I have a program for a phone directory. It needs to add, delete, append, and edit telephone records. I've gotten it to write and search the files. Just need to get it to delete and edit them.
I have a problem with this application , I have a button that allows users to delete entry's from the array list, but i've noticed when i go back and click display entry's the correct entry has not been deleted.....for example if i enter a,1,2 then b,1,2, then c,1,2 in fields, then delete c,1,2 when i actually go to display the data entered a,1,2 will be gone not the one i entered.
So it seems to be deleting the entry at index 0 of the array list no matter what and not the chosen item..Delete Button Code
private void deleteBtnActionPerformed(java.awt.event.ActionEvent evt) { if (numTf.getText().equals("") || nameTf.getText().equals("") || yearTf.getText().equals("")) { JOptionPane.showMessageDialog(null, "All fields must be full"); } else if (count == 0)
I have a Database with Data of people (name, adress, phone number).
If a user enters a phone number (CLIENT) -> the correct person with the name and adress should appear.
I build up the infrastructure and now I'm at the point that I have to create a Webmethod for it. I just worked on projects like addition of two integers, hello "name", ... I think this example now is harder, BUT i can learn a lot!
The thing is if SITA is the name then I have to insert component to the particular envi tabs , if DEVB is the component I have to insert the component there. How can I do this I have done some code its inserting the data at the bottom og the XML.
So I'm Half way done with this assignment and all I need to is edit and sort my directory. What I've been trying to do as of now is edit my directory. I've tried to use the set function in the Array List, Iterator List etc but I just don't know how implement them mainly because I keep thinking "how can check which variable in the directory the user wants to change(Name, cost etc etc)?".
Main class
Java Code:
package plantnursery; import java.util.Scanner; import java.util.ArrayList; public class PlantNursery { private ArrayList<Plant> plantDirectory = new ArrayList<>(); private static Scanner read = new Scanner(System.in);
I need to check an existence of a file if it is already created or not but the problem is on my code I obviously making the file first before I am able to check if it exist or not.
File createFile = new File ("//path/name.txt");
I've read somewhere that that line should not make a file without the createFile.createNewFile(); but when I tested it and on my program, my program was creating the file even without the .createNewFile() method with that said. I'm confused on how would I be able to check an existence of a file without of course having it pre-created. here is the partial code:
File newFile = new File ("C:/Documents and Settings/Admin/Desktop/Keys.txt"); BufferedWriter write = new BufferedWriter (new FileWriter (newFile)); BufferedReader read = new BufferedReader (new FileReader (newFile));
if (newFile.exist()) { System.out.print("File is existing"); }
Is it possible to edit hosts file in java program? I tried it but I'm getting "AccessDeniedException". I need to have permissions for it, but can i somehow set the permissions in java program for current user?
I am developing a JavaFX application and have succesfully created a tree table with in-line editing. My problem is I am unsure how to check when an object has been changed so I can update the back-end database. According to the TreeTableView API documentation I should register an event handler on each tree table column with event type TreeTableColumn.EDIT_COMMIT_EVENT. Unfortunately I cannot find this constant! I am using JDK 8 update 11.
im new to java and i wanna make a program using java that can add order entries for a restaurant but how to... i was hoping something that would ask to person to input one or two items and before it calculates the total amount to be paid it will ask the guy who inputs the amount whether or not there are additional orders or not before it prints out the total amount... I am pretty sure it will need an if-else statement..
import javax.swing.*; import java.util.Scanner; public class OrderCalc { JFrame.setDefaultLookAndFeelDecorated(true); JFrame aFrame = new JFrame("OrderCalc"); aFrame.setSize(500,250); aFrame.setVisible(true);
I have a web form with a field Department. I want to add Sub Departments(unknown number) of one Department and then further Sub Sub Departments(unknown number) of one Sub Department. How I will make a form and how I will add this data in attached database. I have one solution:
One Department field with a button to add any sub department if any. By clicking on button, a new row will be generated with another text field and new button. In this way, it will go on. Tree like structure.
But I have another solution, JSF Tree to add or delete entries on the run time. But the problem is that I am unable to find any example of JSF tree like structure populated from database and in which we can add or delete entries on run time and on the same time these entries may also be stored in database.
I am trying to build an address book, and I started from what i know how to do.
public class Persona { String nome; String indirizzo; int cellulare; public Persona(String nom, String ind, int cel) { nome = nom; indirizzo = ind; cellulare = cel;
[code].....
Now I would like the program to take a string I insert on command line (for example java Cerca"Robert Baratheon") and compare it to the nome field of every Persona in the address book.
