I am trying to find a concise way to write the sort methods for my class. I am supposed to make a program that can sort objects by a number of fields: year, rank, artist and title.
I used an idea from this thread : java - Sorting a collection of objects - Stack Overflow
And I am trying to use the custom comparator for my sort methods. However for some reason, the sortingBy variable fails to recognize any of the enum types.
Whenever I try to set the sortingBy variable equal to one of them, for example:
Java Code:
private Order sortingBy = Year; mh_sh_highlight_all('java');
I get a "Year cannot be resolved to a variable" error.
What I want to be able to do is make it so every time a specific method is called, say, for example sortTitle(), sortingBy will change to Title, then the SongComparator will sort using the case Title.
Is it possible to do this? I can't figure out how to modify SongComparator's object variables that way.
Java Code:
import java.util.Comparator;
public class SongComparator implements Comparator<Song> {
public enum Order {Year, Rank, Artist, Title}
public Order sortingBy;
I am doing the sorting of multiple fields. This sorting requires to sort the emergency numbers first followed by queue time. However, the sorting is fail, which is the emergency numbers are sorted correctly only but not the queue time. I try to figure out the problem but unfortunately I cannot find where the problem is. Below are the codes for my assignment (Please take note that there is no need to check both ListInterface and LList class) :
public interface ListInterface<T> { public boolean add(T newEntry); public boolean add(int newPosition, T newEntry); public T remove(int givenPosition); public void clear();
[code]....
This is the attachment of the result that I ran earlier:
Capture.jpg
The first list is before sorting while the second list is after sorting.
I am trying to create a method for my "ticketmachine" object that counts ticket objects in an arraylist of "ticket" objects with a specified field "route". The method works if i change the field type of the ticket class to public, however according to the homework task "route" of the ticket class needs to remain a private field.
Here is my code for the method.
public int countTickets(String route) //HAD TO CHANGE Ticket class FIELD "ROUTE" TO PUBLIC!!!! { int index = 0; //returns the number of Ticket objects in the machine with the specified "route". int ticketCounter = 0; while (index < tickets.size())
[Code] ....
Is my general approach to the problem wrong? also is there a way to access a private field?
This program is basically complete. It compiles and runs. It is a college course assignment that I pretty much completed but for the last part in which I'm suppose to change the values of all fields and display the modified values using a toString method. Modifying the values of the fields is where I am stuck. I don't think I need to create a new text data file to do this. The instructor only asked that all the values of fields be changed and this was the last part of the assignment so I don't think it involves creating additional ObjectOutputStream and ObjectInputStream objects. I'm getting a NullPointerException error on line 161.Here is the code. I'm also including the input data file.
//create program so that objects of class can be serialized, implements interface Serialiable //create constructor with 4 parameters with accompanying get and set methods, Override toString method //create text file with 5 records, create Scanner object,ObjectOutputStream, and ObjectInputStream //create new ItemRecord object, change values of all fields in ItemRecord object using object's set methods //modify ItemRecord object using toString method
[hightlight =Java]import java.io.Serializable; public class ItemRecord implements Serializable
----jGRASP wedge2: exit code for process is 1. ----jGRASP: operation complete.
Here is the data file: A100 99.99 10 Canon PowerShot-135 A200 149.99 50 Panasonic-Lumix T55 A300 349.99 20 Nikon- D3200 DSRL A400 280.99 30 Sony- DSC-W800 A500 97.99 20 Samsung- WB35F
Here is the data file for the modified field values. B100 98.00 10 ABC1010 B200 97.00 15 DEF1020 B300 96.00 10 GHI1030 B400 95.00 05 JKL1040 B500 94.00 01 MNO1050
An array has objects with String firstName, String lastName, int ID, char examType('M' or 'F'), and int score. Every object has both Midterm('M') and Final('F'). The array has to be sorted by the first Midterm- 'M' and immediately followed by the Final ('F') of the same person (object). Im having troubles with coming up with a proper algorithm with gettin the Final- 'F' after Midterm for the same person.
Java Code: public static Exam[] collateExams(Exam[] exams) { Exam [] r = new Exam[10]; r = exams; int[] position = new int[10]; int index = 0; for(int i = 0; i < exams.length; i++)
I have to create a method with the following header :
public static <E extends Comparable<E> > void sort ( ArrayList<E> list , int left, int right)
i also had to create a swap cells method and position of max integer method. and also had to read the preserved data file in with a scanner. I implemented the comparable interface I am having difficulty sorting my list by the area. It has to be in descending order.
Geometric Object class: since it has comparator also am interested if i need to change this?
CODE:
Driver: public static void main(String[] args) throws IOException, ClassNotFoundException { Circle c1 = new Circle (4, "red", false); Circle c2 = new Circle (2, "blue", true); Circle c3 = new Circle (10, "blue", true); Rectangle r1 = new Rectangle (10, 6, "yellow", true); Rectangle r2 = new Rectangle ( 5, 11, "green", true); ArrayList <GeometricObject> list = new ArrayList();
I have a school assignment that involves me sorting an array of objects based on one of the class String variables. I am using as the title says a simple selection sort method. The problem I'm having is that when I run the program in debug mode, it never seems to enter the if statement in the inner loop. I would like to say I've tried a number of things to figure it out, but honestly I'm just stumped as to why it's not working.
Here is the code:
public static void sortTransactions(Transaction[] oTransaction){// This is the sorting method, obviously it's not done so it currently just prints to screen. System.out.println("Successful call to sortTransaction()"); String min = ""; int curInd = 0; Transaction[] temp = new Transaction[1];
[Code] ....
