Java Code Examples for org.apache.olingo.server.api.uri.UriInfoResource#getUriResourceParts()

The following examples show how to use org.apache.olingo.server.api.uri.UriInfoResource#getUriResourceParts() . You can vote up the ones you like or vote down the ones you don't like, and go to the original project or source file by following the links above each example. You may check out the related API usage on the sidebar.
Example 1
Source File: CarsProcessor.java    From olingo-odata4 with Apache License 2.0 6 votes vote down vote up
private EdmEntitySet getEdmEntitySet(final UriInfoResource uriInfo) throws ODataApplicationException {
  final List<UriResource> resourcePaths = uriInfo.getUriResourceParts();
  /*
   * To get the entity set we have to interpret all URI segments
   */
  if (!(resourcePaths.get(0) instanceof UriResourceEntitySet)) {
    throw new ODataApplicationException("Invalid resource type for first segment.",
        HttpStatusCode.NOT_IMPLEMENTED.getStatusCode(), Locale.ENGLISH);
  }

  /*
   * Here we should interpret the whole URI but in this example we do not support navigation so we throw an exception
   */

  final UriResourceEntitySet uriResource = (UriResourceEntitySet) resourcePaths.get(0);
  return uriResource.getEntitySet();
}
 
Example 2
Source File: Util.java    From olingo-odata4 with Apache License 2.0 5 votes vote down vote up
public static EdmEntitySet getEdmEntitySet(UriInfoResource uriInfo) throws ODataApplicationException {
	List<UriResource> resourcePaths = uriInfo.getUriResourceParts();
	 // To get the entity set we have to interpret all URI segments
	if (!(resourcePaths.get(0) instanceof UriResourceEntitySet)) {
		// Here we should interpret the whole URI but in this example we do not support navigation so we throw an exception
		throw new ODataApplicationException("Invalid resource type for first segment.", HttpStatusCode.NOT_IMPLEMENTED.getStatusCode(),Locale.ENGLISH);
	}
	
	UriResourceEntitySet uriResource = (UriResourceEntitySet) resourcePaths.get(0);
	
	return uriResource.getEntitySet();
}
 
Example 3
Source File: Util.java    From olingo-odata4 with Apache License 2.0 5 votes vote down vote up
public static EdmEntitySet getEdmEntitySet(UriInfoResource uriInfo) throws ODataApplicationException {

    List<UriResource> resourcePaths = uriInfo.getUriResourceParts();
    // To get the entity set we have to interpret all URI segments
    if (!(resourcePaths.get(0) instanceof UriResourceEntitySet)) {
      // Here we should interpret the whole URI but in this example we do not support navigation so we throw an
      // exception
      throw new ODataApplicationException("Invalid resource type for first segment.", HttpStatusCode.NOT_IMPLEMENTED
          .getStatusCode(), Locale.ENGLISH);
    }

    UriResourceEntitySet uriResource = (UriResourceEntitySet) resourcePaths.get(0);

    return uriResource.getEntitySet();
  }
 
Example 4
Source File: Util.java    From olingo-odata4 with Apache License 2.0 5 votes vote down vote up
public static EdmEntitySet getEdmEntitySet(UriInfoResource uriInfo) throws ODataApplicationException {

    List<UriResource> resourcePaths = uriInfo.getUriResourceParts();
    // To get the entity set we have to interpret all URI segments
    if (!(resourcePaths.get(0) instanceof UriResourceEntitySet)) {
      // Here we should interpret the whole URI but in this example we do not support navigation so we throw an
      // exception
      throw new ODataApplicationException("Invalid resource type for first segment.", HttpStatusCode.NOT_IMPLEMENTED
          .getStatusCode(), Locale.ENGLISH);
    }

    UriResourceEntitySet uriResource = (UriResourceEntitySet) resourcePaths.get(0);

    return uriResource.getEntitySet();
  }
 
Example 5
Source File: Util.java    From olingo-odata4 with Apache License 2.0 5 votes vote down vote up
public static EdmEntitySet getEdmEntitySet(UriInfoResource uriInfo) throws ODataApplicationException {

