Cannot Assign Cloned String Array To Generic Type Array
Jun 21, 2014
I have the following code in which I am looping through the rows of one array (composed of Strings) and copying it to another array. I am using .clone() to achieve this and it seems work as it changes the memory location of the rows themselves. I did notice that the String objects are still pointing to the same location in memory in both arrays but I won't worry about that for now, at the moment I just want to understand why the array I am cloning is not successfully assigning to the other array.
This is the incorrect line: ar[r] = maze[r].clone();
public class CollisionManager<T> { private boolean collision = false; private T mainEntity; public <T extends Entities> void handleCollision(T mainEntity, T secondEntity){ this.mainEntity = mainEntity; // This is illegal. } }
Why "this.mainEntity = mainEntity" is incorrect and also show me the correct way to achieve this?
The error I am getting is "Type mismatch: cannot convert T to T"
So I have this stack. I'm writing out all the operations and what not but I'm having trouble bypassing this "generic array creation" problem. I'm meant to be creating an array based implementation of a stack and from my research from google and my various attempts at things, I have not found a solution that works.
In addition; I have all the operations written that I need except for one final one. And that is clear(). clear() is meant to empty the array, essentially it is a popAll() method. Then all I need to do is set up so I can print out the arrays and I should be able to handle everything else.
StackInterface:
/** An interface for the ADT stack. */ public interface StackInterface<T> { /** Adds a new entry to the top of this stack. @param newEntry an object to be added to the stack */ public void push(T newEntry);
/** Removes and returns this stackÕs top entry. @return either the object at the top of the stack or, if the stack is empty before the operation, null */ public T pop();
I have learn that every function in java is treated as a normal function including main() except that execution of a program starts here. I tried to overload it.
But I am getting error while doing so via String type array as an argument of main.
class Hello { public static void main() { System.out.println("Hello"); } public static void main(String... s) { System.out.println("main from Hello");
Got a problem with generics, which I'm still pretty new at. Here's a program that compiles fine:
import java.util.ArrayList; import javax.swing.JComponent; public class Experiments { public static void main(String[] args) { ListHolder holder = new ListHolder();
[Code] ....
It's useless, but it compiles. If I change Line 14, however, to add a generic type parameter to the ListHolder class, Line 10 no longer compiles:
import java.util.ArrayList; import javax.swing.JComponent; public class Experiments { public static void main(String[] args) { ListHolder holder = new ListHolder();
[Code] ....
I get this error:
Uncompilable source code - incompatible types: java.lang.Object cannot be converted to javax.swing.JComponent at experiments.Experiments.main(Experiments.java:10)
Apparently, the introduction of the type parameter leaves the compiler thinking that aList is of type Object. I can cast it, like this:
JComponent c = ((ArrayList<JComponent>)holder.aList).iterator().next();
That makes the compiler happy, but why is it necessary? How does adding the (unused) type parameter to the ListHolder class end up making the compiler think the aList member of an instance of ListHolder is of type Object?
Trying to make a universal tool for increment an array by one while keeping all the previous values in place.
public K[] increment(K[] k){ int i = 0; K[] tmp = (K[])new Object[Array.getLength(k)+1]; /* * Parses through the passed k and fills tmp with all of ks values
I am trying to create an empty array that has no assigned length as the amount of elements it needs to hold will be dependent on another value. I then want to use a while loop to assign values to it. Here is an example of what im looking for it doesnt work. Iam trying to do:
int x = 12; int i = 1; int k = 0; int[] factors = {} while (i<x) { if (x%i==0) { factors[k] = i; k++; i++;
I'm trying to build a monopoly like game, and atm I'm trying to find way how to build the Community and Chance chest cards. so far, my logic is
1-create an ArrayList of cards with a given order
2-for a given number of times(for loop) generate 2 random numbers ,which will be the parameters for Collection.swap().
3-swap.
here's the code for the shuffler Button
shuffler.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { for(int i=0;i<shuffeledMessages.length;i++){ int randoma=(int)(Math.random()*4); int randomb=(int)(Math.random()*4); Collections.swap(myMessages,randoma,randomb); } } });
For now things seem to work pretty ok, but I'm wondering if this is a good and efficient way to shuffle a card chest especially in case of large number of cards. plus, I'm not sure what would be a good loop count for effective shuffling, in my case I used i<arraylist.size
1) I'm trying to use a logarithm to determine the length of a user input number. I keep getting an error stating <> indetifier expected. I'm assuming this means that the program is not recognizing the function of a logarithm. I know that normally you can include that information in the method, but my teacher has stated specifically that each of these methods be called something else, as shown in the code.
2) I'm not quite sure I understand how to assign the numbers I obtain from the modular equation to a certain position in the array. As I'm asking the user to input any number these values can change so therefore I can't simply state that first number = this place.Here is my code:
import javax.swing.*; import javax.*; public class getSize { public static void main( String[] args )
Started learning about Array's I'm doing an exercise where you create a for loop that randomly assigns values to each element within the array, but where is my code going wrong?
import java.util.Scanner; public class ArrayExamples{ public static void main(String[] args) { Scanner input = new Scanner(System.in); double exampleArray[] = new double[5]; System.out.print("Enter a Number: "); int num1 = input.nextInt();
I am writing a program for a game. It is between the user and a virtual player. The game starts with a pool of consecutive integers 1-100. The size of the pool is based on a random generated number at the beginning of the game. At the start, both players' scores are 0. For each turn, the player picks one number from the pool. That value is added to the player's score, the computer gets the sum of all the remaining numbers in the pool that divide evenly into the player's pick. The player's pick and its divisors are then removed from the pool.
The player should be able to play the game as many times as she wants without ending the program. Instructions should appear on the screen only once at the start of the program.
