I faced some problem in topic inheritence in this i make a Baseclass a "Animal" and its subClass
"Dog" but after makin object of Dog i print no of legs ,eyes ,sound but after the code run there is written eyes=0;legs=0;& sound=null.
Below is my code..
class Animal{
int legs;
int eyes;
public void setEyes(int i){
i=eyes;
return;
}
public int getEyes(){
return eyes;
}
public void setLegs(int i){
i=legs;
return;
}
public int getLegs(){
return legs;
}
}
class Dog extends Animal{
String sound;
public void setSound(String i){
i=sound;
return;
}
public String getSound(){
return sound;
}
}
public class practice_oops{
public static void main(String[] args) {
Dog D=new Dog();
D.setEyes(2);
D.setLegs(4);
D.setSound("bark");
System.out.println(D.getEyes());
System.out.println(D.getLegs());
System.out.println(D.getSound());
}
}
You should set
eyes=i,
legs=i,
sound=i
in the
setEyes(),
setLegs(),
setSound()
functions respectively.
Related
interface A {
public void eg1();
}
interface B {
public void eg1();
}
public class SomeOtherClassName implements A, B {
#Override
public void eg1() {
System.out.println("test.eg1()");
}
}
What is the output and what occurs if method is overriden in interface?
First of all it's of no use to implement both class A and B as both
of them has same method signature i.e both has same method name and
return type.
Secondly you'll need a main method to run the program.
Also in interface you can only declare the methods, the implementation
has to be done in the class which implements it.
interface A {
public void eg1();
}
interface B {
public void eg1();
}
public class Test implements A{
#Override
public void eg1() {
System.out.println("test.eg1()");
}
public static void main (String args[]) {
A a = new test();
a.eg1();
}
}
Output : test.eg1()
So I have a method like so (Method1):
public class Levels extends JFrame{
public void levelClass() {
if(menu.playerClass.equals("Warrior")) {
// I NEED COMMAND HERE
}
}
}
and I want to know how to run this class method (that is in a different class):
public class Classes {
public void listClasses() {
class Warrior { // THIS ONE
int health=100;
int evasionChance=20; // Percentage
int maxAttackDamage=30;
int minAttackDamage=25;
int numHealthPotions=2;
}
}
}
from the first code aka Method1.
Edit
DON'T
Change all:
public class Classes {
public void listClasses() {
class Warrior {
int health=100;
int evasionChance=20; // Percentage
int maxAttackDamage=30;
int minAttackDamage=25;
int numHealthPotions=2;
}
}
}
To:
public class Classes {
public void Warrior {
int health=100;
int evasionChance=20; // Percentage
int maxAttackDamage=30;
int minAttackDamage=25;
int numHealthPotions=2;
}
}
To call a method on a class, you need to instantiate the class.
public class Levels extends JFrame{
public void levelClass() {
if(menu.playerClass.equals("Warrior")) {
// instantiate the Classes class
Classes classes = new Classes();
// call the warrior method
classes.warrior();
}
}
}
IPlugin Calss Library
namespace IPlugin
{
public interface IPlugin
{
string Name { get; set; }
void Start();
void Stop();
}
[Export(typeof(IPlugin))]
public abstract class BasePlugin:IPlugin
{
private string _name;
public BasePlugin()
{
Name = "Base Plugin";
}
public string Name
{
get { return _name; }
set { _name = value; }
}
public virtual void Start()
{
fnDowWork();
}
protected abstract void fnDowWork();
public virtual void Stop()
{
}
}
}
Test Plugin Class Library
namespace TestPlugin
{
public class TestPlugin:IPlugin.BasePlugin
{
public TestPlugin()
{
Name = "Test Plugin";
}
protected override void fnDowWork()
{
Console.WriteLine("Do Work !");
}
}
}
Console Application
class Program
{
static void Main(string[] args)
{
var app = new MyApp();
foreach (var p in app._Plugins)
{
p.Start();
}
}
}
public class MyApp
{
[ImportMany(typeof(IPlugin.IPlugin))]
public IEnumerable<IPlugin.IPlugin> _Plugins;
public string _PluginFolder { get; set; }
public string _StartupPath { get; set; }
public MyApp()
{
_StartupPath = Environment.CurrentDirectory;
var pluginFolderName = System.Configuration.ConfigurationManager.AppSettings["PluginFolder"];
_PluginFolder = System.IO.Path.Combine(_StartupPath, pluginFolderName);
InitializeMEF();
}
private void InitializeMEF()
{
var dirCatalog = new DirectoryCatalog(_PluginFolder, "*.dll");
CompositionContainer container = new CompositionContainer(dirCatalog);
container.ComposeParts(this);
}
}
the DirectoryCatalog find tow Assembly IPlugin.dll and TestPlugin.dll and after Compose parts
the myApp._Plugins is not null but its empty , i don't know where i am doing wrong!
