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 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');
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?
1 import java.util.ArrayList; 2 import java.util.List; 3 4 public class MyList<E> { 5 6 public List<E> list; 7 public int length;
[code]...
I am trying to define a class MyList, which i just a wrapper around an ArrayList, no real purpose, just for the sake of learning Generics. Idea here is that I create a parameterized class, MyList<E>, which holds a parameterized instance var of type List<E>. I have an add method which adds an element of type E to the List<E>. If I create an instance of MyList, call it 'm', for some reason when I try to call a method on that instance the compiler complains that 'm' cannot be found.
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>?
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;
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?
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"
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();
I've implemented Stack on the base of the LinkedList. It works as i expect it to work, but then i tried to made it compatible with foreach loop. I've implemented Iterable and Iterator. Code compiles and works fine, but does not return any output. It looks like while working with foreach, next() is not called at all. If i`m getting iterator from instance and try to do iterator.next(), i get output as expected.
public class genericStack<T> implements Iterator<T>, Iterable<T> { private LinkedList<T> LL ; protected genericStack() { this.LL = new LinkedList<T>(); } public static void main(String[] args) {
package com.Lists; public class EmployeeOffice implements EmpInterface { private double salary; private String name; private String postion; private double hoursWorked;
[Code] .....
So if i wanna sort this Generic class using comaparator what do i do... I cant find an answer to this... I wanna sort them on the basis of salary what to do ...
I've a parent class with a argument constructor like below(a sample code)
public class Parent { Parent(String name) { System.out.println(name); } public static void main(String[] args) { } }
Also I've child.class which extends Parent.class as shown below,
public class child extends Parent { child(String name) { super(name); } }
Now, I want create/modify the constructor which is in child, by taking "int i" as an input instead of "String name". How can I do that? Run time I want to execute child constructor not a parent constructor.
Condition is: Without making any changes to the Parent class
I am writing a program that should take a url and scan the page for any links. It is in the beginning stages, but I ran into an error when I tried to extend a class. There's a lot going on in this code, but the error is caused by the constructor.
Error message at compile time:
"constructor Page in class Page cannot be applied to given types; {//Constructor ^ required: String found: no arguments reason: actual and formal argument lists differ in length".
Here's the code(first my class, then the class I extended)
public class SearchEngine extends Page { public static Color customGreen = new Color(69, 194, 33); public static Color customYellow = new Color(232, 166, 12); public static Color customBlue = new Color(25,97,255); public static Color customYellowComp = new Color(178,125,0);
When creating a class with a constructor, why does one have to create private variables (attributes) to be used as parameters by the object? The object's parameters will be set to be exactly equal to the private variables (attributes), so what is the point of having the private variables (attributes) Why are both private variables (attributes) and parameters needed when they are set to be equal each other anyway?
How do you test a default constructor in one class and then test it in a different class? This is the code for the Person class which has the default constructor. I'm not sure in the PersonTester class how to access this default constructor and how to test it - what I have so far for the second class is also below.
class Person { // Data Members private String name; // The name of this person private int age; // The age of this person private char gender; // The gender of this person
The one problem in my book was to create a constructor for different shirt features, which I did and ran successfully. Out of curiosity, I also added other methods to see if it would run if the parameters were different from the constructor. It keeps giving me a constructor error. So, my question is, am I able to create a class that uses a constructor with parameters and other methods without errors? I'm guessing there's no reason to since it would be wasted space since the constructor could do it but was just curious if it's possible.
Is everything from the constructor down (in the class) and Shirt.oneShirt (in the main) just a waste of time?
Here's my example:
public class Shirt//class name. { int collarSize;//data field. int sleeveLength;//data field. int pocketNumber;//data field public final static String MATERIAL = "cotton";//final data field for material. public Shirt(int collarSize, int sleeveLength, int pocketNumber)//start of constructor. {
I have a class of Date with a constructor with 3 parameters in it. Those 3 parameters are int data type just to enter month, year, day.
I have another class called Author which has a constructor of Date diedDate; as a parameter passing to the Author constructor.
I was asked to call the Date parameter is null, call the default constructor but I thought for the Date parameter I could only enter something like 0,0,0 instead of typing in null, null, null because null is for String data type isn't it?