JSF :: Primefaces Live Scrolling Taking Long Time With Large Dataset
Feb 21, 2014
I have a primefaces datatable with about 52000 records to be fetched.Since it is a large dataset,i tried using live scrolling feature of primefaces with scroll rows equal to 20.THe number of columns is 53.The table also has filtering and sorting feature on its each column.Still i am not satisfied with the performance of the table.It takes about 15 secs for the page to load,worst thing is that it takes about 65 secs for the next set of 20 records to be loaded on reaching the end of scrolling.
Just for testing i reduced the total number of records to 25000 and the preformance improves with scroll time of 29 secs.I am really not able to understand why it is taking this much time when i am displaying only 20 records at a time.The total number of records should not have affected the performance.
I have datatable with live scrolling enabled.The columns are not getting sorted fully.When one of the columns is sorted,for example "insured" in the image shown below, all the records seem to have sorted but when i reach the end of scroll and next set of records get loaded i see other records in unsorted order as indicated in the image ,when i try to see the column in descending order.So because of this i am not getting the sorting feature accurately done(All records are not getting sorted at a single stretch)
I've been tasked with processing a large dataset as part of a class assignment. One of the fields is a 24-digit unsigned hex number. I realized that, rather than storing the field verbatim in a char array of length 24, I could store the actual value of the hex number in an array only 6 chars long (I chose char over int because chars are unsigned). To do this, I wrote the following simple class to accept the hex string and convert it so that it can be stored in that manner:
private class Hex24 { private final char[] hexAsInt = new char[6]; public Hex24(String h) { for(int index = 0; index < 6; ++index) hexAsInt[index] = (char)Integer.parseUnsignedInt(h.substring(index * 4, (index + 1) * 4));
[Code] ....
Assuming all this works (haven't tested it, but I think it should), what I'm wondering is how much memory this will save me (if any) compared to just throwing everything into a char[24] array. The underlying char[6] is obviously quite a bit smaller, but objects must take up more space than just their fields since Java needs to know what kind of object it is so it can know what methods it has, etc..How to accurately compare the size of a Hex24 object to the size of a 24 character array.
I guess another option/thing I might want to compare size efficiency for is putting the char[6] along with the conversion/comparison logic directly into the classes (as fields/member methods) where I'm currently using Hex24 fields. I'd guess this is the most memory-efficient option I've come up with, but it would lead to a lot of code duplication.
Another thing I'd like to compare is the size of a String vs. the size of the equivalent char array for shortish text fields. If this difference is big enough it might be worth storing those fields as arrays rather than Strings.
I've built up an unreasonably large and unreasonably complicated JPanel. Unfortunately, when I use setViewportView to add it to a JScrollPane, a get an extended UI freeze—that operation takes several seconds. I'm trying to figure out what's taking so long. I've tried some fairly extreme things, like overriding the paintComponent, PaintComponents, paintChildren, paint, repaint, validate, revalidate, and validateTree methods in the panel with no-ops to try to figure out what's taking so long, but to no avail. I've tried validating the JPanel before adding it, but that has no effect. If I override the addImpl method of the scroll pane, that makes things quick, but it doesn't really narrow things down much.
I am working on a web-application where i have a functionality which generates reports based on the data from DB. for small amount of data its working nice if the data is huge its taking more time. to avoid this problem i developed a standalone batch where i generated the jar file for the sources in web-application and made a call to the appropriate methods.
But my problem is if web-application takes 10 secs to generate the report but in the case of standalone its taking nearly 3-5 mins to generate the same report. i didn't do much of the changes in code just using the same code as web-application
I am using tomcat 6 application server to run the web-application for standalone using batch commands.....
I am trying to take a password then generate two characters to keep in the password dataset. So far I have this going but keep having minor issues. For one how come it won't allow me to use List.length?
/*Code/*
import java.util.Scanner; public class Project{ public static void main(String[] args){ System.out.println("Enter the password:"); }
I am developing some application in Java. The need is to continuously do a video streaming in the software. I am new to this and want to know how to do it.
I was testing my JavaFX2.2.7 based media player code in a current Java 6 application when I discovered that HTTP Live Streaming does not seem to work. I can play a local file of the supported format (Sintel trailor mp4 h264) but when I try and use an HTTP Live Stream instead, nothing plays. (for example [URL] ). I end up with a blank player, and no exceptions or errors.
private static final String MEDIA_URL = "http://download.oracle.com/otndocs/products/javafx/JavaRap/prog_index.m3u8"; Media media = new Media(MEDIA_URL); MediaException ex = media.getError(); if (ex != null){ System.out.println("Media Error" + ex.getMessage()); } else{ System.out.println("No Media Error"); }
Program console output: "No Media Error"
I thought it was something wrong with my player code, so as a last resort, I went to JavaFX 2 - Ensemble and copied the source and put it directly into my application and ran it... Unfortunately the same result occurs. The player runs, but simply shows a blank video window. The controls are available, but no video plays.