You will need to use the InheritedExportAttribute instead of the ExportAttribute:
[InheritedExport(typeof(IPlugin))]
public abstract class BasePlugin:IPlugin
Note that this will only work for plugins that derive from BasePlugin. Other implementations of IPlugin will not be marked for export. To do this you will have to decorate the interface instead.
I've been studying this accepted answer to a similar question in which what I believe is a concrete factory returns an implementation based on a string argument on the factory method matching a named binding on the concrete implementation.
I'm struggling to get a slightly more complex example to work properly when the factory is an abstract factory, and I wish to use Ninject convention-based binding. Consider the following test:
[Fact]
public void VehicleBuilderFactory_Creates_Correct_Builder_For_Specified_Client()
{
// arrange
StandardKernel kernel = new StandardKernel();
kernel.Bind(typeof (IVehicleBuilderFactory<,>))
.ToFactory(() => new UseFirstArgumentAsNameInstanceProvider())
.InSingletonScope();
kernel.Bind(scanner => scanner
.FromThisAssembly()
.SelectAllClasses()
.WhichAreNotGeneric()
.InheritedFrom(typeof(IVehicleBuilder<>))
.BindAllInterfaces());
var bicycleBuilderFactory =
kernel.Get<IVehicleBuilderFactory<IVehicleBuilder<BlueBicycle>, BlueBicycle>>();
string country = "Germany";
string localizedColor = "blau";
// act
var builder = bicycleBuilderFactory.Create<IVehicleBuilder<BlueBicycle>>(country);
Bicycle Bicycle = builder.Build(localizedColor);
// assert
Assert.IsType<BlueBicycleBuilder_Germany>(builder);
Assert.IsType<BlueBicycle>(Bicycle);
Assert.Equal(localizedColor, Bicycle.Color);
}
Here's where I try juggling with torches & knives 'cause I saw it on the internet once:
public class UseFirstArgumentAsNameInstanceProvider : StandardInstanceProvider
{
protected override string GetName(MethodInfo methodInfo, object[] arguments) {
return methodInfo.GetGenericArguments()[0].Name + "Builder_" + (string)arguments[0];
// ex: Germany -> 'BlueBicycle' + 'Builder_' + 'Germany' = 'BlueBicyleBuilder_Germany'
}
protected override ConstructorArgument[] GetConstructorArguments(MethodInfo methodInfo, object[] arguments) {
return base.GetConstructorArguments(methodInfo, arguments).Skip(1).ToArray();
}
}
I get stabbed and set ablaze when I try to assign bicycleBuilderFactory with this error:
System.InvalidCastException was unhandled by user code
Message=Unable to cast object of type 'Castle.Proxies.ObjectProxy' to type 'Ninject.Extensions.Conventions.Tests.IVehicleBuilderFactory`2[Ninject.Extensions.Conventions.Tests.IVehicleBuilder`1[Ninject.Extensions.Conventions.Tests.BlueBicycle],Ninject.Extensions.Conventions.Tests.BlueBicycle]'.
