How to get an instance of my object's parent
Is there a way in Java to get an instance of my object's parent class from that object?
ex.
public class Foo extends Bar {
public Bar g开发者_StackOverflow中文版etBar(){
// code to return an instance of Bar whose members have the same state as Foo's
}
}
There's no built-in way to do this. You can certainly write a method that will take a Foo and create a Bar that's been initialized with the relevant properties.
public Bar getBar() {
Bar bar = new Bar();
bar.setPropOne(this.getPropOne());
bar.setPropTwo(this.getPropTwo());
return bar;
}
On the other hand, what inheritance means is that a Foo is a Bar, so you could just do
public Bar getBar() {
return this;
}
Long story short:
return this;
If you want to return a copy, then create a copy constructor on Bar that receives another Bar.
public Bar(Bar that) {
this.a = that.a;
this.b = that.b;
...
}
this this is an instance of bar, the simple thing is just "return this;" but if you need a distinct object, perhaps you could implement java.lang.Clonable and "return this.clone();"
If your class extends Bar, it is an instance of Bar itself. So
public Bar getBar() {
return (Bar) this;
}
should do it. If you want a "different instance", you can try:
public Bar getBar() {
return (Bar) this.clone();
}
Since Foo is-a Bar, you can do this:
return this;
This will only return the parent instance of current object.
You can use reflection
package com;
class Bar {
public void whoAreYou(){
System.out.println("I'm Bar");
}
}
public class Foo extends Bar{
public void whoAreYou() {
System.out.println("I'm Foo");
}
public Bar getBar() {
try {
return (Bar)this.getClass().getSuperclass().newInstance();
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
}
throw new RuntimeException();
}
public static void main() {
Foo foo = new Foo();
foo.whoAreYou();
foo.getBar().whoAreYou();
}
}
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