And in the server getCustomerList() accessed to database, how many times getCustomerList() would be called from I request the xhtml page?. I have read this would be called several times because of JSF internals and It would be better to store it in a variable and access this variable.
1. Is this true this would be called several times? why?
2. If the previous statement was true, how to avoid it, I mean not call the method from a service?
When i access to this page and save it as xml in realtime, the tags in xml file saved is empty while it is initialized and everything is working properly.
<edges> </edges>
How can i access to content of this xhtml page and save it on disk?
I am new to JSF and when i try to implement a sample application im getting this wierd error of page not found(.xhtml). Here is the code i have created..
Bean class :
package com.trail.beans; import javax.faces.bean.ManagedBean; import javax.faces.bean.SessionScoped; @ManagedBean @SessionScoped public class UserLoginBean {
My project consists of a web app where a user can select a area from a picture and f.e. if it is a office layout he can input the worker name and any peace of hardware that the area might have. In this case there are two categories: Hardware and Computer. Hardware - it has 5 dropdown lists consisting of printer, scanner and etc. Computer - like Hardware consists of many dropdown lists which add up to components such as processor, motherboard and etc. For me, considering this is my first ever web app project, is a huge step towards web development, I have used various mixes of Java, javascript and primefaces code.
My current problem: When a user selects an area he gets a dialog box where he is prompted to select his desired input, afterwards the user clicks the 'save' button and get's another dialogbox which has a resume of what he has selected so he could check out his input and save it by clicking the 'save' button in the resume box. My problem is that when the user clicks the save button the button calls a method which takes all the input and creates an Area object (Area object consists of various objects such as: Coordinates, Dimensions, Employee, ComputerList and HardwareList) and sends a query to the database, but all the values I get is null.
XHTML code:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xmlns:ui="http://java.sun.com/jsf/facelets" xmlns:h="http://java.sun.com/jsf/html" xmlns:f="http://java.sun.com/jsf/core" xmlns:p="http://primefaces.org/ui">
I have this program, I am wondering if it is possible to call files from the main method and sort them into my saveOneRocord method? If so, how would that look?
I want to call a servlet variable in jsp page textfields.Actually in servlet I fetch a jasper report properties in servlet variables and then this variable call from jsp page and after changing properties values this report saved.my servlet code is:
so how to fetch servlet variable from jsp page textfields on load page and after edit that values then again save this values in jasper report on save button.
how come you can call non static methods from other classes(objects when they are created from main) but not static methods in the same class as the main method??
example I cannot call the method maximum from the main method aslong as its not static BUT i can call other objects non static methods from main??
class test{ public static void main(String [] args){ Scanner input = new Scanner(System.in); //create new Scanner object //for input int number1; int number2;
Life Cycle Call back methods(init(), destroy(),...) are not transactional by default and expecting this in coming EJB releases (EJB 3.x / EJB 4.x). I was expecting next EJB release along with Java 8, but it stays at 3.2
I am trying to make a 2d graphical animation using the java swing classes in order to make a frame. I had a basic version working when all of the code was under the main method, but when I moved some into another method it broke it. With y understanding of java my code should work as I create a variable of the method containing the code and then assign the size and exit button. However this causes many problems such as my BeaconFrame method informing me that it is unused when I have used it. Here is my code:
import javax.swing.*; import java.awt.*; public class BelishaBeacon { public void BeaconFrame() { JFrame frame = new JFrame(); JPanel panel1 = new JPanel();
I'm making a java program that can "convert" java to arduino by sending commands over a serial port. I'm using the JSSC library, and using methods to shorten things up a bit.
I've already made the code that starts up the serial port and it does connect. But I've made two different classes for the methods. One for the RXTX and one for the Arduino.
Do inherited methods use their instance variables or do they use the ones in the method that inherits them?
For example, Class B extends Class A. Class A and B both have the instance variable "potato". A client program tries to use method "cut" using an object of Class B, but class B has no cut method. So, class B uses the "cut" method inherited from class A. What I want to know is will that cut class A's potato or class B's?
i'm trying to modify and use a GUI to set the variables the setter methods. while the code seems valid to me and should work perfectly, i get ArrayIndexOutOfBounds and StringIndexOutOfBounds and respectively lines 111 and 134. i'm am not the original author of this code, all i want is to get it to work fine.
I have a question about a method I have. In my game, I had a move method to move my player left and right, and originally this method was huge, as it also took care checking collisions and a few other things. I broke it up a bit and put the collisions in their own methods and call them from again another method... Here is an extract which I hope illustrates my point:
private static final double MOVE_SPEED = 0.2; private static final double MAX_MOVE_SPEED = 3.5; private static final double STOP_SPEED = 0.18; private double xPos; private double yPos;
[Code] .....
Something I thought might be a good idea is to check the direction collision when im doing the calculations for that direction:
Then I thought instead i can check it after both of these steps:
if(moveLeft || dx < 0.0) { checkLeft(); }
I guess my question is quite general: How much is acceptable to break up a method? How many chains of method calls is acceptable? Is it ok to call the same method from different nearby places?
i need to change my code in order to stop the member variables from being directly altered and its been suggested that i should use a setter and getter method. Ive read up about these and im still unsure at how they should be implemented into my code for my project.
so, i was reading my java book and learning about objects and methods and it starts talking about Encapsulation and mentions that it's good practice to set instance variables as private and instead of accessing the instance variables directly, we should create a set method and get method to get and set the stuff we want to pass to the class containing the object...
for example, in this class, we're passing the integer 70 for object dog one and integer 8 for object dog two for the dog class... and these these 2 integers are sent to the setsize method so we're not accessing instance variable size directly.