The output when I check to see if the array is sorted verifies that the array never does get sorted.
I need to modify modules used in the book that run a bubble sort, selection sort, and insertion sort on an integer array such that each module keeps a count of the number of swaps it makes.
How do I code for this?
Then we have to design an application that uses 3 identical arrays of at least 20 integers. That calls each module on a different array, and display the number swaps made by each algorithm.
how to differ between fields that are not exists to fields that are null? because in my api when someone wants to delete a field he sends null instead of a value. and if he doesnt want to effect this feild he doesnt send it.
I have to organize the rows from the lower to the higher number, the problem is, what I have only organizes the first 3 rows even If I insert 3,4,5...or 10 rows.
for (int i = arg[0].length - 1; i >= 0; i--) { for (int j = 0; j < i ; j++) { for (int k = 0; k < i ; k++) { if (arg[k][j] > arg[k][j + 1]) { int temp = arg[k][j];
Which is the best way to keep track of the number of the objects I've created?Is is a good practice to have a static variable, which will be incremented everytime I call a contructor?
I have application written in rest with Jersey-Jackson for JSON processing. All the resources produce and consume JSON. Now, the problem is, it is a server intensive application and large number of request will be hitting the server with large JSON request object. Now, because of this reason, when the JSON object gets converted in to Java object with String fields in it mapping to JSON request values large number of string objects are getting created which is resulting in frequent GC.
I have a problem with my application. It supposed to store 4 different Room objects but when I entered one only it stores tat object variables into all my Array elements. I just need it to store any number of objects as long as it is less than 4.
Java Code:
import java.util.Arrays; import java.util.Scanner; import javax.swing.JOptionPane; class TestRoom { public static void main(String [] args) { String[] roomsInHouse = new String[4];
Part of my program requires writing a function that determines the number of subsets of k items that can be chosen from a set of n distinct objects ("n choose k" or n!/((n-k)! n!)). The only errors I am getting are from the first line of the function:
// n choose k: distinct subsets of k items chosen from n items public static int choose (int n, int k) { if (k <= 0) return 1; else return choose(n--, k--) * (n/k); }
I am currently working on a project where I need to return data from a database over RMI to a client who requests it. Some of the fields in the Data Object can not be seen by the client so I need to create another object to send over the network instead. The method I use is this...
public static SerializableObject createSerializableObjectFromDataObject(DataObject dataObject){ SerializableObject serializableObject = new SerializableObject(); serializableObject.setField(dataObject.getField()); serializableObject.setAnotherField(dataObject.getAnotherField()); return serializableObject; }
Is there a better way of doing this? I am creating many subclasses DataObject which all require this static method to be implemented and I can't push it into the superclass because each one needs custom behaviour.
This is the link [URL] and it says One significant difference between classes and interfaces is that classes can have fields whereas interfaces cannot.How can this be possible?
At the end of my main method, I want it to print out the input given that should have been stored in my sandwich class fields, but it didn't.
import java.util.*; import java.lang.*; public class SandwichBuilder { public static void main(String[] args) { Scanner inputDevice = new Scanner(System.in);
I am unsure of something. In the following class, which is read first; the static field or the main method?
class Test{ static int a = 3; public static void main(String args []) { //some code} }
I put some code in Eclipse and have tried to look at the hierarchy. It would point to all static fields being initialized in order from top to bottom, including the main method.I had thought that the main method was always the first thing in a public class to be initialized, regardless of where in the code it resides. Am I reading the Eclipse hierarchy wrong? I find Eclipse very difficult, especially since I typically code in Textmate. I just want to see how my code is operated upon,
If I define a class which contains a few static fields, and then have a few classes who inherit this class, then all these classes would have the static field as well. Now my question is the following: would all those sub classes (and the base class itself) share the same object, or would each class have one object for all it's instances?
I have a simple class, called InputManager, which has methods that communicate with another class DatabaseManager which has access to Database which is actually object that contains information about actual database.
My JFrame has Navigation class (extends JPanel). There I put all needed JButtons, JLists and so on.. This class has instance of InputManager and when user interacts with GUI components inside of it, Navigation calls InputManager methods, it then analyses the call and calls needed methods on DeviceManager, which then sends queries to Database and etc.
The problem is, that at the beginning (when user runs a program), I want to get information (which is actually values for my GUI components ) from Database. It could, for example, create another DatabaseManager and connect to the Database to get information, but it is okay to have two objects?
I was also thinking about sending same DatabaseManager object through InputManager to Navigation, but it seems strange for me to have two objects, which can interact with each other in both directions(Class A has instance of Class B, and Class B has instance of Class A). Is there anything bad this can do?
Also what I noticed that it seems odd that GUI class would have to get information from database. (Logic in GUI class).
I have a button in which I need to do the following:
After I click it It reads the values given in a jtextfield1 and in the other jtextfields I need it to settext in them from the database I mean if I have for example id=1 when I click the button it goes to the database and find the id 1 then write the infos in the other textfields
i need to seek all data in result set one by one.i excuted a query which i don't know the result of it...it could be have one result in result set or 10 result.i tested this code :
PHP Code:
Query = "select * from book" while (Rs.next)) { row.add(new Book(Rs.getString(i)));
//Book is a class
}
but didn't work. do we have any other way we seek the result set without rs.next() ???
I have a web application. I want to generate the UI part(basically html/jsp pages) to be generated dynamically using drag and drop of elements.So is there is any way that I can:
1: Have drag and drop of elements in jsps? 2: How I can create and store back the form attributes dynamically?