    List<UriResource> resourcePaths = uriInfo.getUriResourceParts();
    // To get the entity set we have to interpret all URI segments
    if (!(resourcePaths.get(0) instanceof UriResourceEntitySet)) {
      // Here we should interpret the whole URI but in this example we do not support navigation so we throw an
      // exception
      throw new ODataApplicationException("Invalid resource type for first segment.", HttpStatusCode.NOT_IMPLEMENTED
          .getStatusCode(), Locale.ENGLISH);
    }

    UriResourceEntitySet uriResource = (UriResourceEntitySet) resourcePaths.get(0);

    return uriResource.getEntitySet();
  }
 
Example 6
Source File: Util.java    From olingo-odata4 with Apache License 2.0 5 votes vote down vote up
public static EdmEntitySet getEdmEntitySet(UriInfoResource uriInfo) throws ODataApplicationException {

    List<UriResource> resourcePaths = uriInfo.getUriResourceParts();
    // To get the entity set we have to interpret all URI segments
    if (!(resourcePaths.get(0) instanceof UriResourceEntitySet)) {
      // Here we should interpret the whole URI but in this example we do not support navigation so we throw an
      // exception
      throw new ODataApplicationException("Invalid resource type for first segment.", HttpStatusCode.NOT_IMPLEMENTED
          .getStatusCode(), Locale.ENGLISH);
    }

    UriResourceEntitySet uriResource = (UriResourceEntitySet) resourcePaths.get(0);

    return uriResource.getEntitySet();
  }
 
Example 7
Source File: Util.java    From olingo-odata4 with Apache License 2.0 5 votes vote down vote up
public static EdmEntitySet getEdmEntitySet(UriInfoResource uriInfo) throws ODataApplicationException {

    List<UriResource> resourcePaths = uriInfo.getUriResourceParts();
    // To get the entity set we have to interpret all URI segments
    if (!(resourcePaths.get(0) instanceof UriResourceEntitySet)) {
      // Here we should interpret the whole URI but in this example we do not support navigation so we throw an
      // exception
      throw new ODataApplicationException("Invalid resource type for first segment.", HttpStatusCode.NOT_IMPLEMENTED
          .getStatusCode(), Locale.ENGLISH);
    }

    UriResourceEntitySet uriResource = (UriResourceEntitySet) resourcePaths.get(0);

    return uriResource.getEntitySet();
  }
 
Example 8
Source File: Util.java    From olingo-odata4 with Apache License 2.0 5 votes vote down vote up
public static EdmEntitySet getEdmEntitySet(UriInfoResource uriInfo) throws ODataApplicationException {

    List<UriResource> resourcePaths = uriInfo.getUriResourceParts();
    // To get the entity set we have to interpret all URI segments
    if (!(resourcePaths.get(0) instanceof UriResourceEntitySet)) {
      // Here we should interpret the whole URI but in this example we do not support navigation so we throw an
      // exception
      throw new ODataApplicationException("Invalid resource type for first segment.", HttpStatusCode.NOT_IMPLEMENTED
          .getStatusCode(), Locale.ENGLISH);
    }

    UriResourceEntitySet uriResource = (UriResourceEntitySet) resourcePaths.get(0);

    return uriResource.getEntitySet();
  }
 
Example 9
Source File: Util.java    From olingo-odata4 with Apache License 2.0 5 votes vote down vote up
public static EdmEntitySet getEdmEntitySet(UriInfoResource uriInfo) throws ODataApplicationException {

    List<UriResource> resourcePaths = uriInfo.getUriResourceParts();
    // To get the entity set we have to interpret all URI segments
    if (!(resourcePaths.get(0) instanceof UriResourceEntitySet)) {
      // Here we should interpret the whole URI but in this example we do not support navigation so we throw an
      // exception
      throw new ODataApplicationException("Invalid resource type for first segment.", HttpStatusCode.NOT_IMPLEMENTED
          .getStatusCode(), Locale.ENGLISH);
    }

    UriResourceEntitySet uriResource = (UriResourceEntitySet) resourcePaths.get(0);

    return uriResource.getEntitySet();
  }
 
Example 10
Source File: Util.java    From olingo-odata4 with Apache License 2.0 5 votes vote down vote up
public static EdmEntitySet getEdmEntitySet(UriInfoResource uriInfo) throws ODataApplicationException {