For each turn, both players' current score, the current pool of numbers, and a prompt for a number to be entered should show onscreen. I have written the code until I get to the function that updates the pool of numbers after a turn.
import java.util.Scanner; import java.util.Random; public class SlickPick { public static void main (String[] args){ Scanner read = new Scanner(System.in); int []pool = new int[100];
[Code] ....
My thinking is that I need to use the binary search to find the indexes of the divisors array and then use those indexes as the start values. I'm not sure how to assign the divisors indexes to start. Do I need an array for start? Whenever I run the program, the only value missing is 3.
//Name : poolUpdate //Description : This function modifies the contents of the pool as a result of a turn of play. //Parameters : The pool array, the divisors array, the size, and the user's pick. // : //Return : public static void poolUpdate(int[] pool, int[] divisors, int size, int pick){ int low=0; int high=size-1;
It is important to note that the inference algorithm uses only invocation arguments, target types, and possibly an obvious expected return type to infer types. The inference algorithm does not use results from later in the program.
Generic methods are methods that introduce their own type parameters. This is similar to declaring a generic type, but the type parameter's scope is limited to the method where it is declared. Static and non-static generic methods are allowed, as well as generic class constructors.
1. The method is only exclusively to be used for the declared argument parameter? For example given a generic method:public static <String, Integer> boolean method(Pair<K, V> p1) {}I could only invoke the method if Pair argument parameter is <String, Integer>?
I have set up a project in Eclipse 3.1 and am using java 5.0 compiler.
Here's my folder structure in Eclipse
Java Code:
DFSRemoteClientTestClient.java mh_sh_highlight_all('java'); DFS is the project in Eclipse
And this is how it looks my java class
Java Code:
package RemoteClient; import java.util.*; // other imports public class TestClient { public static void main(String [] args) throws ServiceInvocationException { // business logic here .... } } mh_sh_highlight_all('java');
So, basically, my java class is just a simple class with a main function.
Now when I build my project, using Project->Clean...
Then I get this as an error at the very first line where i specify the package
This is the error:
Java Code: The type Class is not generic; it cannot be parameterized with arguments <T> mh_sh_highlight_all('java');
Is this the proper way to add to a generic list? My code works just fine, but I got this feeling that there might be some kind of flaw in it or something. Is this pretty much the basic way to add any type of data to a generic list?
import java.util.LinkedList; public class ListOfGeneric<E> { private LinkedList<E> myList;
The objective of the code is to add new records based on existing records with a partial change to the key. I'm getting "type of the expression must be an array type but it resolved to DstidArray" on dsTidRecTbl[i]
String stMajor = request.getParameter("stMajorVersion"); String stMinor = request.getParameter("stMinorVersion"); String stPatch = request.getParameter("stPatchVersion"); StringBuffer stKeySB = new StringBuffer(stMajor+stMinor+stPatch); String stKey = new String(stKeySB.toString()); DstidArray dsTidRecTbl = new DstidArray(stKey); request.setAttribute("dsTidRecTbl", dsTidRecTbl);
I just tried to fill an array with some numbers, calculated by a other function.I just tried to print this array as array, but it doesnt work. Maybe its just about the main method.
public static void main(String[] args) { ggT(5); }
I am following this article [URL] .... till now I have made some code
This is my Interface
public interface Comparable<T> { public int compareTo(T o); }
And this is my class where I am using Bound Type Parameter on Generic Methods
public class GenericMethodBoundType { public static <T extends Comparable<T>> int countGreaterThan(T[] anArray, T elem) { int count = 0; for (T e : anArray)
[Code] .....
What else I need to do both in main method and at what parameterized types I need to pass at the class?
I have a string array but each cell in the 1d string array stores each character the text file is :
"START START START The quick brown fox jumps over the lazy dog 1234567890-= !"$%^&*()_+ QWERTYUIOP{}ASDFGHJKL:@~|ZXCVBNM<><? /.,mnbvcxzasdfghjkkl;'#][poiuytrewq789654123.0 +-*/``""$% hello this is a test file using all the characters availible on the keyboard for input END END END END"
so in the string it is:[0] = S, [1]=A, [2]=R ...ect along the text basically i need to convert each character in each cell of the 1d string array to its hesidecimal value..i have created my own method which will take in a char and return a string containing the charcters hex value.
public static String toHex(char c) { char char2ascii = c; int i = 0; int num = (int) char2ascii; String hex ="";
[code]...
what i want to do is run each cell through the toHex method so i eventually have a string array containing the hex value of each character in my text.
example..i want:
String[] hexarray = S, T, A, R, T
a run it through my method to convert to hex then it will become
String[] hexarray = 53, 54, 41, 52, 54
Im not allowed to use inbuilt libarys and classes to do the hex conversion thats why i have my own method for it .
I have to create an inventory program that displays a product number, name of product, number of units in stock, price of each unit, and then at the end total up the entire value of the inventory. I am a beginner as I am 5 weeks into my first programmer class and I do want to learn how to program. I am able to get the inventory array with the (int) to display in the columns but I do not know how to get the String array with the DVD's to display where they are suppose to. I also cannot figure out how to calculate the quantity with the price to give me an overall total.
This is my code so far:
public class Product // begin Product class { int Stock[] = { 101, 102, 103, 104, 105 }; String[] DVD = new String[5]; double Price[] = { 10.00, 10.00, 12.50, 18.50, 11.50 }; int Quantity[] = { 1, 5, 4, 3, 4 };
private int coin; Money(int c) { coin = c; } int showCoin() { return coin; }
and for a test class, I need an array list with a couple of coins in it (i.e. ONE_POUND, TWO_POUNDS) and a loop that adds together the values of the coins in the list and prints the result. How can I do this?
