Get Object Strings To Print In List So That User Can Select That Object To Manipulate Its Attributes
Oct 7, 2014
I am new to Java and have read books, the Java docs, and searched the Internet for my problem to no avail. I have an Array of objects that contains strings. How can I get the object's strings to print in a list so that the user can select that object to manipulate its attributes? For example, the user can select "Guitar 1" from a list and manipulate its attributes like tuning it, playing it, etc. I have a class called Instruments and created 10 guitar objects.Here is the code:
Instrument [] guitar = new Instrument[10];
for (int i = 0; i < 10; i++) {
guitar[0] = new Instrument("Guitar 1");
guitar[1] = new Instrument("Guitar 2");
guitar[2] = new Instrument("Guitar 3");
guitar[3] = new Instrument("Guitar 4");
guitar[4] = new Instrument("Guitar 5");
guitar[5] = new Instrument("Guitar 6");
I have an Array of objects that contains strings. I am new to Java and have read books, the Java docs, and searched the Internet for my problem to no avail. How can I get my strings to print in a list so that the user can select an object to manipulate its attributes? I have a class called Instruments and created 10 guitar objects. Here is the code:
Instrument [] guitar = new Instrument[10]; for (int i = 0; i < 10; i++) { guitar[0] = new Instrument("Guitar 1"); guitar[1] = new Instrument("Guitar 2"); guitar[2] = new Instrument("Guitar 3"); guitar[3] = new Instrument("Guitar 4");
I am trying to get this to where I can type in a name and it will search through each object and print back the corresponding object info.
Java Code:
import java.util.Scanner; public class MyPeople { public static void main(String[] args) { Person[] p = new Person[] { new Person("Chris", 26, "Male", "NJ", "Single"), new Person("JoAnna", 23, "Female", "NJ", "Single"), new Person("Dana", 24, "Female", "NJ", "Single"), new Person("Dan", 25, "Male", "NJ", "Single"), new Person("Mike", 31, "Male", "NJ", "Married") };
Task:The main method of the class Things below creates an object called printer deriving from the class PrintingClass and uses that object to print text. Your task is to write the PrintingClass class.
Program to complete: import java.util.Scanner; public class Things { public static void main(String args[]) { String characterString; Scanner reader = new Scanner(System.in); PrintingClass printer = new PrintingClass(); System.out.print("Type in the character string for printing: "); characterString = reader.nextLine(); printer.Print(characterString); } }
// Write the missing class here
Note: In this exercise the solution is part of a conversion unit where many classes have been declared. Because of this the classes are not declared as public using the public attribute.
Example output
Type in the character string for printing: John Doe
John Doe
My Class: class PrintingClass { public void print(){ System.out.println(characterString); } }
I have just started working with linked lists. I have a linked list of Objects and I want to be able to search for a specific object. But currently my code continues to return false. Also how would I go about removing the first index of the linked list.
public static void main(String[] args) { LinkedList<Cookies> ml = new LinkedList<>(); int choice = 0; while (choice >= 0) { choice = menu();
I have two different "business objects", and they have multiple attributes in common(around 25 I believe, all of which are simply a String). Basically, these objects are used for documentation purposes on the same file.
The program can choose to update a given Document at any point in time, even if changes haven't been made to existing version. So what I'm trying to do, is check to see if these attributes differ any between the two files(the exisitng copy, and the new request). If so, I'll update...else I simply throw out the request. The workload can be rather intense at times so I don't want to bog down the system anymore then necessary.
Simply pulling down every attribute for each and comparing seems like a lot of overhead, any more efficient way to achieve these results?
public class BookExamples { String title; String genre; public static void main(String[] args) { // TODO Auto-generated method stub System.out.println("Hey");
[code]...
Eclipse gives me an error for b1.genre = "hey"; saying "Syntax error on token "genre", VariableDeclaratorId expected after this token". I am learning from a HeadFirst Java book that is all in Java 5.0 version which may be part of the problem.
I am trying to have a user select from a printed out array list, instead of having the user type in the "bill type" each time there is a bill to avoid user error as much as possible. For example I would like to have it print out like this:
"Select bill type from list:
1. Rent 2. Car 3. etc..."
and I would like the user to choose a number and not type in the "bill type". I don't want to use "Switch case" because it would need to be an expanding and I don't think "switch case" can do that.
Here is the code:
package homebudget; class Spending { //Do i need a totalAmount variable? String type; double amount; int year, month, day; public Spending()
[Code] ....
case 2: //Give option to enter a new expense or pick from list. //How to do this? If Statement that doesn't list duplicates, or a while search?
resp = JOptionPane.showInputDialog("Enter the type of expense:"); type = resp; resp = JOptionPane.showInputDialog("Enter the amount of the expense:"); amount = Double.parseDouble(resp);
I am having an issue with using FileWriter to print some text to a text file. In the following code, I am supposed to be able to print the initial attributes and the user changed inputs into a file but all I am getting is the memory locations of the objects I created in one long line.
package project3final; import java.io.*; import java.util.*; public class Project3Final { static class Instrument { char [] stringNames = {'E', 'A', 'D', 'G', 'B', 'E'}; private final String instrumentName;
I have some class called sorted to sort the linked list through the nodes of the list. and other class to test this ability, i made object of the sort class called "list1" and insert the values to the linked list.