i dont quite get it though....if we the programmer are the one deciding what size the integer is for the dog, and the setsize method takes the one.setSize(70) or (8) and puts them in setsize(int s) as s... but only to copy that integer stored in s back to private int size.... why do we even need to bother with making these two extra methods such as setSize, getSize?
in the book it says that... well what if the code gets into the wrong hand and someone writes something like one.setSize(0) then you would get a dog with size 0 which is essentially illogical. but then again, i'm the programmer, and i am the person who writes the code and passing the right integer.The reason for public and private... that part i understand... i can see why if a variable's data can get changed amidst the code during calculations and you dont want it to directly change the original variable and have it mess up the code, but this code from the book just a bad example of demonstrating the reason? since we manually pass the information ourselves and passing it to method setSize... and all setSize does is stores it in another integer, only to copy it right away to size (which is the original private variable we were tryign to protect?
Any simple code to demonstrate how the code might end up changing an instance variable and why we would want to protect it by using private?
class GoodDog { private int size; public int getSize() { return size; } public void setSize(int s) { size = s;
For reference I am programming Java in BlueJ. I am fairly new to the language and I am having trouble with sorting.
I am trying to call / test all of the 5 sorting methods (at the same time) in the main class. To be specific, the sorted list has to technically outputted 5 times.
I figured out how to call / test Quicksort:
Sorting.quickSort(friends, 0, friends.length-1);
But the others are not working correctly. Specifically these:
For reference, this is the output when it is not sorted:
Smith, John 610-555-7384 Barnes, Sarah215-555-3827 Riley, Mark 733-555-2969 Getz, Laura 663-555-3984 Smith, Larry464-555-3489 Phelps, Frank322-555-2284 Grant, Marsha243-555-2837
This is the output when it is sorted:
Barnes, Sarah215-555-3827 Getz, Laura 663-555-3984 Grant, Marsha243-555-2837 Phelps, Frank322-555-2284 Riley, Mark 733-555-2969 Smith, John 610-555-7384 Smith, Larry464-555-3489
This is the class Sorting, which I should note is all correct:
public class Sorting{ /** * Swaps to elements in an array. Used by various sorting algorithms. * * @param data the array in which the elements are swapped * @param index1 the index of the first element to be swapped * @param index2 the index of the second element to be swapped */ private static <T extends Comparable<? super T>> void swap(T[] data, int index1, int index2){ T temp = data[index1]; data[index1] = data[index2];
[Code]...
This is the Main class in which I am supposed to call the sorting methods, SortPhoneList:
public class SortPhoneList{ /** * Creates an array of Contact objects, sorts them, then prints * them. */ public static void main (String[] args){ Contact[] friends = new Contact[7]; friends[0] = new Contact ("John", "Smith", "610-555-7384"); friends[1] = new Contact ("Sarah", "Barnes", "215-555-3827");
I thought static methods could never use instance variables, because they wouldn't know which instance to look at.
From Head First Java, p. 284: "A static method is not associated with a particular instance - only the class - so it cannot access any instance variable values of its class. It wouldn't know which instance's values to use."
Now I was answering some mock exam questions from Cameron McKenzie's SCJA book, and I don't understand one of the options. On page 205, the last question has an option that says: "Instance variables ... are not visible in static methods, unless passed in as arguments." This option is supposed to be correct. Now... how does that work?
a. Create an application named ArithmeticMethods whose main() method holds two integer variables. Assign values to the variables. In turn, pass each value to methods named displayNumberPlus10(), displayNumberPlus100(), and displayNumberPlus1000(). Create each method to perform the task its name implies.
b. Modify the ArithmeticMethods class to accept the values of the two integers from a user at the keyboard.
I'm new to JSP but I've to use it to grab data coming from an external site, pass data to a Bean, write data in a DB and redirect the user to another page. Follow the JSP page.
<%@page import="EJB.getResponse"%> <% long paymentID = Long.parseLong(request.getParameter("paymentid")); String responsecode = "9999"; getResponse g = new getResponse();
[Code] ....
This is the bean:
@ManagedBean @RequestScoped public class getResponse implements Serializable { private Long paymentId; private String result; private String auth;
[Code] ....
On the console I see the prints but I receive the NullPointerException
WARNING: StandardWrapperValve[jsp]: PWC1406: Servlet.service() for servlet jsp threw exception java.lang.NullPointerException at EJB.getResponse.printData(getResponse.java:72) at org.apache.jsp.notify_jsp._jspService(notify_jsp.java from :60) at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:111)
I am trying to pass an object of type Product p to my editProduct method, however trying to call p.getName(); doesn't work and throws a NullPointerException. The same kind of thing works for my displayRecord method (in a different class) and I can call .getName() on Product p, also passed as an argument to that method. Below is my editProduct class. The NullPointerExcepion is being thrown at line 61 (i.e., nameField.setText(p.getName());).
I don't know if I explained right, so here's a line thing of how the classes relate:
And as a side note: adding the line p = new Product(); fixes it and successfully runs the class (including the Save and Quit parts) but obviously I want it to specifically refer to the Product I pass to the method.
I'm asking a question because I don't understand how Product p could possibly be null, because the argument is passed through my DisplayRecord class, which also takes a Product p argument and works. In that class, I have declared Product prod = p; and prod is what I am passing to editProduct.
If i try to make it public void than it say can't call non-static methods inside static(main).if i try to put it into new class and then call it after i fail input it goes into infinite loop.
In Main.java, How can i call method in CircleCalculationMethod.java ?
Should I put everything in same folder ??Should i do something like "import CircleCalculationMethod.java"Should i do something like create a package ...