Based on the Release notes for Java 2.2.7 I was under the impression that HLS was supported. Am I incorrect? I cannot upgrade to Java 7 as I am firmly stuck with Java 1.6.0.32 due to project constraints.
Whenever i perform any operation in my application Live Bytes of a particular Instance of a class increases by 1000.Although i perform the same operation everytime it always increases by 100 or 1000.Is this a memory leak or does these instances increase everytime we perform an operation.
This piece of code is giving me the most trouble as I cannot convert the self defined class (Fraction) into int in order to store the elements in the variable (max). What is the best way to go about grabbing the next element and storing it in max and compare it to the previous to get the highest and lowest value?
System.out.println("Enter numerator / denominator"); frak[0] = new Fraction(keyb.nextInt(), keyb.nextInt()); frak[0] = max; for (int i = 1; i < frak.length; i++){ // starting from array element 1 System.out.println("Enter numerator / denominator"); frak[i] = new Fraction(keyb.nextInt(), keyb.nextInt()); if (max > frak[i]){ }
I have written a java app that's been working for a few years now and the client is very satisfied. However, a certain user has been experiencing a problem where the app runs fine BUT whenever it interacts with the OS (Win7 in this case), it takes ~10 mins to respond. Actions include, for example, exporting the currently displayed JTable to a CSV file or making an OS call to open up MS Word, etc.
I copied the users version of the app onto my platform (win 8.1) and tested it on winXP too with no problems which points towards an issue on the users particular PC. Furthermore, it used to run on the users PC fine until something (??) happened.
I've tried the following so far:-
1. looked at System restore to check anything new installed - nothing obvious 2. disabling anti virus - problem still occurs 3. monitoring JVM process time using Task Manager - little CPU time seems to be utilised (=> no loop etc)
I'll try :-
1. using JvisualVM - although I don't think this will show me what's going on with the OS 2. excluding the JVM and the app from all anti malware
Any app or something that shows interaction with the OS so I can trace what might be intercepting the call from my app to the OS?
I have a small bug in my program. The user is asked what person(s) information they want to access but lets say they want captain they must enter "captain" twice. I think it will make more sense to you with the code. I have searched all over to see what is causing the bug but still have found no resolution. I even tried making two different scanners but that didn't work either.
I know the while loop (line 16) I am using is causing the bug because it works fine without that but then I cannot validate the input.
package myproject; import java.util.Scanner; public class Enterprise { public static void main (String[]args){ String userInput;
What I have so far are two classes, Movie class and MovieTestDrive class. I've to get the title, genre and ratings for movies and then put them into an array and call the playIt() method.
I would like to create a for loop to iterate three times for three instances of the Movie class but I don't know how to do it.
When I try to run the code, it won't work and I don't know if this is because I have Scanner running incorrectly whilst encapsulating my data. What I have so far:
class Movie { // Create instance variables for the Movie class. private String title; private String genre; private int rating; // Use getters and setters to set and display the variables.
This is the code that I have so far, It will only print out the digit if it is entered first..How to I get it to print out all digits? and I am getting an error that the c is not initialized
import java.util.*; //Write a program that prompts the user for some text. Output only the digits in that text. Hint: Use a loop and the Character.isDigit method. public class Q1 {
I've got a panel which an arbitrary number of text fields may be added to at run time. I've got it set up so that the window's height, and the height of the panel in which the fields appear will never exceed the height of the screen.What I don't have is a way to make the panel scroll to access the fields that are being visually truncated. I'm setting the autoscrolls on the panel to true, but when I run the program, the fields are simply truncated.
I am making a table that is dynamically made but it isn't working with scroll bars. The scroll bars show but don't work. Here is the code:
JPanel pList = new JPanel(); Component pListl = new JLabel("Here you can view and search for players."); pList.add(pListl); tabbedPane.addTab("Player List",pList); tabbedPane.setMnemonicAt(0,KeyEvent.VK_1);
[Code] ....
Yes I am spamming entries into the result object, this is so I can test the scrolling as right now I don't have enough data for overflowing entries but will do soon.
I am working on an assignment that I can't seem to figure out the final part to. The program takes in course data such as the time the class starts and how long it lasts. The time is in military time (0000 - 2400)
I need the output time to be the time the class started, plus the length of the class, and displayed in military time.
I can't for the life of me figure out how to do this. I have gotten a program that works for this time and minutes, and displays the correct 1020. But when I change the information to say
Start time: 0700 Length = 90 minutes
I get:
Endtime = 90
90 is technically correct, the way the formula is setup, but I need it to display 0900 not 90.
