generics error

[karthik swamy]

class Equal<T>{
	private T str1;
	private T str2;
	public void setData(T str1,T str2){
		this.str1 = str1;
		this.str2 = str2;	
	}	
	public T getData(){
	             String s=null;
		if(str1.equals(str2)){
			s="matched";
		}else{
			s="not matched";
		}
		return s;	
	}

}

public class strMatching{
	public static void main(String ...args){
		Equal<String> e = new Equal<String>();
		e.setData("hello","hello1");
		System.out.println("The value is ::::::::::::::"+e.getData());

	}
}

i am getting this error after compiling :

E:\Program Files\Java\jdk1.6.0\bin>javac strMatching.java
strMatching.java:12: incompatible types
found   : java.lang.String
required: T
                        s="matched";
                          ^
strMatching.java:14: incompatible types
found   : java.lang.String
required: T
                        s="not matched";

so please suggest me where i am wrong.


Thanks,
karthik swamy.

[Seetharaman Venkatasamy]

your *public T getData() * expect the generic return type T . but you have returned a string!

so change the method return type as String[preferable approach] else cast the string to T and return as in *return (T)s*;

<edit>added clarity</edit>

[Seetharaman Venkatasamy]

and please use code tag when you post code!

[karthik swamy]

Seetharaman Venkatasamy wrote:your *public T getData() * expect the generic return type T . but you have returned a string!

so change the method return type as String[preferable approach] else cast the string to T and return as in *return (T)s*;

<edit>added clarity</edit>

thanks its working,but can it wil work for integer type

[Seetharaman Venkatasamy]

karthik swamy wrote:but can it wil work for integer type

actually *return (T)s* this lead you in confusion. that is why I said first approach is preferable. Yes , it will work for an Integer type also

[karthik swamy]

Seetharaman Venkatasamy wrote:

karthik swamy wrote:but can it wil work for integer type

actually *return (T)s* this lead you in confusion. that is why I said first approach is preferable. Yes , it will work for an Integer type also

but generics is used for auto typecast then why we are typecasting like return (t)s

[Seetharaman Venkatasamy]

karthik swamy wrote:but generics is used for auto typecast then why we are typecasting like return (t)s

your T getData implementation force us to do that! you should reimplement[even signature of method] the method!