Source=System.Core
StackTrace:
at System.Linq.Enumerable.<CastIterator>d__b1`1.MoveNext()
at System.Linq.Enumerable.Single[TSource](IEnumerable`1 source)
at Ninject.ResolutionExtensions.Get[T](IResolutionRoot root, IParameter[] parameters) in c:\Projects\Ninject\ninject\src\Ninject\Syntax\ResolutionExtensions.cs:line 37
at Ninject.Extensions.Conventions.Tests.NinjectFactoryConventionsTests.VehicleBuilderFactory_Creates_Correct_Builder_For_Specified_Client() in C:\Programming\Ninject.Extensions.Conventions.Tests\NinjectFactoryConventionsTests.cs:line 40
InnerException:
Is it possible to bind using the ToFactory() method and custom provider, using the factory method argument ("Germany") along with the generic type argument (IVehicleBiulder<BlueBicycle>, BlueBicycle) to resolve the type?
Here's the rest of the code for the test, as compact and readable as I could make it.
public interface IVehicleBuilderFactory<T, TVehicle>
where T : IVehicleBuilder<TVehicle> where TVehicle : IVehicle
{
T Create<T>(string country);
}
VehicleBuilder implementations
public interface IVehicleBuilder<T> where T : IVehicle { T Build(string localizedColor); }
abstract class BicycleBuilder<T> : IVehicleBuilder<T> where T : Bicycle
{
public abstract T Build(string localizedColor);
}
public abstract class RedBicycleBuilder : IVehicleBuilder<RedBicycle>
{
private readonly RedBicycle _Bicycle;
public RedBicycleBuilder(RedBicycle Bicycle) { _Bicycle = Bicycle; }
public RedBicycle Build(string localizedColor)
{
_Bicycle.Color = localizedColor;
return _Bicycle;
}
}
public abstract class GreenBicycleBuilder : IVehicleBuilder<GreenBicycle>
{
private readonly GreenBicycle _Bicycle;
public GreenBicycleBuilder(GreenBicycle Bicycle) { _Bicycle = Bicycle; }
public GreenBicycle Build(string localizedColor)
{
_Bicycle.Color = localizedColor;
return _Bicycle;
}
}
public abstract class BlueBicycleBuilder : IVehicleBuilder<BlueBicycle>
{
private readonly BlueBicycle _Bicycle;
public BlueBicycleBuilder(BlueBicycle Bicycle) { _Bicycle = Bicycle; }
public BlueBicycle Build(string localizedColor)
{
_Bicycle.Color = localizedColor;
return _Bicycle;
}
}
public class RedBicycleBuilder_USA : RedBicycleBuilder {
public RedBicycleBuilder_USA(RedBicycle Bicycle) : base(Bicycle) { }
}
public class RedBicycleBuilder_Germany : RedBicycleBuilder {
public RedBicycleBuilder_Germany(RedBicycle Bicycle) : base(Bicycle) { }
}
public class RedBicycleBuilder_France : RedBicycleBuilder {
public RedBicycleBuilder_France(RedBicycle Bicycle) : base(Bicycle) { }
}
public class RedBicycleBuilder_Default : RedBicycleBuilder {
public RedBicycleBuilder_Default(RedBicycle Bicycle) : base(Bicycle) { }
}
public class GreenBicycleBuilder_USA : GreenBicycleBuilder {
public GreenBicycleBuilder_USA(GreenBicycle Bicycle) : base(Bicycle) { }
}
public class GreenBicycleBuilder_Germany : GreenBicycleBuilder {
public GreenBicycleBuilder_Germany(GreenBicycle Bicycle) : base(Bicycle) { }
}
public class GreenBicycleBuilder_France : GreenBicycleBuilder {
public GreenBicycleBuilder_France(GreenBicycle Bicycle) : base(Bicycle) { }
}
public class GreenBicycleBuilder_Default : GreenBicycleBuilder {
public GreenBicycleBuilder_Default(GreenBicycle Bicycle) : base(Bicycle) { }
}
public class BlueBicycleBuilder_USA : BlueBicycleBuilder
{
public BlueBicycleBuilder_USA(BlueBicycle Bicycle) : base(Bicycle) { }
}
public class BlueBicycleBuilder_Germany : BlueBicycleBuilder {
public BlueBicycleBuilder_Germany(BlueBicycle Bicycle) : base(Bicycle) { }
}
public class BlueBicycleBuilder_France : BlueBicycleBuilder
{
public BlueBicycleBuilder_France(BlueBicycle Bicycle) : base(Bicycle) { }
}
public class BlueBicycleBuilder_Default : BlueBicycleBuilder
{
public BlueBicycleBuilder_Default(BlueBicycle Bicycle) : base(Bicycle) { }
}
Vehicle implementations:
public interface IVehicle { string Color { get; set; } }
public abstract class Vehicle : IVehicle { public string Color { get; set; } }
public abstract class Bicycle : Vehicle { }
public class RedBicycle : Bicycle { }
public class GreenBicycle : Bicycle { }
public class BlueBicycle : Bicycle { }
Based on comments from #LukeN, I've refactored the Bicycle class, so that its color is set through constructor injection with an IColorSetter. The IColorSetter implementation has a generic Color type, and each of the Color implementations are 'localized' by way of constructor injection with an IColorLocalizer<T>.