Here is the code that I have. Be easy, I'm still learning, and this is just the file I created to get the formula to work. Also, the verbose in here is just for my own debugging to make sure values should be what I'm expecting them to be.
public class calc { public static void main(String[] args) { double hours, minutes, length; double temp; int time = 2400; hours = time / 100; System.out.println("Hours are: " + hours);
I am stumped on a coding project I am working on. I am making an inventory program with predefined values for the items. I am not sure how to iterate through my arrayList, and allow the user to input the "number sold."
I have made an arrayList and populated it using the add(), but I am not sure if it is working correctly. This is my inventoryItem class :
package inventory; import java.text.DecimalFormat; public class inventoryItm { String itemName; double unitPrice; int numberSold;
There is a problem that I am facing while using the Scanner class for taking inputs from the user. Suppose if I need to take an integer and a String input from the user, and I take the integer input first then the place where the user has to input the String skips and the variable shows a "" nothing on printing it. Suppose in this code snippet
import java.util.Scanner; public class Test { public static void main(String[] args) { Scanner sc = new Scanner(System.in); System.out.println("Enter a number"); int n = sc.nextInt(); System.out.println("Enter a word"); String str = sc.nextLine(); System.out.println("Enter integer is " + n); System.out.println("Entered statement is " + str); } }
The output is Enter a number 13 Enter a word Enter integer is 13 Entered statement is
I need to know why this happens and how should I avoid it. I've seen that taking the String input first solves the issue but while taking the input in a loop to populate a database the program only lets the user enter the first statement and the following statements are skipped.
I've looking for information on taking a range of data from a google sheet such as the one below.
JavaGroupCat.png
The function that i'm trying to accomplish is allowing a user to run the program and input their 5-digit Unique - ID. After inputting their 5-Digit ID the program will take that input, and check whether or not that ID is present on the spreadsheet.
Ex: (Using the numbers from above) I type in : "89504" then (I would want the program to spit out if the ID is on the sheet). (89504 appears on the sheet) So i would want it to print out something like "ID is found on list "Cat". Associated named include: "Phil Roberts".
I tried, with my limited knowledge, to create what I have described above.
import java.io.*; import java.util.*; public class SwitchesTwo { public static void main(String args[]) { System.out.println("Welcome to the ID # Checker"); System.out.println("Enter the ID of the person you are trying to verify");
[Code].....
The issue I have with the mock-up above is the fact that I have to manually add in every individual name and ID. I would much rather write code that would allow it to update as I update the spreadsheet. Therefore, no need for 800+ cases. (theres around 800 ID numbers for this project)
In a perfect world, the code would be something like "Take info from cells C5 - C2000 and store as string array" (I think array would work.) while also doing the same with B5 - B2000.
I am not very comfortable with Strings in Java. The problem I am facing is, taking a string that contains a sentence and reversing the words. Example would be, "Hi I am Bob" and changing it to "Bob am I Hi". Then returning the String.
My initial thoughts were to change the string into a character array and then manually doing the work with loops and tedious comparison statements. I quickly realized that there must be a better way but I am not very familiar with strings in Java to know what a more sufficient way would be.
I am trying to create a JScrollPane with buttons in it, but I noticed that when I try to scroll, the items all move into ONE row at the top of the JScrollPane. How do I have them vertical? Is there something wrong with the way I am setting up the JScrollPane?
i am trying to make a platform game in java and to do this im trying to make a scrolling bacground. i can get the background image to scroll. However, i cant get the image to scroll forever, here is the code.
GamePanel class ( the jpanel ) public class GamePanel extends JPanel implements ActionListener{ static ArrayList<BackGround> store = new ArrayList<BackGround>(); public GamePanel(){ setFocusable(true); Timer time = new Timer(5,this); time.start(); store.add(new BackGround(0,-200));
the problem i have is that i want the bacground to loop. however, once the first instance of the background is done scrolling it freezes and doesnt load anymore. here is the code for adding a new background to the list
I have Implemented a user control / component that allows zooming in and out of a displayed BufferedImage, for discussion's sake, 3rd party libraries are excluded and everything must be from scratch.I have an image rendered on a JPanel, the JPanel is contained within a scrollbar.
Zooming inout etc works perfectly.The Scrollbars are rendered correctly on Zoom In and disappear when I zoom out.I want to add the functionality of focusing on a specific quarter of the displayed image via four dedicated buttons, each send an int (1-4) to a method, that controls the scrollbars.
And resizes the image whilst scrolling the scrollbars accordingly,The method works as expected, and the scrollbars go to the desired location, But there's a catch:The first click on any of the above buttons does not work, but from the second click and on, everything works great!
