gistfile1.java

package match.restfulmobile.services;

import org.springframework.http.*;

import java.net.URI;
import java.util.Set;

/**
 * @author nyilmaz
 */
public class ResponseEntityBuilder {
   private ResponseEntityBuilder() {
   }

   /**
    * Creates a new {@code ResponseEntityBuilder} with the given status.
    * @param status the response status
    * @return the new response entity builder
    */
   public static ResponseBodyBuilder status(HttpStatus status) {
      return new DefaultResponseBuilder(status);
   }

   /**
    * Creates a new {@code ResponseEntityBuilder} with the given status.
    * @param status the response status
    * @return the new response entity builder
    */
   public static ResponseBodyBuilder status(int status) {
      return status(HttpStatus.valueOf(status));
   }

   /**
    * Creates a new {@code ResponseEntityBuilder} with the status set to
    * {@linkplain HttpStatus#OK OK}.
    * @return the new response entity builder
    */
   public static ResponseBodyBuilder ok() {
      return status(HttpStatus.OK);
   }

   /**
    * Creates a new {@code ResponseEntity} with the given body and the status set to
    * {@linkplain HttpStatus#OK OK}.
    * @return the new response entity
    */
   public static ResponseHeadersBuilder ok(Object body) {
      ResponseBodyBuilder builder = ok();
      builder.body(body);
      return builder;
   }

   /**
    * Creates a new {@code ResponseEntityBuilder} with a
    * {@linkplain HttpStatus#CREATED CREATED} status and a location header set to the
    * given URI.
    * @param location the location URI
    * @return the new response entity builder
    */
   public static ResponseBodyBuilder created(URI location) {
      ResponseBodyBuilder builder = status(HttpStatus.CREATED);
      return builder.location(location);
   }

   /**
    * Creates a new {@code ResponseEntityBuilder} with an
    * {@link HttpStatus#ACCEPTED ACCEPTED} status.
    * @return the new response entity builder
    */
   public static ResponseBodyBuilder accepted() {
      return status(HttpStatus.ACCEPTED);
   }

   /**
    * Creates a new {@code ResponseEntityBuilder} with an
    * {@link HttpStatus#NO_CONTENT NO_CONTENT} status.
    * @return the new response entity builder
    */
   public static ResponseHeadersBuilder noContent() {
      return status(HttpStatus.NO_CONTENT);
   }


   /**
    * Defines a builder that adds headers to the response entity.
    * @param <B> the builder subclass
    */
   public interface ResponseHeadersBuilder<B extends ResponseHeadersBuilder<B>> {

      /**
       * Add the given, single header value under the given name.
       * @param headerName  the header name
       * @param headerValues the header value(s)
       * @return this builder
       * @see HttpHeaders#add(String, String)
       */
      B header(String headerName, String... headerValues);

      /**
       * Set the set of allowed {@link HttpMethod HTTP methods}, as specified by the
       * {@code Allow} header.
       * @param allowedMethods the allowed methods
       * @see HttpHeaders#setAllow(Set)
       */
      B allow(Set<HttpMethod> allowedMethods);

      /**
       * Sets the entity tag of the body, as specified by the {@code ETag} header.
       * @param eTag the new entity tag
       * @see HttpHeaders#setETag(String)
       */
      B eTag(String eTag);

      /**
       * Sets the time the resource was last changed, as specified by the
       * {@code Last-Modified} header.
       * <p>The date should be specified as the number of milliseconds since January 1, 1970 GMT.
       * @param lastModified the last modified date
       * @see HttpHeaders#setLastModified(long)
       */
      B lastModified(long lastModified);

      /**
       * Set the location of a resource, as specified by the {@code Location} header.
       * @param location the location
       * @see HttpHeaders#setLocation(URI)
       */
      B location(URI location);

      /**
       * Builds the response entity.
       * @return the response entity
       * @see ResponseBodyBuilder#body(Object)
       */
      ResponseEntity<?> build();

   }


   /**
    * Defines a builder that adds a body to the response entity.
    */
   public interface ResponseBodyBuilder extends ResponseHeadersBuilder<ResponseBodyBuilder> {

      /**
       * Set the length of the body in bytes, as specified by the {@code Content-Length}
       * header.
       * @param contentLength the content length
       * @see HttpHeaders#setContentLength(long)
       */
      ResponseBodyBuilder contentLength(long contentLength);

      /**
       * Set the {@linkplain MediaType media type} of the body, as specified by the
       * {@code Content-Type} header.
       * @param contentType the content type
       * @see HttpHeaders#setContentType(MediaType)
       */
      ResponseBodyBuilder contentType(MediaType contentType);

      /**
       * Sets the body of the response entity and returns it.
       * @param body the body of the response entity
       * @param <T> the type of the body
       * @return the built response entity
       */
      <T> ResponseEntity<T> body(T body);

   }

   private static class DefaultResponseBuilder implements ResponseBodyBuilder {

      private final HttpStatus status;

      private final HttpHeaders headers = new HttpHeaders();

      private Object body = null;

      public DefaultResponseBuilder(HttpStatus status) {
         this.status = status;
      }

      @Override
      public ResponseBodyBuilder header(String headerName, String... headerValues) {
         for (String headerValue : headerValues) {
            headers.add(headerName, headerValue);
         }
         return this;
      }

      @Override
      public ResponseBodyBuilder allow(Set<HttpMethod> allowedMethods) {
         headers.setAllow(allowedMethods);
         return this;
      }

      @Override
      public ResponseBodyBuilder contentLength(long contentLength) {
         headers.setContentLength(contentLength);
         return this;
      }

      @Override
      public ResponseBodyBuilder contentType(MediaType contentType) {
         headers.setContentType(contentType);
         return this;
      }

      @Override
      public ResponseBodyBuilder eTag(String eTag) {
         headers.setETag(eTag);
         return this;
      }

      @Override
      public ResponseBodyBuilder lastModified(long date) {
         headers.setLastModified(date);
         return this;
      }

      @Override
      public ResponseBodyBuilder location(URI location) {
         headers.setLocation(location);
         return this;
      }


      @Override
      @SuppressWarnings("unchecked")
      public ResponseEntity<?> build() {
         return new ResponseEntity(body, headers, status);
      }

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

   }
}