I'm making a project about school management system , i have a jframe to set marks and inside the jframe i have a jtable which is connected to sql database , in the jframe I have a JCombobox with 6 different subjects and in my database i have created 6 tables for the subjects and if any of the subjects are clicked then the jTable will connect to database and change the table to that subject , after it is changed if you double click on any row and insert a value then it will automatically update the table in the database , but my problem is that if I select the first option from the jcombox which is English and edit the values then it works fine , but if I select any other option e.g Math or Science , then I try to edit the table then it edits the English table , I commented the English option in the code to see what happens and I saw that it edits only the first option and if you try to change the subjects and edit than it edits the first subject in the combobox , so how can I solve this ?
I have a database of peoples names linked up to a from to enter a new employee.The form has a previous and next button that should cycle through the employees alphabetically.What im doing the cycle by now is ID which isnt in alphabetical order and just goes by the order they where entered in.
Is there any way to cycle through alphabetically instead? Is running a query each time the next/previous button is pressed the correct way or should it just grab all the names in the array. Theres probably 150 names.
I have an editable JTable that has a lot of JComboBox's as cell entries. I would like to be able to "arrow over" to said cell, and with a pressing of either a numerical button or by typing the first letter of the String selection (possibly followed by a second), be able to select the appropriate selection from the cell's JComboBox. I have tried to add a key listener to the JComboBox itself, which works given that I click on said cell and show its menu.
How would I go about ensuring that, when focus is on the cell itself, and I start typing, the appropriate selection is chosen?? (I think this might get into key binding, but I don't know if I have to try it from the scope of JTable, or from that JTable's TableModel (which I have made my custom version of).
Here is what I have so far (everything but SandwichNumber, SandwichName, and Oregano uses JComboBox): [URL] ...., how would I do such key binding?
I think I'm about 90% complete with this program but I'm stuck on my adding entries method. It gives me a runtime error which says:
Enter the name: Bill Exception in thread "main" java.lang.NullPointerException at Phonebook.addEntry(Phonebook.java:70) at Phonebook.main(Phonebook.java:49)
Here is my code: /* * This program asks the user for input for a name, phone number and notes up * to 200 entries. It stores every contact in a file. Type 'h' for help while * running this program. */ import java.util.Scanner; import java.io.*;
I have an in-cell editable data table with a viewscoped managed bean.I found that the control never goes to the ajax event method onCellEdit when the scope of the bean is @Viewscoped but it works when the scope is changed to request scope.how to get this feature work with viewscope.Below is my code snippet
I found out what my next java class project is, and i am trying to get a head start on it. It is a simple address book. it needs to have 4 choices that get cycled through until quit is chosen:
1. add business contact 2. add personal contact 3. display contacts 4. quit
I have made an abstract contact class with a personal subclass and business subclass(all 3 are required). they have all been made, with set/get methods(the wonders of encapsulation and polymorphism have finally hit home!). The main program needs to add a new subclass object when chosen, and it needs to accept and store contacts by type
So, i am figuring 2 object arraylists for business/personal.
My question is: how do you create an object without having a name for it already programmed? Does it even need to have a unique name, since it would be stored in a seperate index and/or arraylist?
Assignment: Develop a GUI-based program to read the entries of a matrix from a text file. The first number is the number of rows; the second number is the number of columns. The remaining numbers are integers between 1 and 9 in row by row order. Scan the matrix, highlight (display the entries in different color) all cells that form a group of five cells with the same value horizontally, vertically or diagonally.
Example of text(.txt) file: 7 7 3623161 3666669 3936293 3594955 3289867 2493998 1399998
Example of output: 3623161 3666669 3936293 3594955 3289867 2493998 1399998
* ^^this would be what it would look like when displayed in the GUI. But it would be colored. Anything that has 5 in a row ...My Class File:
EX. 0=black(when there is no combo. of 5)1=blue(horizantal combo of 5)2=red(vertical combo of 5)3=green(right diagnol combo of 5)4=purple(left diagol combo of 5)
I have a question about arraylist objects.... I want to create an address book that will contain a persons information (name, phone, address, email..etc..). The first two snippets of code are from the same class ContactArrayList and the last one is from the class Contact. Do I need to create a separate arraylist for each data type? Is it possible to use a single arraylist to contain all the object (person) information and then be searched for using a GUI? I would also like to be able to access this data to be manipulated using a JFrame (add, edit, and search).
public class ContactArrayList<E> implements List<E> { public int size, capacity; E contact; private E[] contacts; public ContactArrayList() { size = 0; capacity = 20;
I have a 2d array that i am manipulating. In my class i have a constructor that takes the dimensions of the array and within th econstructor i need to randomly fill the array. However, when i try to manipulate it in the test program, all that prints out are the default values.
here is the class
import java.util.*; import java.lang.Math; import java.util.Arrays; import java.util.Random; class SummerStats
[Code] .....
