner (System.in);
t.useDelimiter("\n"); // Prevent scanner from reading code after nextLine().
[code]...
I have this program that is attempting to randomly equip the player with items that are randomly chosen from a list. I don't know how to prevent it from picking the same item twice though. I also don't know how to display the items that haven't been equipped, which is another requirement of this program.
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Oct 8, 2014
Should the piece of code below set prevent the comboBox from being used? All it does at the minute return a null pointer exception. See I am using the same window but I have an if statement so if a condition is true then it will change certain aspects of the window. I want it to be true if it equals export which is does and it's populated fine but when I try and hide it if the condition equals import it returns a null pointer?
comboBoxEnv.setEnabled(false);
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Apr 1, 2014
I have a JSF page (called MainPage) with a commandButton: clicking on it, I open a modal panel with a <Rich:fileUpload> component, related to a listener in corresponding bean.
When I start to upload a file, page MainPage starts to refresh, but I would like to prevent this because it's not necessary.
I tried to "play" with <Rich:fileUpload> property values, but nothing seems to work and I don't know what to do anymore.
Here is file upload component
<rich:fileUpload fileUploadListener="#{pannelloUploadBean.uploadListener}"
id="#{cid}_input"
ajaxSingle="true"
immediateUpload="true"
listHeight="200px"
listWidth="458px">
[Code] .....
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Apr 26, 2015
I am making a very simple 2D array game where the player is asked what size they would like the game board to be. After entering, it displays the board and the player 'P' starts at index [0][0]. After that, they are asked for an action, which can be "up", "down", "left", "right", or "exit". I will be including some extra later (like a treasure at the end, or random obstacles), but for now this is what the game consists of.
I was instructed to "do nothing" when/if the player attempts to go out of bounds. I am trying to simply print an error, such as "Out of bounds! Try again.", then prompt the player again for an action. I even tried to make a boolean method to catch it, but to no avail.
I don't want the exception to occur at all. I just simply want the error message to print to the player and ask for another action. I would prefer not to use try/catch, or try/catch/finally since I already tried that and it still gave the exception error.This program consists of two classes. I will show the class containing the main first, then the client-server type class second.
import java.util.Scanner;
public class Driver {
public static void main(String[] args) {
World world = new World();
boolean keepPlaying;
keepPlaying = true;
boolean isOutOfBounds;
isOutOfBounds = false;
int height = 0;
int width = 0;
int x = 0;
int y = 0;
[code]....
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Jan 12, 2015
If some one add script in my URL, I want the script not pop up, we have tomcat 6 [URL] .....
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Feb 26, 2014
I am generating java script tag and javascript code in servlet and displaying it in each jsp page. i include this in every jsp in my application. I am preparing the following javascript content and diplayin each jsp
<script type="text/javascript"> BOOM.addVar (clientId = SOME universal unique ID ) </script>
the clientid will be uniqueid it gets generated every time.
Here my question is, is there any possibility the clientId will be store in browser cache or third party cache server. if yes how to prevent clientId from cache.
I don't want to prevent the whole jsp file from cache. i just want to prevent only that particular field. so that i can use advantages cache and also prevent particular header field to be cached.
Also can we prevent particular http header attribute from cache.
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Jun 24, 2004
I have a jsp page that generate a hashtable and display its key-value pairs back to the browser. The problem is that it takes on an average about 15 minutes to build this hashtable, and as a result, I always get a timeout error. What can I do to avoid getting the timeout error without changing the server configuration for timeout
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Jun 24, 2014
Tried creating a simple sample but all works as expected.
The following code prevents the cursor from moving when inside a cell of a JTable.
public void keyPressed(KeyEvent e) {
if ( (e.getKeyCode() == KeyEvent.VK_KP_LEFT) || (e.getKeyCode() == KeyEvent.VK_KP_RIGHT)
|| (e.getKeyCode() == KeyEvent.VK_RIGHT) || (e.getKeyCode() == KeyEvent.VK_LEFT) )
{
//Do nothing
e.consume();
}
}
});
When editing a cell, the existing code would use the right/left cursor keys to move from cell to cell as opposed to from character to character when editing a cell. I planned to override the functionality by tossing in the above code as a test to see if it stops the functionality before I override it.
After placing in the above code, the above functionality no longer occurs, but now the cursor moves within the cell as I wanted which is to move from character to character instead of cell to cell. Its great it works, but it really shouldn't. Essentially the default behavior has been restored when it should have really disabled the left/right keys.
I assume there is some underlying class someplace that is doing something to affect the behavior. Since a sample can't be provided I am wondering in what scenarios would the e.consume() restore default functionality?
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Jul 25, 2014
i am developing a web application and uses jsp page to print a payment receipt.
everything works good, but printer scrolls complete sheet after printing first receipt. so need scroll back manually every time i print a receipt.
So, how to stop printer from scrolling entire sheet.
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Aug 14, 2014
I am developing JavaFX application. I have requirement like that javafx application should be always on top. I could not find an option to make it always on top.
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Jan 28, 2014
I know that oracle has released a statement saying that JavaFX will eventually replace Swing. What is the advantage of JavaFX? The new format, using "stage" instead of JFrame, seemed weird. Why is this change necessary? What benefit do we reap from JavaFX that Swing does not have?
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Oct 24, 2014
I am using netbeans scenebuilder and I am a little confused on how I would convert my state capitals java code to a javaFX app.
public class StateCapitals {
Scanner in;
public static void main(String[] args) {
readData();
}
public static void readData() { // Location of file to read
File file = new File("statecapitals.txt");
[code]....
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Oct 21, 2014
I've been on this for a while and for some reason I just can't seem to get this to work. I know my code is solid, but it won't display my image. I've tried swithcing the image to different directories and also using different image sizes and types. I even used Orcale's guide to display your image, but still no go! All I get is a blank canvas? There are no errors. I'm also running NetbeansIDE 8 that supports JavaFX and I made sure the project is a JavaFX Application project.
All I get is a blank new window, but no images.
Here's my code:
package javafxapplication3;
import javafx.application.Application;
import javafx.geometry.Insets;
import javafx.scene.Scene;
import javafx.scene.image.Image;
[code]....
The homework called for me to display it three times - the first one regular, second resized, and the last one rotated. I even deleted the extra images in hope at least one appears.
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