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

public void deleteEntity(ODataRequest request, ODataResponse response, UriInfo uriInfo)
         throws ODataApplicationException {
	
	// 1. Retrieve the entity set which belongs to the requested entity 
	List<UriResource> resourcePaths = uriInfo.getUriResourceParts();
	// Note: only in our example we can assume that the first segment is the EntitySet
	UriResourceEntitySet uriResourceEntitySet = (UriResourceEntitySet) resourcePaths.get(0); 
	EdmEntitySet edmEntitySet = uriResourceEntitySet.getEntitySet();

	// 2. delete the data in backend
	List<UriParameter> keyPredicates = uriResourceEntitySet.getKeyPredicates();
	storage.deleteEntityData(edmEntitySet, keyPredicates);
	
	//3. configure the response object
	response.setStatusCode(HttpStatusCode.NO_CONTENT.getStatusCode());
}
 

public void updateEntity(ODataRequest request, ODataResponse response, UriInfo uriInfo,
                          ContentType requestFormat, ContentType responseFormat)
						throws ODataApplicationException, DeserializerException, SerializerException {
	
	// 1. Retrieve the entity set which belongs to the requested entity 
	List<UriResource> resourcePaths = uriInfo.getUriResourceParts();
	// Note: only in our example we can assume that the first segment is the EntitySet
	UriResourceEntitySet uriResourceEntitySet = (UriResourceEntitySet) resourcePaths.get(0); 
	EdmEntitySet edmEntitySet = uriResourceEntitySet.getEntitySet();
	EdmEntityType edmEntityType = edmEntitySet.getEntityType();

	// 2. update the data in backend
	// 2.1. retrieve the payload from the PUT request for the entity to be updated 
	InputStream requestInputStream = request.getBody();
	ODataDeserializer deserializer = odata.createDeserializer(requestFormat);
	DeserializerResult result = deserializer.entity(requestInputStream, edmEntityType);
	Entity requestEntity = result.getEntity();
	// 2.2 do the modification in backend
	List<UriParameter> keyPredicates = uriResourceEntitySet.getKeyPredicates();
	// Note that this updateEntity()-method is invoked for both PUT or PATCH operations
	HttpMethod httpMethod = request.getMethod();
	storage.updateEntityData(edmEntitySet, keyPredicates, requestEntity, httpMethod);
	
	//3. configure the response object
	response.setStatusCode(HttpStatusCode.NO_CONTENT.getStatusCode());
}
 

public void deleteEntity(ODataRequest request, ODataResponse response, UriInfo uriInfo)
         throws ODataApplicationException {
	
	// 1. Retrieve the entity set which belongs to the requested entity 
	List<UriResource> resourcePaths = uriInfo.getUriResourceParts();
	// Note: only in our example we can assume that the first segment is the EntitySet
	UriResourceEntitySet uriResourceEntitySet = (UriResourceEntitySet) resourcePaths.get(0); 
	EdmEntitySet edmEntitySet = uriResourceEntitySet.getEntitySet();

	// 2. delete the data in backend
	List<UriParameter> keyPredicates = uriResourceEntitySet.getKeyPredicates();
	storage.deleteEntityData(edmEntitySet, keyPredicates);
	
	//3. configure the response object
	response.setStatusCode(HttpStatusCode.NO_CONTENT.getStatusCode());
}
 

private boolean mustValidate(final String uri, final String entitySetName)
    throws UriParserException, UriValidationException, PreconditionException {
  final UriInfo uriInfo = new Parser(edm, odata).parseUri(uri, null, null, null);
  final List<UriResource> parts = uriInfo.getUriResourceParts();
  final boolean isMedia = parts.size() >= 2
      && parts.get(parts.size() - 1) instanceof UriResourceValue
      && parts.get(parts.size() - 2) instanceof UriResourceEntitySet;