And here is the printout
Enter number of rows(people): 3 Enter number of columns(years): 3 Enter number of person to find sum salary: 1 Enter year to find Max salary of that year: 1 [] [] The max salary is at index: (0, 0, ) The largest salary ocurred in year: 0 The sum of person 1 is: 0.0 The total of all salaries is: $0.0 The max salary in year 1 is: 0.0 The average salaries for each year: 0.0, 0.0, 0.0,
The total salary for each person is recorded below.
And the last method called doesn't finish or printout ie the program doesnt end
Why my borrowBook, returnBook, getBookIndex, remove book and printAuthorBook methods wont work. They all have a parameter that is a string and Im guessing its a common problem in all the methods. I think all my code for Book class is right. Iv attached the two classes. I also attached the test library which tests the two classes.
public class Book { // The fields: private String author; private String title; public int pages; public String refNumber; public int numBorrowings; boolean available; // add more fields here
Write an interface Directory to manipulate entries in a telephone directory for the University. The interface must support the following operations:
1) The ability to insert new entries into the directory. Entries should be stored in alphabetical order of surname. 2) Delete entries from the directory either by name or number 3) Provide a lookup method that will find the extension no of a member of staff given his/her name. You should try to make this method run as efficiently as possible. 4) Change a person's telephone number 5) Print the telephone directory in a neatly tabulated fashion.
Write a class ArrayDirectory that implements this interface using an array to store the telephone directory information. The class must store the surname and initial for each member of staff and their telephone extension (a four digit number which may start with a zero). You may find it useful to define a class Entry to store information about individual entries. The entries should be read into the array from a text file consisting of multiple lines in the following format:
Surname<tab>Initials<tab>Telephone extension
Write a main program that reads in data from a file and then tests all the methods of your class interface. Note it is not necessary to write data back to disk (even if it has changed) in this project.
For data insertion and lookup, you should measure the performance for the average case (e.g. looking up a record in the middle of the data). To do this you can use the static method System.currentTimeMillis() which returns the time in milliseconds. To get an accurate measure of the time to perform an operation it is a good idea to perform each operation 1000 (or even 10000) times and measure the time taken. This will remove any problems due to the system clock having a coarse granularity (not ticking very often). Make sure you only time the method and not any input/output associated with it. Your documentation should include a discussion of these results.
Part 2
You decide that your solution to part 1 may be too slow to be useful when used with a real large telephone directory and make the following changes to attempt to improve the performance of your program:
1). Provide a second implementation (ListDirectory) of the Directory interface using the Java Collections List interface and LinkedList classes. 2). The changes in 1) should make adding, deleting and modifying records more efficientbut will probably reduce the time to lookup numbers. To overcome this you use a technique called hashing. Instead of storing all the records on one list you use a series of lists. The data for all people whose surname begins with "A" is stored on the first list, records for all people whose surname begins with "B" on a second list and so on. Write a third implementation (HashDirectory) of the Directory interface using this technique.
Again, you should measure the performance for the best, worst and average cases of implementations 1) and 2) above. Compare the efficiency of each of the 3 implementations in your documentation.
Part 3
Choose one of your 3 implementations from Parts 1 and 2 and embed it in a graphical user interface that allows users to perform all the methods in the Directory interface using a mouse and keyboard appropriately.
I am creating an apointment application. This programm will have the ability to book apointments for a number of different services, such as doctors, hairdressers, teachers etc for a number of cities.
These information will be placed on a combo box and ideally i would like to provide only the options available acording to the choices made so far.
So, for example we have A Pediatric in London A Vet in London A Sergeon in Berlin A Barber in Berlin A Heardresser in Rome A Programmer teacher in London An English teacher in Rome
My thinking is that the user choses the city, for example London, then there will be a type of service combo box. In this case (of London) it will hold Doctors and Teachers. If Doctors is chosen, the next field will hold the available Medical specialty, i.e. Pediatrics and Vets and according to that choice the apropriate doctor will pop up.
My problem is not how to programm that. i havent got there yet.
My problem is how to design it! I am thinking that each individual will be an object. each having the same fields, city, type of service etc. But in such a way i am not sure how i can manage to get all the appropriate information in order to poppulate the combo boxes.
I would have to search all the objects for each combo box? From a rough testing i did, i think i could easily get all the individuals that resign in London, but that would give me two records for the doctors(for example).