    List<UriResource> resourcePaths = uriInfo.getUriResourceParts();
    // To get the entity set we have to interpret all URI segments
    if (!(resourcePaths.get(0) instanceof UriResourceEntitySet)) {
      // Here we should interpret the whole URI but in this example we do not support navigation so we throw an
      // exception
      throw new ODataApplicationException("Invalid resource type for first segment.", HttpStatusCode.NOT_IMPLEMENTED
          .getStatusCode(), Locale.ENGLISH);
    }

    UriResourceEntitySet uriResource = (UriResourceEntitySet) resourcePaths.get(0);

    return uriResource.getEntitySet();
  }
 
Example 11
Source File: Util.java    From syndesis with Apache License 2.0 5 votes vote down vote up
public static EdmEntitySet getEdmEntitySet(UriInfoResource uriInfo) throws ODataApplicationException {
    List<UriResource> resourcePaths = uriInfo.getUriResourceParts();
    // To get the entity set we have to interpret all URI segments
    if (!(resourcePaths.get(0) instanceof UriResourceEntitySet)) {
        // Here we should interpret the whole URI but in this example we do not support navigation so we throw an
        // exception
        throw new ODataApplicationException("Invalid resource type for first segment.",
                                            HttpStatusCode.NOT_IMPLEMENTED.getStatusCode(), Locale.ENGLISH);
    }

    UriResourceEntitySet uriResource = (UriResourceEntitySet)resourcePaths.get(0);

    return uriResource.getEntitySet();
}
 
Example 12
Source File: DataRequest.java    From olingo-odata4 with Apache License 2.0 5 votes vote down vote up
static ContextURL.Builder buildEntitySetContextURL(UriHelper helper,
    EdmBindingTarget edmEntitySet, List<UriParameter> keyPredicates, UriInfo uriInfo,
    LinkedList<UriResourceNavigation> navigations, boolean collectionReturn, boolean singleton, ODataRequest request)
    throws SerializerException {

  ContextURL.Builder builder =
      ContextURL.with().entitySetOrSingletonOrType(getTargetEntitySet(edmEntitySet, navigations));
  String select = helper.buildContextURLSelectList(edmEntitySet.getEntityType(),
      uriInfo.getExpandOption(), uriInfo.getSelectOption());
  if (!singleton) {
    builder.suffix(collectionReturn ? null : Suffix.ENTITY);
  }

  setServiceRoot(builder, request);    
  builder.selectList(select);

  final UriInfoResource resource = uriInfo.asUriInfoResource();
  final List<UriResource> resourceParts = resource.getUriResourceParts();
  final List<String> path = getPropertyPath(resourceParts);
  String propertyPath = buildPropertyPath(path);
  final String navPath = buildNavPath(helper, edmEntitySet.getEntityType(), navigations, collectionReturn);
  if (navPath != null && !navPath.isEmpty()) {
    if (keyPredicates != null) {
      builder.keyPath(helper.buildContextURLKeyPredicate(keyPredicates));
    }
    if (propertyPath != null) {
      propertyPath = navPath+"/"+propertyPath;
    } else {
      propertyPath = navPath;
    }
  }
  builder.navOrPropertyPath(propertyPath);
  return builder;
}
 
Example 13
Source File: TechnicalProcessor.java    From olingo-odata4 with Apache License 2.0 5 votes vote down vote up
protected UriResourceNavigation getLastNavigation(final UriInfoResource uriInfo) {
  final List<UriResource> resourcePaths = uriInfo.getUriResourceParts();
  int navigationCount = 1;
  while (navigationCount < resourcePaths.size()
      && resourcePaths.get(navigationCount) instanceof UriResourceNavigation) {
    navigationCount++;
  }
  
  final UriResource lastSegment = resourcePaths.get(--navigationCount);
  return (lastSegment instanceof UriResourceNavigation) ? (UriResourceNavigation) lastSegment : null;
}
 
Example 14
Source File: TechnicalPrimitiveComplexProcessor.java    From olingo-odata4 with Apache License 2.0 5 votes vote down vote up
private void validatePath(final UriInfoResource uriInfo) throws ODataApplicationException {
  final List<UriResource> resourcePaths = uriInfo.getUriResourceParts();
  for (final UriResource segment : resourcePaths.subList(1, resourcePaths.size())) {
    final UriResourceKind kind = segment.getKind();
    if (kind != UriResourceKind.navigationProperty
        && kind != UriResourceKind.primitiveProperty
        && kind != UriResourceKind.complexProperty
        && kind != UriResourceKind.count
        && kind != UriResourceKind.value
        && kind != UriResourceKind.function) {
      throw new ODataApplicationException("Invalid resource type.",
          HttpStatusCode.NOT_IMPLEMENTED.getStatusCode(), Locale.ROOT);
    }
  }
}
 