If i make other object called "list2" and want to merge those two lists by using method merge in sort class. And wrote code of
list1.merge(list2);
How can the merge method in sort class know the values of list1 that called it as this object is created in other class.
I also have this code that takes the file, goes through each line using a loop and counts the total of all the integers on each line, it also then loops and takes each integer on each line and divides it by the total calculated in the previous loop but I don't know what code to manipulate the strings to do these calculations. After these calculations I want to write the updated values to the text file I originally took the data in from. So as an example the total I already for this file to be '232' so the first line would be D 0.06 because 14/232 = 0.06034482758 and rounded to 2 decimal points is 0.06.
Create an equals method that takes an object reference and returns true if the given object equals this object.
Hint: You'll need 'instanceof' and cast to a (Geocache)
So far I have:
public boolean equals(Object O){ if(O instanceof Geocache){ Geocache j=(Geocache) O; if (this.equals(j)) //I know this is wrong... but I can't figure it out return true; }
else return false; }
I think I have it correct up to the casting but I don't understand what I'm suppose to do with the this.equals(). Also I'm getting an error that I'm not returning a boolean... I get this all the time in other problems. I don't get why since I have to instances of returning booleans in this. "returns true if the given object equals this object" makes no sense to me. I assume the given object, in my case, is 'O'. What is 'this' object referring to?
Suppose that you have an ArrayList and that it contains String objects. Which declaration of the ArrayList requires that objects retrieved using the get method be cast to Strings before calling a String method?
I. ArrayList a = new ArrayList(); II. ArrayList<Object> a = new ArrayList<Object>; III. ArrayList<String> a = new ArrayList<String>;
A. I only B. II only C. III only D. I and II only E. I, II, and III
I know that all of these are ways to declare an Array List, but I am unfamiliar with the last two since I usually just declare my Array Lists with the first option.
lst contains list of objects and one of the objects contains the property bDate(Timestamp) which has the value 28-2-1989 00:00:00.0, now I just wants to change the value into 28-2-1989 and store it back into the List as a Timestamp. how can I do that.
I am following those three tutorials and I have completed it with success.
( [URL] .... ) ( [URL] .... ) ( [URL] .... )
But then, as author haven't implemented removeCountries method I tried to create it. What I did initially was to just add to class Countries this method:
public boolean removeCountry(Country country) { return countries.remove(country); }
But although compiler wasn't complaining it didn't work. Actually it worked last night (before reboot) but not today. Must be some SOAP iterator/binding thing or whatever. Or I thought that it worked but in fact it didn't.
Here are original classes:
//------------------------------- public class Country { String CountryId; String CountryName; public Country() { super();
[Code] ....
I would like to avoid my own iterator as JDeveloper can generate automatically iterators for webservices, but if I can't get it that way, what would be better way to write above mentioned iterator in removeCountry method?
Is there any way to remove object directly with something like this:
co.countries.remove(o); co.removeCountry(country)
using method
// This left unused public boolean removeCountry(Country country) { return countries.remove(country); }
I want to create a program where I need to create an object of list type such as text file will contain nos like 1,2,3,4,5 and write into text file and delete the in FIFO order i.e 1,2,3,4,5...how i can achieve to write a program? I tried bt everytime got concurrent modification exception or Array out of bound exception.
I am trying to put a reference to a given subclass object into a linked list, and then come back later, and invoke a method of the subclass object that is in a given spot in the linked list. This produces an error because Object does not have that method. Is it necessary to cast the object to the correct subclass every time I want to use one of its methods, or is there a way to convince the JVM to treat it as always of type MySubclass?
How to use the id parameter in my documents entity to download documents from a list of documents. Normally I use ListDataModel and the getRowData method. I would like to know how to achieve the same thing using an ordinary List object.
My list of documents is called List<CountryDocs> selectedDocs;
Clicking on the download link calls the following method in my managed bean:
@ManagedBean(name = "countryDocBean") @SessionScoped public class CountryDocBean { private List<CountryDocs> selectedDocs; public StreamedContent getDownloadedFile() {
[Code] ....
Debugging shows the value for the id is 0 and this results in a NullPointerException. I've tried several methods for grabbing the document id in my backing bean, but no luck yet. I also read about the the ViewParams and ViewAction method but they caused validation errors to do with the <f:metadata> tags. I don't know how to obtain this value using a normal List object.
Now lets say that I want to access a method 'addInterest()' that is in the 'SavingsAccount' class I would have to do: '((SavingsAccount)s).addInterest();'
The question I have is why do I have to cast 'b' to SavingsAccount? Isn't the actual object reference of 'b' already an instance of 'SavingsAccount' class? How does the 'BankAccount' affect the object itself? I'm really confused as to what class is truly getting instantiated and how BankAccount and SavingsAccount are both functioning to make the object 'b'.
