Class Student {
public void setName(String name){
//Some implementation
}
public void setName(Object name){
// some implementation
}
}
I have a class Student with overload methods, i just want to know, which method will be called and why?
Student s = new Student()
s.setName("abc");
EDIT
Language: JAVA
It will call setName(String name)function as you are passing the String and not object of String.
Related
Say i have a code as follows
interface Interface1
{
void method1();
}
interface Interface2
{
void method2();
}
class ClassWithInterfaces : Interface1,Interface2
{
void method1(){}
void method2(){}
}
Now in my "manager" class i implement this as follows :
public OtherClass
{
Interface1 interface1;
Interface2 interface2;
public void someMethod()
{
ClassWithInterfaces classWithInterfaces = new ClassWithInterfaces();
interface1 = classWithInterfaces;
interface2 = classWithInterfaces
}
}
I don't feel that this is the right way to do it hovewer i can't come up with other solutions i can't use Dependency Injection Frameworks in my project if you ask about that. Can you tell me wheter apart from DI there is a better way of doing that?
Hello and welcome to Stack Overflow :-)
You don't have to use a framework in order to do DI. In fact, there are some languages that make it impossible to use a framework for DI - e.g., C++.
Any way, in your case, the proper way to do DI is like this:
interface Interface1
{
void method1();
}
interface Interface2
{
void method2();
}
interface Interface3 : Interface1, Interface2
{
void method1();
void method2();
}
class ClassWithInterfaces : Interface3
{
void method1(){}
void method2(){}
}
public OtherClass
{
Interface3 m_interface3;
OtherClass(Interface3 interface3)
{
m_interface3 = interface3;
}
public void someMethod()
{
m_interface3.method1();
m_interface3.method2();
}
}
// And now the usage:
public main()
{
ClassWithInterfaces classWithInterfaces = new ClassWithInterfaces();
OtherClass otherClass = new OtherClass(classWithInterfaces);
}
I upgraded my spring stream from 1.3.0 to 2.1.2 and the default serializer was changed from Kyro (deprecated) into Jackson.
I have a kafka topic that more than one type of messages can be sent to. With Kyro I used to deserialize it into Object.class and then cast it to the relevant type of class.
With jackson I can't achieve this functionality, because I have to specify the type of class I want to deserialize to in advance, otherwise, it's been deserialized into a string.
I tried to find an example but couldn't find anything. Any ideas how can I achieve the same functionality? I want to make it as efficient as possible.
You can add hints to the Jackson encoding so it is decoded to the right concrete type:
#JsonTypeInfo(use=JsonTypeInfo.Id.CLASS, include=JsonTypeInfo.As.PROPERTY, property="#class")
#SpringBootApplication
#EnableBinding(Processor.class)
public class So56753956Application {
public static void main(String[] args) {
SpringApplication.run(So56753956Application.class, args);
}
#StreamListener(Processor.INPUT)
public void listen(Foo foo) {
System.out.println(foo);
}
#Bean
public ApplicationRunner runner(MessageChannel output) {
return args -> {
output.send(new GenericMessage<>(new Bar("fiz")));
output.send(new GenericMessage<>(new Baz("buz")));
};
}
#JsonTypeInfo(use=JsonTypeInfo.Id.CLASS, include=JsonTypeInfo.As.PROPERTY, property="#class")
public static abstract class Foo {
private String bar;
public Foo() {
super();
}
public Foo(String bar) {
this.bar = bar;
}
public String getBar() {
return this.bar;
}
public void setBar(String bar) {
this.bar = bar;
}
#Override
public String toString() {
return getClass().getName() + " [bar=" + this.bar + "]";
}
}
public static class Bar extends Foo {
public Bar() {
super();
}
public Bar(String bar) {
super(bar);
}
}
public static class Baz extends Foo {
public Baz() {
super();
}
public Baz(String bar) {
super(bar);
}
}
}
and
com.example.So56753956Application$Bar [bar=fiz]
com.example.So56753956Application$Baz [bar=buz]
See here.
