CODEWITHSUNDEEP
javagenerics
user1089362
user1089362

Reputation: 566

Java generics casting

How please works following generic casting?

private <T, N> N send(final T request) {
    final String serviceUrl = "someUri"

    try {
        return (N) webServiceTemplate.marshalSendAndReceive(serviceUrl, request);
    } catch (final SoapFaultClientException e) {

    }
}

When I call this private method like this:

MyReq request = new  MyReq();
MyResp response = send(req);

How this method casting this object into MyResp object? What mean this in return type:

< T, N>

Upvotes: 2

Views: 403

Answers (4)

locohamster
locohamster

Reputation: 117

< T, N>

Is not a return type. N is.

private <T, N> N send(final T request)
               ↑

You have "choosen" type T by passing MyReq argument. Before returning value of marshalSendAndReceive it is being casted to N type. In your case MyResp.

<T,N>

just declares that this class/method is generic and you may specify generic input type as well ans output.

Upvotes: 1

Deepanshu J bedi
Deepanshu J bedi

Reputation: 1530

Here T and N are Generic parameters.

Here the return type is N not <T,N>.

Read more...

Upvotes: 0

Nabin
Nabin

Reputation: 11776

It's about using templates in java similar to templates in C++;

Example:

void add(T x, T y){
System.out.println(x+y);
}

Above function can be called with either of the following...

add(3.0f, 4.5f);
add(2,3);

Means, the function is for any kind of parameters

Upvotes: 0

merlin2011
merlin2011

Reputation: 75565

The method is parameterized with the generic parameters T and N. It takes an argument of type T and returns a reference of type N.

The return type is not <T,N>, it is just N.

Upvotes: 0

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