gistfile1.java

package sample;

import java.util.Arrays;

import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;

public abstract class Response<T> {

	public abstract ResponseEntity<T> asResponseEntity();

	public static DefaultResponse<Void> created() {
		return withStatus(HttpStatus.CREATED);
	}

	public static <T> DefaultResponse<T> created(T value) {
		return withStatus(HttpStatus.CREATED, value);
	}

	public static DefaultResponse<Void> withStatus(HttpStatus status) {
		return withStatus(status, (Void) null);
	}

	public static <T> DefaultResponse<T> withStatus(HttpStatus status, T body) {
		return new DefaultResponse<T>(status, body);
	}

	public static class DefaultResponse<T> extends Response<T> {

		private final HeadersResponse<T> headers = new HeadersResponse<T>(this);

		private final HttpStatus status;

		private final T body;

		public DefaultResponse(HttpStatus status, T body) {
			this.status = status;
			this.body = body;
		}

		@Override
		public ResponseEntity<T> asResponseEntity() {
			return new ResponseEntity<T>(this.body, this.headers.headers(), this.status);
		}

		public HeadersResponse<T> withHeaders() {
			return this.headers;
		}

	}

	public static class HeadersResponse<T> extends Response<T> {

		private DefaultResponse<T> response;

		private HttpHeaders headers;

		public HeadersResponse(DefaultResponse<T> response) {
			this.response = response;
			this.headers = new HttpHeaders();
		}

		@Override
		public ResponseEntity<T> asResponseEntity() {
			return and().asResponseEntity();
		}

		protected HttpHeaders headers() {
			return this.headers;
		}

		public DefaultResponse<T> and() {
			return this.response;
		}

		public HeadersResponse<T> accepts(MediaType... mediaTypes) {
			this.headers.setAccept(Arrays.asList(mediaTypes));
			return this;
		}

		public <C> C locationFromController(Class<C> controllerClass) {
			// return a proxy here
			return null;
		}

	}
}