You can still use Kryo if you want. You can just add it manually using #StreamMessageConverter- https://cloud.spring.io/spring-cloud-stream/spring-cloud-stream.html#spring-cloud-stream-overview-user-defined-message-converters.
With regard to "With jackson I can't achieve this functionality, because I have to specify the type of class. . ." - that is not accurate since the type of the class gets picked up from the signature of the handler method and it is transparent to you as a user.
This is a question about abstraction.
I want to be able to use two completely different GUIs for my application. They are completely different but implements the same interface.
My question is, what will the constructor look like? What type of object goes in the signature?
They do not extend a common parent, so I can't use polymorphism.
controller object wants to be injected with an object which implements Displayable interface.
interface Displayable {
void display();
}
class Display1 implements Displayable {
public void display() {
//Shows something Fancy on the screen
}
}
class Display2 implements Displayable {
public void display() {
//write something to console
}
}
class Main {
public static void main(String[] args) {
// Controller controller = new Controller(new Display1());
Controller controller = new Controller(new Display2());
controller.display();
}
}
class Controller {
????? display;
public Controller(?????? display) {
this.display = display;
}
public void display() {
display.display();
}
}
Trying to apply a MockUp on a Java 8 default interface method, and JMockit tells me that method cannot be found. This has been tried with JMockit 1.15, 1.19, and 1.25. Here's a very simple use case:
#RunWith(JMockit.class)
public class TestTest {
public interface MyInterface {
default void foo(int f) {
bar(String.valueOf(f));
}
void bar(String s);
}
public class MyClass implements MyInterface {
public void bar(String s) {
System.out.println(s);
}
}
#Test
public void testtest() throws Exception {
new MockUp<MyClass>() {
#Mock
void foo(int i) {
System.out.println("MOCKMOCK " + (i*2));
}
#Mock
void bar(String s) {
System.out.println("MOCK " + s);
}
};
MyClass baz = new MyClass();
baz.foo(5);
baz.bar("Hello world");
}
}
This gets me the error
java.lang.IllegalArgumentException: Matching real methods not found for the following mocks:
com.example.dcsohl.TestTest$1#foo(int)
at com.example.dcsohl.TestTest$1.<init>(TestTest.java:29)
at com.example.dcsohl.TestTest.testtest(TestTest.java:29)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
...
How can we #Mock this method?
Slightly modifying your use case to return strings instead of printing to standard out the following solution will work.
import static org.junit.Assert.assertEquals;
import org.junit.Test;
import mockit.Expectations;
public class TestTest {
public interface MyInterface {
default String foo(int f) {
return bar(String.valueOf(f));
}
String bar(String s);
}
public class MyClass implements MyInterface {
public String bar(String s) {
return s;
}
}
#Test
public void testtest() throws Exception {
MyClass baz = new MyClass();
new Expectations(MyClass.class) {{
baz.foo(anyInt); result = "FOOMOCK";
baz.bar(anyString); result = "BARMOCK";
}};
assertEquals(baz.foo(5), "FOOMOCK");
assertEquals(baz.bar("Hello world"), "BARMOCK");
}
}
There are many useful examples of how to mock out interfaces with method bodies (ie default or static methods) outlined in the examples section on the jmockit github repository.
Use #Mocked instead of a MockUp, it supports default methods.
I have this class:
public class MyClass {
public void updatePeople(List<Person> people) { //DO STUFF }
}
I want to log the size of people when updatePeople is called by AOP.
This is my aspect:
#Aspect
public class MyAspect {
#Pointcut("execution(void com.bla.bla.MyClass.updatePeople(List<Person>)) && args(people)")
public void updatePeople(List<Person> people) {}
#Before("updatePeople(people)")
public void log(List<Person> people) {
log(people.size());
}
}
But log is never called. I guess List<Person> syntax is is not correct in the pointcut. How can I do that?
Thanks.
Solved! I changed the pointcut into this:
#Pointcut("execution(void com.bla.bla.MyClass.updatePeople(..)) && args(people)")
public void updatePeople(List<Person> people) {}