  CustomETagSupport support = mock(CustomETagSupport.class);
  final Answer<Boolean> answer = new Answer<Boolean>() {
    public Boolean answer(final InvocationOnMock invocation) throws Throwable {
      if (entitySetName != null) {
        assertEquals(entitySetName, ((EdmBindingTarget) invocation.getArguments()[0]).getName());
      }
      return true;
    }};
  when(support.hasETag(any(EdmBindingTarget.class))).thenAnswer(answer);
  when(support.hasMediaETag(any(EdmBindingTarget.class))).thenAnswer(answer);

  return new PreconditionsValidator(uriInfo).mustValidatePreconditions(support, isMedia);
}
 

public void updateEntity(ODataRequest request, ODataResponse response, UriInfo uriInfo,
                          ContentType requestFormat, ContentType responseFormat)
						throws ODataApplicationException, DeserializerException, SerializerException {
	
	// 1. Retrieve the entity set which belongs to the requested entity 
	List<UriResource> resourcePaths = uriInfo.getUriResourceParts();
	// Note: only in our example we can assume that the first segment is the EntitySet
	UriResourceEntitySet uriResourceEntitySet = (UriResourceEntitySet) resourcePaths.get(0); 
	EdmEntitySet edmEntitySet = uriResourceEntitySet.getEntitySet();
	EdmEntityType edmEntityType = edmEntitySet.getEntityType();

	// 2. update the data in backend
	// 2.1. retrieve the payload from the PUT request for the entity to be updated 
	InputStream requestInputStream = request.getBody();
	ODataDeserializer deserializer = odata.createDeserializer(requestFormat);
	DeserializerResult result = deserializer.entity(requestInputStream, edmEntityType);
	Entity requestEntity = result.getEntity();
	// 2.2 do the modification in backend
	List<UriParameter> keyPredicates = uriResourceEntitySet.getKeyPredicates();
	// Note that this updateEntity()-method is invoked for both PUT or PATCH operations
	HttpMethod httpMethod = request.getMethod();
	storage.updateEntityData(edmEntitySet, keyPredicates, requestEntity, httpMethod);
	
	//3. configure the response object
	response.setStatusCode(HttpStatusCode.NO_CONTENT.getStatusCode());
}
 

@Override
public void deleteEntity(ODataRequest request, ODataResponse response, UriInfo uriInfo) throws ODataApplicationException {
    // 1. Retrieve the entity set which belongs to the requested entity
    List<UriResource> resourcePaths = uriInfo.getUriResourceParts();
    // Note: only in our example we can assume that the first segment is the
    // EntitySet
    UriResourceEntitySet uriResourceEntitySet = (UriResourceEntitySet) resourcePaths.get(0);
    EdmEntitySet edmEntitySet = uriResourceEntitySet.getEntitySet();

    // 2. delete the data in backend
    List<UriParameter> keyPredicates = uriResourceEntitySet.getKeyPredicates();
    for (UriParameter kp : keyPredicates) {
        LOG.info("Deleting entity {} ( {} )", kp.getName(), kp.getText());
    }

    storage.deleteEntityData(edmEntitySet, keyPredicates);

    // 3. configure the response object
    response.setStatusCode(HttpStatusCode.NO_CONTENT.getStatusCode());
}
 

public void readEntityCollection(ODataRequest request,
		ODataResponse response, UriInfo uriInfo, ContentType responseFormat)
		throws ODataApplicationException, SerializerException {

	// 1st we have retrieve the requested EntitySet from the uriInfo object
	// (representation of the parsed service URI)
	List<UriResource> resourcePaths = uriInfo.getUriResourceParts();
	UriResourceEntitySet uriResourceEntitySet = (UriResourceEntitySet) resourcePaths
			.get(0); // in our example, the first segment is the EntitySet
	EdmEntitySet edmEntitySet = uriResourceEntitySet.getEntitySet();

	// 2nd: fetch the data from backend for this requested EntitySetName //
	// it has to be delivered as EntitySet object
	EntitySet entitySet = getData(uriInfo);

	// 3rd: create a serializer based on the requested format (json)
	ODataFormat format = ODataFormat.fromContentType(responseFormat);
	ODataSerializer serializer = odata.createSerializer(format);

	// 4th: Now serialize the content: transform from the EntitySet object
	// to InputStream
	EdmEntityType edmEntityType = edmEntitySet.getEntityType();
	ContextURL contextUrl = ContextURL.with().entitySet(edmEntitySet)
			.build();

	EntityCollectionSerializerOptions opts = EntityCollectionSerializerOptions
			.with().contextURL(contextUrl).build();
	InputStream serializedContent = serializer.entityCollection(
			edmEntityType, entitySet, opts);