This way, no class seems to have knowledge of anything beyond what is logically its responsibility (I think).
However, I'll need to think about this more to see how the refactored classes shown below can be used to show how to use a Ninject custom instance provider could be used to pick the property IColorLocalizer<T> now, since it's the only class that will know about colors and languages; the color coming from its generic type, and the language coming from the name of the implementation itself.
Since asking the original post, I've moved away from using an IoC container to make choices like this, choosing instead to programmatically put in code a switch for picking an implementation, with a default implementation selected for any unhandled outlier cases. But I'm not sure if it's mainly to get beyond something that's stumped me, or because it's a poor choice to lean on an IoC container in this way.
I'll need to update this answer more as I think about it.
Vehicles
public abstract class Vehicle {
public abstract string Color { get; internal set; }
public abstract string Move();
}
public class Bicycle : Vehicle {
public Bicycle(IColorSetter colorSetter) { colorSetter.SetColor(this); }
public override string Color { get; internal set; }
public override string Move() { return "Pedaling!"; }
}
Color setters
public interface IColorSetter { void SetColor(Vehicle vehicle); }
public class ColorSetter<T> : IColorSetter where T : Color
{
private readonly T _color;
public ColorSetter(T color) { _color = color; }
public void SetColor(Vehicle vehicle) { vehicle.Color = _color.Name; }
}
Color localizers
public interface IColorLocalizer<in T> where T : Color {
void LocalizeColor(T color);
}
public class GermanBlueLocalizer : IColorLocalizer<Blue> {
public void LocalizeColor(Blue color) { color.Name = "blau"; }
}
public class EnglishBlueLocalizer : IColorLocalizer<Blue> {
public void LocalizeColor(Blue color) { color.Name = "blue"; }
}
Colors
public abstract class Color { public string Name { get; internal set; } }
public class Red : Color {
public Red(IColorLocalizer<Red> colorLocalizer) {
colorLocalizer.LocalizeColor(this); }
}
public class Green : Color {
public Green(IColorLocalizer<Green> colorLocalizer) {
colorLocalizer.LocalizeColor(this); }
}
public class Blue : Color {
public Blue(IColorLocalizer<Blue> colorLocalizer) {
colorLocalizer.LocalizeColor(this); }
}
I know there is a Comparable interface, trying to figure out how to write my own.
Here's the interface
public interface MyComparable {
public boolean lt(Object other);
}
and a class that implements it and packages an int (yes, I know there is an Integer class)
public class MyInteger implements MyComparable {
private int value;
public MyInteger(int v)
{ value = v; }
public void set(int v)
{ value = v; }
public int get()
{ return value; }
public boolean lt(MyInteger other)
{ return get() < other.get(); }
}
I get " MyInteger is not abstract and does not override abstract method eq(Object) in MyInteger error". MyComparable doesn't declare an eq method. So it's comping from the superclass but I don't understand.