Suppose I have an enum class named Faction and one of the constants is named DAUNT. I created a class of the enum DAUNT but how can I pass in a DAUNT faction type in for Daunt?
Java Code:
public enum Faction { ALMIGHTY, AMBITION, DAUNT, RESTLESS, CAN; }
//new file public class Daunt { public Daunt() { } } mh_sh_highlight_all('java');
public static void doSomething(List<? extends GenericClass> input) { // op }
^
This compiles and works, ensuring I can only pass in a List of a type extending GenericClass.But now I want it to accept an Array instead of List. This is where I'm stuck:
public static void doSomething(<? extends GenericClass>[] input) { // op }
^
A wrong guess at the syntax which does not compile. One solution is to convert Array into ArrayList before calling the 1st method above, but I'd rather bypass this if possible.
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?
Is there anyway to iterate an enum type without an instance. As some context, consider the following code:
Java Code: public interface GenericChecker { public bool isValid(String str); } mh_sh_highlight_all('java'); Java Code: public class EnumChecker<T extends Enum<T> > extends GenericChecker { private Class<T> enumType; //No instance
[code]....
toString method of the enum types has been overridden so that it returns the name assigned to the enum rather than the enum name itself. For example an enum might be SOME_ENUM("Assigned name"), therefore toString returns "Assigned name" rather than "SOME_ENUM". The idea is that a field from a table can be handed to the isValid(String) function on the GenericChecker base, and the derived class will then check to see if the field matches valid data as far as it is concerned.Thus, I can create a whole bunch of checkers easliy:
I have a enum class which contains some string which i am comparing to a string i get from a user
Java Code:
public enum Compare { a, b, c, d, e, f } class SomeClass { String method(String letter){ Compare word= Compare.valueOf(letter); } } mh_sh_highlight_all('java');
Everything works fine but when I added a new word to it like "g" it throws the IllegalArgumentException ?
I am wondering if there is a way in jave to use enums WITHIN a class (without creating a separate enum class) without using private static final. Something like as folows:
class My Class { myEnum {ACTIVE, INACTIVE, PENDING}; }
I am trying to use a custom class in a .jsp page, as part of a course I am taking on Web Technologies.The original version of the jsp page was working fine, until I moved part of the Java code to a separate class.Here is the original .jsp code that is working:
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.
I'm really new to object/class concepts and already having difficulties with applying them. How to create and return an array of Exam objects? I need to get a data from a textfile which is passed to the method.
Java Code:
public Exam(String firstName, String lastName, int ID, String examType, int score) { this.firstName = firstName; this.lastName = lastName; this.ID = ID; this.examType = examType; this.score = score;
I'm really new to object/class concepts and already having difficulties with applying them. how to create and return an array of Exam objects? I need to get a data from a textfile which is passed to the method.
public Exam(String firstName, String lastName, int ID, String examType, int score)
public class Class1 extends AbstractClass { //stuff } public class Class2 extends AbstractClass { //stuff }
within another class I have a private variable with the type of the Abstract class, and within one of the methods I assign an object to the the variable like this:
public class Test { private AbstractClass temp; public testMethod(){ Class1 anObject = new Class1(); temp = anObject; } }
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');
So I'm beginning to learn java with the book HeadFirst Java. The books says that all a tester class does is create objects of a new type and then use the dot operator...
I don't really understand what a tester class is and what it does ? and what is the Dot operator and how does it work ?
I am trying to implement the following example to override the equality and hashCode method if the class has reference type member. I do get the expected result "true" for equal and "false" for non-equal objects. But the print statement in the Circle's equal method is not executed when the objects values are not equal. I don't know what i am missing, though i get the equality result "false" as expected for non equal objects.
class Point{ private int x, y; Point (int x, int y) { this.x =x; this.y = y;
Okay, I am supposed to implement the functionalities of the Set class using a private data member of type ListReferencedBased<E>,how the ListReferenceBased works with what I am trying to accomplish.I am trying to complete Set.java, and I have barely started and much of the code doesn't work. ListReferenceBased was given to me completed.
import java.util.Iterator; pubic class ListReferenceBased<E> implements ListInterface<E>, Iterable<E>{ /** reference to the first element of the list */ private Node<E> head; /** number of items in list */ private int numItems;
I want to have a priceObject which is constructed by a price the enumtype and the name.
public class Testing { public static void main(String[] args) { PreisObject p1 = new PreisObject(1,Price.liquid,"TEST1"); System.out.println(p1); PreisObject p2 = new PreisObject(2,Price('f'),"Test2");
[Code] .....
As you can see with PreisObject2 I want to check the enum by the value and not by the name as in PreisObject1.
Or do I have to use a if-else or switch statement to do something like this?
How would I go about and make an enum, that has Strings and Methods?I want to make a class called GraphicalEffects, this class and be instanstiated and it has a method to apply graphicalEffects AS methods or some type of references to methods in an ArrayList.
So I have an Enum file with 119 constants and each constant of that type has 20 fields that come with it. All the fields are the same type and named the same (e.g. there are 119 of Object obj, one for each constant), and I want to run the same methods over them. Since the Objects of the same type are named the same for each constant, I just have them named explicitly in get-er methods.
This worked fine when I just put all 20 fields through the constructor and set them as fields under all the constants. But I realized that if I wanted to make an instance of this Enum class, I'd have to enter in all 20 fields when they are all a set of Objects with unique values. So I then put them as fields under their own respective constant to make it easier to create instances of this enum. But now my methods don't work.
A) I don't really understand why they don't work anymore? B) Is there a way to fix it without putting all the methods under each constant?
Example:
public enum MyEnum { AAA { private MyObject obj = new MyObject (3.0); }, BBB { private MyObject obj = new MyObject (1.5); }, CCC { private MyObject obj = new MyObject (6.5); }, DDD { private MyObject obj = new MyObject (3.5); };
public double getObjVal() { return obj.value(); // it can't find this obj should I move it up to where the constants are declared? } }
