Closing over immutable variable and accumulate values across multiple iterations as a lambda expression - Java 8

Question

WebTarget in Jersey client is implemented as a immutable object, and any operations to change the state returns a new WebTarget. To add query params to it, which is coming in as

Answer 1

You can use the ol' array trick, which is not good for anything more than a proof of concept.

WebTarget[] webTarget = {client.target(this.address.getUrl()).path(path)};
if (queryMap != null){
    queryMap.forEach((k, v)->{
        webTarget[0] =  webTarget[0].queryParam(k, v);
    });
}
return webTarget[0];

You could improve it by using an AtomicReference.

AtomicReference webTarget = new AtomicReference<>(client.target(this.address.getUrl()).path(path));
if (queryMap != null){
    queryMap.forEach((k, v)->{
        webTarget.updateAndGet(w->w.queryParam(k, v));
    });
}
return webTarget.get();