Example 15
Source File: TechnicalPrimitiveComplexProcessor.java    From olingo-odata4 with Apache License 2.0 5 votes vote down vote up
private void deleteProperty(final ODataRequest request, ODataResponse response, final UriInfo uriInfo,
    final boolean isValue) throws ODataLibraryException, ODataApplicationException {
  final UriInfoResource resource = uriInfo.asUriInfoResource();
  validatePath(resource);
  getEdmEntitySet(uriInfo); // including checks

  Entity entity = readEntity(uriInfo);
  odata.createETagHelper().checkChangePreconditions(entity.getETag(),
      request.getHeaders(HttpHeader.IF_MATCH),
      request.getHeaders(HttpHeader.IF_NONE_MATCH));

  final List<UriResource> resourceParts = resource.getUriResourceParts();
  final int trailing = isValue ? 1 : 0;
  final List<String> path = getPropertyPath(resourceParts, trailing);

  Property property = getPropertyData(entity, path);

  final EdmProperty edmProperty = ((UriResourceProperty) resourceParts.get(resourceParts.size() - trailing - 1))
      .getProperty();

  if (edmProperty.isNullable()) {
    property.setValue(property.getValueType(), edmProperty.isCollection() ? Collections.emptyList() : null);
    dataProvider.updateETag(entity);
    response.setStatusCode(HttpStatusCode.NO_CONTENT.getStatusCode());
    if (entity.getETag() != null) {
      response.setHeader(HttpHeader.ETAG, entity.getETag());
    }
  } else {
    throw new ODataApplicationException("Not nullable.", HttpStatusCode.BAD_REQUEST.getStatusCode(), Locale.ROOT);
  }
}
 
Example 16
Source File: TechnicalProcessor.java    From olingo-odata4 with Apache License 2.0 4 votes vote down vote up
protected List<DeltaLink> readDeletedLinks(final UriInfoResource uriInfo) throws ODataApplicationException {
  final List<UriResource> resourcePaths = uriInfo.getUriResourceParts();
  return dataProvider.readDeletedLinks(((UriResourceEntitySet) resourcePaths.get(0)).getEntitySet());
}
 
Example 17
Source File: TechnicalProcessor.java    From olingo-odata4 with Apache License 2.0 4 votes vote down vote up
protected List<DeltaLink> readAddedLinks(final UriInfoResource uriInfo) throws ODataApplicationException {
  final List<UriResource> resourcePaths = uriInfo.getUriResourceParts();
  return dataProvider.readAddedLinks(((UriResourceEntitySet) resourcePaths.get(0)).getEntitySet());
}
 
Example 18
Source File: TechnicalProcessor.java    From olingo-odata4 with Apache License 2.0 4 votes vote down vote up
protected List<DeletedEntity> readDeletedEntities(final UriInfoResource uriInfo) throws ODataApplicationException {
  final List<UriResource> resourcePaths = uriInfo.getUriResourceParts();
  return dataProvider.readDeletedEntities(((UriResourceEntitySet) resourcePaths.get(0)).getEntitySet());
}
 
Example 19
Source File: TechnicalPrimitiveComplexProcessor.java    From olingo-odata4 with Apache License 2.0 4 votes vote down vote up
private void updateProperty(final ODataRequest request, ODataResponse response, final UriInfo uriInfo,
    final ContentType requestFormat, final ContentType responseFormat, final RepresentationType representationType)
    throws ODataApplicationException, ODataLibraryException {
  final UriInfoResource resource = uriInfo.asUriInfoResource();
  validatePath(resource);
  final EdmEntitySet edmEntitySet = getEdmEntitySet(resource);

  Entity entity = readEntity(uriInfo);
  odata.createETagHelper().checkChangePreconditions(entity.getETag(),
      request.getHeaders(HttpHeader.IF_MATCH),
      request.getHeaders(HttpHeader.IF_NONE_MATCH));

  final List<UriResource> resourceParts = resource.getUriResourceParts();
  final int trailing = representationType == RepresentationType.VALUE ? 1 : 0;
  final List<String> path = getPropertyPath(resourceParts, trailing);
  final EdmProperty edmProperty = ((UriResourceProperty) resourceParts.get(resourceParts.size() - trailing - 1))
      .getProperty();