	// Finally: configure the response object: set the body, headers and
	// status code
	response.setContent(serializedContent);
	response.setStatusCode(HttpStatusCode.OK.getStatusCode());
	response.setHeader(HttpHeader.CONTENT_TYPE,
			responseFormat.toContentTypeString());
}
 

public void readEntityCollection(ODataRequest request, ODataResponse response, UriInfo uriInfo,
    ContentType responseFormat) throws ODataApplicationException, SerializerException {

  // 1st retrieve the requested EntitySet from the uriInfo (representation of the parsed URI)
  List<UriResource> resourcePaths = uriInfo.getUriResourceParts();
  // in our example, the first segment is the EntitySet
  UriResourceEntitySet uriResourceEntitySet = (UriResourceEntitySet) resourcePaths.get(0);
  EdmEntitySet edmEntitySet = uriResourceEntitySet.getEntitySet();

  // 2nd: fetch the data from backend for this requested EntitySetName
  // it has to be delivered as EntitySet object
  EntityCollection entitySet = storage.readEntitySetData(edmEntitySet);

  // 3rd: create a serializer based on the requested format (json)
  ODataSerializer serializer = odata.createSerializer(responseFormat);

  // and serialize the content: transform from the EntitySet object to InputStream
  EdmEntityType edmEntityType = edmEntitySet.getEntityType();
  ContextURL contextUrl = ContextURL.with().entitySet(edmEntitySet).build();

  final String id = request.getRawBaseUri() + "/" + edmEntitySet.getName();
  EntityCollectionSerializerOptions opts =
      EntityCollectionSerializerOptions.with().id(id).contextURL(contextUrl).build();
  SerializerResult serializedContent = serializer.entityCollection(serviceMetadata, edmEntityType, entitySet, opts);

  // Finally: configure the response object: set the body, headers and status code
  response.setContent(serializedContent.getContent());
  response.setStatusCode(HttpStatusCode.OK.getStatusCode());
  response.setHeader(HttpHeader.CONTENT_TYPE, responseFormat.toContentTypeString());
}
 

private boolean isContNav(UriInfo uriInfo) {
  List<UriResource> resourceParts = uriInfo.getUriResourceParts();
  for (UriResource resourcePart : resourceParts) {
    if (resourcePart instanceof UriResourceNavigation) {
      UriResourceNavigation navResource = (UriResourceNavigation) resourcePart;
      if (navResource.getProperty().containsTarget()) {
        return true;
      }
    }
  }
  return false;
}
 

public void readEntityCollection(ODataRequest request, ODataResponse response, UriInfo uriInfo, ContentType responseFormat) throws ODataApplicationException, SerializerException {

    // 1st we have retrieve the requested EntitySet from the uriInfo object (representation of the parsed service URI)
    List<UriResource> resourcePaths = uriInfo.getUriResourceParts();
    UriResourceEntitySet uriResourceEntitySet = (UriResourceEntitySet) resourcePaths.get(0); // in our example, the first segment is the EntitySet
    EdmEntitySet edmEntitySet = uriResourceEntitySet.getEntitySet();

    // 2nd: fetch the data from backend for this requested EntitySetName // it has to be delivered as EntitySet object
    EntityCollection entitySet = getData(edmEntitySet);

    // 3rd: create a serializer based on the requested format (json)
    ODataSerializer serializer = odata.createSerializer(responseFormat);
    
    // 4th: Now serialize the content: transform from the EntitySet object to InputStream
    EdmEntityType edmEntityType = edmEntitySet.getEntityType();
    ContextURL contextUrl = ContextURL.with().entitySet(edmEntitySet).build();

    final String id = request.getRawBaseUri() + "/" + edmEntitySet.getName();
    EntityCollectionSerializerOptions opts =
        EntityCollectionSerializerOptions.with().id(id).contextURL(contextUrl).build();
    SerializerResult serializedContent = serializer.entityCollection(serviceMetadata, edmEntityType, entitySet, opts);

