24 Topics
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## Introduction ## In Java, a common way to express a type that is a combination of two or more types is to just create an interface that extends the other types. The problem with this approach is that your code might be littered with interface declarations, polluting your code … |
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Hello all I am using Generics in Java to perform some arithmetic operations, but I am getting some error **The operator + is undefined for the argument type(s) T, T** here is my code package com.genericsexample; public class GenericsArithmetic<T> { private T number1, number2,sum,product,difference; public void AddNumbers(T number1, T number2){ … |
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hi,I have a classB which is in location "test\folder1\generics1" and Class2 which is generic class in another folder for eg test\folder2\ and when i create object for class2 which should be able to acces class1 method which is MethodA() please advise.Thanks in advance namespace generics1 { public class B { … |
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public class SongIterator<T,L> implements Iterator<Song<T, L>> {} |
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Suppose I have the following generic classes; Queue<T> KellysCoffee CheckOut and the following generic interfaces QueueInterface OrderLineInterface Suppose I want `KellysCoffee` to extend Queue class and implement `OrderLineInterface` This is how I've done it private class KellyCoffee<Order extends Queue<Order>> implements OrderLineInterface{} Now when I try to implement `CheckOut` public class … |
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would you just do @Override public boolean contains(T param){ return hashTable[function(param)]!=null; } |
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I'm having trouble pinpointing the exact definition of a generic linkedstack class Suppose I have public class LinkedStack<T> { //some variables //would this be right LinkedStack(){ } //for a generic constructor of type T for the LinkedStack class of type T? } |
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Hi everyone, we were taught about Generics and Interfaces at uni and I wasn't sure what the perfect situations are to use interfaces because they don't have implementation in them so they work as a contract to other classes where everyone can implement their methods as long as they extend … |
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public class GenericDemo<E extends GenericDemo> { E innerE; public E doStuff(E e, GenericDemo<E> e2) { //insert code here } public E getE() { return innerE; } } The options are: 1. return e 2. return e2.getE() 3. return e2 4. return e.getE() Option (1) and (2) compile fine. Option (3) … |
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import java.util.*; public class GenericDemo4 { public static void main(String r[]) { Set s1 = new HashSet(); s1.add(0); s1.add("1"); dostuff(s1); } static void dostuff(Set<Number> s) { do2(s); Iterator i = s.iterator(); while(i.hasNext()) System.out.println(i.next() + " "); Object [] oa = s.toArray(); for(int x = 0; x<oa.length; x++) System.out.println(oa[x] + " … |
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import java.util.*; class SampleA { } class SampleB extends SampleA{ } class SampleC extends SampleA{ } class VectorDemo { public static void main(String r[]) { Vector<SampleA> v = new Vector<SampleA>(); v.add(new SampleB()); v.add(new SampleC()); SampleC rect = v.get(2); } } The output says "Incompatible types. Found SampleA, required SampleC. SampleC … |
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Hello all, been a while since I've asked a question. I'm working on a project just to practice and for fun and I've run into a snag. I'm working on a painting type program and I'm trying to get a generic Buffer class for the images so I can use … |
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Related to: C#; Windows form, Storing Multiple Instances of a User Control: Hi: I’ve created an app with a user control that accepts parameters. When a user clicks a button I need to store the current view of the control and bring into focus on demand. Several instances of the … |
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Hellow. I have 3 variables 1. string query; 2. public static OracleCommand oracmd; 3. public static OracleDataReader reader; I have used these variables in a function [CODE=C#] . . . public void PreviousValue() { query = " select * from....... "; oracmd = new OracleCommand(); .... .... reader = oracmd.ExecuteReader(); … |
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The sort methods for collections specifies that the parameter must be a collection of objects that implement Comparable for their own class or superclass, eg [CODE]public static <T extends Comparable<? super T>> void sort(List<T> list)[/CODE] Can anyone tell me how to define an ArrayList that will only accept such objects? … |
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I have a problem with this construction, can not find how to rewrite it properly. [CODE] private SqlParameter op <T> (T? t, string name) { SqlParameter sp = new SqlParameter(); sp.IsNullable = true; sp.ParameterName = name; sp.Value = t.HasValue ? t.Value : Convert.DBNull; return sp; } [/CODE] |
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I'm trying to create a class that reads in a set of numbers from a file, stores them in a generic array, and then sorts them using the generic bubbleSort method. I usually write in C++ and the switch from templates to generics hasn't been easy. I'm fairly certain my … |
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I can understand that the subtype covariance relation should not hold for parameterized types, but why should it hold for arrays ? One of the books (Khalid Moghul) said [QUOTE]This relation holds for arrays because the element type is available at runtime[/QUOTE] How does the element type being available at … |
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Hello. It's been a while since I was on here. I'm writing a Java class with a generic type parameter. Among other things, it maintains an internal ArrayList of the same generic type as itself. In a perfect world, the code would go like this: [CODE=Java]import java.util.ArrayList; public class MyGenericClass<T> … |
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I'm creating a system that has a parameterized class "TypeModule<T>". Now, I have another class that has the following member; [CODE]private LinkedHashMap<Class, ArrayList<TypeModule>> m_modules = ...[/CODE] Here's my dilemma. I need something more like the following; [CODE]private LinkedHashMap<Class<?>, ArrayList<TypeModule<?>>> m_modules = ...[/CODE] The only thing is, I need the '?'s … |
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Hi all, to simplify my problem, I'll use a quick example. Imagine I have a class of 'Cat' which has accessors for things like 'name', 'colour' and 'height'. I then put these cats in a list [CODE]List<Cat^>^ catList;[/CODE] I want to be able to search this list based on the … |
Hi, I am working on assignments that deal with Generics in java. I have a class Movie that have a String name variable. However I have to add a few more properties to Movie objects like Release year and Director name. So I created an Inventory class that uses the … |
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I am getting the message when i start the computer that Generic Host Process for Win32 Services Error. I have seen the advanced options/details of the message and it is as under: szAppName : svchost.exe szAppVer : 5.1.2600.2055 szModName : wiaservc.dll szModVer : 5.1.2600.2055 offset : 00017f81 Please help me … |
I got yesterday a question how to get average date from list of dates, and here's my answer. |
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