  Property property = getPropertyData(entity, path);

  if (representationType == RepresentationType.VALUE || 
  		edmProperty.getType().getFullQualifiedName()
  		.getFullQualifiedNameAsString().equalsIgnoreCase(EDMSTREAM)) {
    final FixedFormatDeserializer deserializer = odata.createFixedFormatDeserializer();
    final Object value = edmProperty.getType() == odata.createPrimitiveTypeInstance(EdmPrimitiveTypeKind.Binary) 
  		  || edmProperty.getType() == odata.createPrimitiveTypeInstance(EdmPrimitiveTypeKind.Stream) ?
        deserializer.binary(request.getBody()) :
        deserializer.primitiveValue(request.getBody(), edmProperty);
    dataProvider.updatePropertyValue(property, value);
  } else {
    final Property changedProperty = odata.createDeserializer(requestFormat)
        .property(request.getBody(), edmProperty).getProperty();
    if (changedProperty.isNull() && !edmProperty.isNullable()) {
      throw new ODataApplicationException("Not nullable.", HttpStatusCode.BAD_REQUEST.getStatusCode(), Locale.ROOT);
    }
    dataProvider.updateProperty(edmProperty, property, changedProperty, request.getMethod() == HttpMethod.PATCH);
  }

  dataProvider.updateETag(entity);

  final Return returnPreference = odata.createPreferences(request.getHeaders(HttpHeader.PREFER)).getReturn();
  if (returnPreference == null || returnPreference == Return.REPRESENTATION) {
    response.setStatusCode(HttpStatusCode.OK.getStatusCode());
    if (representationType == RepresentationType.VALUE || 
      		edmProperty.getType().getFullQualifiedName()
        		.getFullQualifiedNameAsString().equalsIgnoreCase(EDMSTREAM)) {
      response.setContent(
          serializePrimitiveValue(property, edmProperty, (EdmPrimitiveType) edmProperty.getType(), null));
    } else {
      final SerializerResult result = serializeProperty(entity, edmEntitySet, path, property, edmProperty,
          edmProperty.getType(), null, representationType, responseFormat, null, null);
      response.setContent(result.getContent());
    }
    if (edmProperty.getType().getFullQualifiedName()
      		.getFullQualifiedNameAsString().equalsIgnoreCase(EDMSTREAM)) {
    	  response.setHeader(HttpHeader.CONTENT_TYPE, requestFormat.toContentTypeString());
      } else {
    	  response.setHeader(HttpHeader.CONTENT_TYPE, responseFormat.toContentTypeString());
      }
  } else {
    response.setStatusCode(HttpStatusCode.NO_CONTENT.getStatusCode());
  }
  if (returnPreference != null) {
    response.setHeader(HttpHeader.PREFERENCE_APPLIED,
        PreferencesApplied.with().returnRepresentation(returnPreference).build().toValueString());
  }
  if (entity.getETag() != null) {
    response.setHeader(HttpHeader.ETAG, entity.getETag());
  }
}
 
Example 20
Source File: TechnicalPrimitiveComplexProcessor.java    From olingo-odata4 with Apache License 2.0 4 votes vote down vote up
private void readProperty(final ODataRequest request, ODataResponse response, final UriInfo uriInfo,
    final ContentType contentType, final RepresentationType representationType)
        throws ODataApplicationException, ODataLibraryException {
  final UriInfoResource resource = uriInfo.asUriInfoResource();
  validateOptions(resource);
  validatePath(resource);
  final EdmEntitySet edmEntitySet = getEdmEntitySet(resource);

  final List<UriResource> resourceParts = resource.getUriResourceParts();
  final int trailing =
      representationType == RepresentationType.COUNT || representationType == RepresentationType.VALUE ? 1 : 0;
  final List<String> path = getPropertyPath(resourceParts, trailing);

  final Entity entity = readEntity(uriInfo);

  if (entity != null && entity.getETag() != null) {
    if (odata.createETagHelper().checkReadPreconditions(entity.getETag(),
        request.getHeaders(HttpHeader.IF_MATCH),
        request.getHeaders(HttpHeader.IF_NONE_MATCH))) {
      response.setStatusCode(HttpStatusCode.NOT_MODIFIED.getStatusCode());
      response.setHeader(HttpHeader.ETAG, entity.getETag());
      return;
    }
  }

  final Property property = entity == null ?
      getPropertyData(
          dataProvider.readFunctionPrimitiveComplex(((UriResourceFunction) resourceParts.get(0)).getFunction(),
          ((UriResourceFunction) resourceParts.get(0)).getParameters(), resource), path) :
      getData(entity, path, resourceParts, resource);