    // Finally: configure the response object: set the body, headers and status code
    response.setContent(serializedContent.getContent());
    response.setStatusCode(HttpStatusCode.OK.getStatusCode());
    response.setHeader(HttpHeader.CONTENT_TYPE, responseFormat.toContentTypeString());
  }
 

public void readEntityCollection(ODataRequest request, ODataResponse response, UriInfo uriInfo, ContentType responseFormat) throws ODataApplicationException, SerializerException {

		// 1st retrieve the requested EntitySet from the uriInfo (representation of the parsed URI)
		List<UriResource> resourcePaths = uriInfo.getUriResourceParts();
		UriResourceEntitySet uriResourceEntitySet = (UriResourceEntitySet) resourcePaths.get(0); // in our example, the first segment is the EntitySet
		EdmEntitySet edmEntitySet = uriResourceEntitySet.getEntitySet();

		// 2nd: fetch the data from backend for this requested EntitySetName and deliver as EntitySet
		EntityCollection entityCollection = storage.readEntitySetData(edmEntitySet);

		// 3rd: create a serializer based on the requested format (json)
		ODataSerializer serializer = odata.createSerializer(responseFormat);

		// and serialize the content: transform from the EntitySet object to InputStream
		EdmEntityType edmEntityType = edmEntitySet.getEntityType();
		ContextURL contextUrl = ContextURL.with().entitySet(edmEntitySet).build();

		final String id = request.getRawBaseUri() + "/" + edmEntitySet.getName();
		EntityCollectionSerializerOptions opts =
				EntityCollectionSerializerOptions.with().id(id).contextURL(contextUrl).build();
		SerializerResult serializerResult = serializer.entityCollection(serviceMetadata, edmEntityType, entityCollection, opts);
		InputStream serializedContent = serializerResult.getContent();

		// 4th: configure the response object: set the body, headers and status code
		response.setContent(serializedContent);
		response.setStatusCode(HttpStatusCode.OK.getStatusCode());
		response.setHeader(HttpHeader.CONTENT_TYPE, responseFormat.toContentTypeString());
	}
 

public void readPrimitive(ODataRequest request, ODataResponse response, 
							UriInfo uriInfo, ContentType responseFormat) 
							throws ODataApplicationException, SerializerException {

	// 1. Retrieve info from URI
	// 1.1. retrieve the info about the requested entity set 
	List<UriResource> resourceParts = uriInfo.getUriResourceParts();
	// Note: only in our example we can rely that the first segment is the EntitySet
	UriResourceEntitySet uriEntityset = (UriResourceEntitySet) resourceParts.get(0); 
	EdmEntitySet edmEntitySet = uriEntityset.getEntitySet();
	// the key for the entity
	List<UriParameter> keyPredicates = uriEntityset.getKeyPredicates();
	
	// 1.2. retrieve the requested (Edm) property 
	UriResourceProperty uriProperty = (UriResourceProperty)resourceParts.get(resourceParts.size() -1); // the last segment is the Property
	EdmProperty edmProperty = uriProperty.getProperty();
	String edmPropertyName = edmProperty.getName();
	// in our example, we know we have only primitive types in our model
	EdmPrimitiveType edmPropertyType = (EdmPrimitiveType) edmProperty.getType(); 
	
	
	// 2. retrieve data from backend
	// 2.1. retrieve the entity data, for which the property has to be read
	Entity entity = storage.readEntityData(edmEntitySet, keyPredicates);
	if (entity == null) { // Bad request
		throw new ODataApplicationException("Entity not found",
						HttpStatusCode.NOT_FOUND.getStatusCode(), Locale.ENGLISH);
	} 
	
	// 2.2. retrieve the property data from the entity
	Property property = entity.getProperty(edmPropertyName);
	if (property == null) {
		throw new ODataApplicationException("Property not found",
             HttpStatusCode.NOT_FOUND.getStatusCode(), Locale.ENGLISH);
	}		
	
	// 3. serialize
	Object value = property.getValue();
	if (value != null) {
		// 3.1. configure the serializer
		ODataSerializer serializer = odata.createSerializer(responseFormat);
		
		ContextURL contextUrl = ContextURL.with().entitySet(edmEntitySet).navOrPropertyPath(edmPropertyName).build();
		PrimitiveSerializerOptions options = PrimitiveSerializerOptions.with().contextURL(contextUrl).build();
		// 3.2. serialize
		SerializerResult result = serializer.primitive(serviceMetadata, edmPropertyType, property, options);
		