  // TODO: implement filter on collection properties (on a shallow copy of the values)
  // FilterHandler.applyFilterSystemQuery(uriInfo.getFilterOption(), property, uriInfo, serviceMetadata.getEdm());

  if (property == null && representationType != RepresentationType.COUNT) {
    if (representationType == RepresentationType.VALUE) {
      response.setStatusCode(HttpStatusCode.NO_CONTENT.getStatusCode());
    } else {
      throw new ODataApplicationException("Nothing found.", HttpStatusCode.NOT_FOUND.getStatusCode(), Locale.ROOT);
    }
  } else {
    if (property.getValue() == null && representationType != RepresentationType.COUNT) {
      response.setStatusCode(HttpStatusCode.NO_CONTENT.getStatusCode());
    } else {
      response.setStatusCode(HttpStatusCode.OK.getStatusCode());
      if (representationType == RepresentationType.COUNT) {
        response.setContent(odata.createFixedFormatSerializer().count(
            property.asCollection().size()));
      } else {
        final EdmProperty edmProperty = path.isEmpty() ? null :
            ((UriResourceProperty) resourceParts.get(resourceParts.size() - trailing - 1)).getProperty();
        EdmType type = null;
        if (resourceParts.get(resourceParts.size() - trailing - 1) 
           instanceof UriResourceComplexProperty &&
            ((UriResourceComplexProperty)resourceParts.get(resourceParts.size() - trailing - 1)).
            getComplexTypeFilter() != null) {
          type = ((UriResourceComplexProperty)resourceParts.get(resourceParts.size() - trailing - 1)).
              getComplexTypeFilter();
        }else if(resourceParts.get(resourceParts.size() - trailing - 1) 
           instanceof UriResourceFunction &&
            ((UriResourceFunction)resourceParts.get(resourceParts.size() - trailing - 1)).
            getFunction() != null){ 
          type = ((UriResourceFunction)resourceParts.get(resourceParts.size() - trailing - 1)).
              getType();
        }else {
          type = edmProperty == null ?
              ((UriResourceFunction) resourceParts.get(0)).getType() :
              edmProperty.getType();
        }
        final EdmReturnType returnType = resourceParts.get(0) instanceof UriResourceFunction ?
            ((UriResourceFunction) resourceParts.get(0)).getFunction().getReturnType() : 
              resourceParts.get(1) instanceof UriResourceFunction ? 
                  ((UriResourceFunction) resourceParts.get(1)).getFunction().getReturnType():null ;

        if (representationType == RepresentationType.VALUE) {
          response.setContent(serializePrimitiveValue(property, edmProperty, (EdmPrimitiveType) type, returnType));
        }else if(representationType == RepresentationType.PRIMITIVE && type.getFullQualifiedName()
            .getFullQualifiedNameAsString().equals(EDMSTREAM)){
          response.setContent(odata.createFixedFormatSerializer().binary(dataProvider.readStreamProperty(property)));
          response.setStatusCode(HttpStatusCode.OK.getStatusCode());
          response.setHeader(HttpHeader.CONTENT_TYPE, ((Link)property.getValue()).getType());
          if (entity.getMediaETag() != null) {
            response.setHeader(HttpHeader.ETAG, entity.getMediaETag());
          }
        }else {
          final ExpandOption expand = uriInfo.getExpandOption();
          final SelectOption select = uriInfo.getSelectOption();
          final SerializerResult result = serializeProperty(entity, edmEntitySet, path, property, edmProperty,
              type, returnType, representationType, contentType, expand, select);
          response.setContent(result.getContent());
        }
      }
      response.setHeader(HttpHeader.CONTENT_TYPE, contentType.toContentTypeString());
    }
    if (entity != null && entity.getETag() != null) {
      response.setHeader(HttpHeader.ETAG, entity.getETag());
    }
  }
}