		//4. configure the response object
		response.setContent(result.getContent());
		response.setStatusCode(HttpStatusCode.OK.getStatusCode());
		response.setHeader(HttpHeader.CONTENT_TYPE, responseFormat.toContentTypeString());		
	}else{
		// in case there's no value for the property, we can skip the serialization
		response.setStatusCode(HttpStatusCode.NO_CONTENT.getStatusCode());
	}
}
 

public void readEntityCollection(ODataRequest request, ODataResponse response,
    UriInfo uriInfo, ContentType responseFormat)
    throws ODataApplicationException, SerializerException {
  
  EdmEntitySet responseEdmEntitySet = null; // we'll need this to build the ContextURL
  EntityCollection responseEntityCollection = null; // we'll need this to set the response body

  // 1st retrieve the requested EntitySet from the uriInfo (representation of the parsed URI)
  List<UriResource> resourceParts = uriInfo.getUriResourceParts();
  int segmentCount = resourceParts.size();

  UriResource uriResource = resourceParts.get(0); // in our example, the first segment is the EntitySet
  if (!(uriResource instanceof UriResourceEntitySet)) {
    throw new ODataApplicationException("Only EntitySet is supported",
        HttpStatusCode.NOT_IMPLEMENTED.getStatusCode(), Locale.ROOT);
  }

  UriResourceEntitySet uriResourceEntitySet = (UriResourceEntitySet) uriResource;
  EdmEntitySet startEdmEntitySet = uriResourceEntitySet.getEntitySet();

  if (segmentCount == 1) { // this is the case for: DemoService/DemoService.svc/Categories
    responseEdmEntitySet = startEdmEntitySet; // the response body is built from the first (and only) entitySet

    // 2nd: fetch the data from backend for this requested EntitySetName and deliver as EntitySet
    responseEntityCollection = storage.readEntitySetData(startEdmEntitySet);
  } else if (segmentCount == 2) { // in case of navigation: DemoService.svc/Categories(3)/Products

    UriResource lastSegment = resourceParts.get(1); // in our example we don't support more complex URIs
    if (lastSegment instanceof UriResourceNavigation) {
      UriResourceNavigation uriResourceNavigation = (UriResourceNavigation) lastSegment;
      EdmNavigationProperty edmNavigationProperty = uriResourceNavigation.getProperty();
      // from Categories(1) to Products
      responseEdmEntitySet = Util.getNavigationTargetEntitySet(startEdmEntitySet, edmNavigationProperty);

      // 2nd: fetch the data from backend
      // first fetch the entity where the first segment of the URI points to
      List<UriParameter> keyPredicates = uriResourceEntitySet.getKeyPredicates();
      // e.g. for Categories(3)/Products we have to find the single entity: Category with ID 3
      Entity sourceEntity = storage.readEntityData(startEdmEntitySet, keyPredicates);
      // error handling for e.g. DemoService.svc/Categories(99)/Products
      if (sourceEntity == null) {
        throw new ODataApplicationException("Entity not found.",
            HttpStatusCode.NOT_FOUND.getStatusCode(), Locale.ROOT);
      }
      // then fetch the entity collection where the entity navigates to
      // note: we don't need to check uriResourceNavigation.isCollection(),
      // because we are the EntityCollectionProcessor
      responseEntityCollection = storage.getRelatedEntityCollection(sourceEntity, uriResourceNavigation);
    }
  } else { // this would be the case for e.g. Products(1)/Category/Products
    throw new ODataApplicationException("Not supported",
        HttpStatusCode.NOT_IMPLEMENTED.getStatusCode(), Locale.ROOT);
  }

  // 3rd: create and configure a serializer
  ContextURL contextUrl = ContextURL.with().entitySet(responseEdmEntitySet).build();
  final String id = request.getRawBaseUri() + "/" + responseEdmEntitySet.getName();
  EntityCollectionSerializerOptions opts = EntityCollectionSerializerOptions.with()
      .contextURL(contextUrl).id(id).build();
  EdmEntityType edmEntityType = responseEdmEntitySet.getEntityType();

  ODataSerializer serializer = odata.createSerializer(responseFormat);
  SerializerResult serializerResult = serializer.entityCollection(serviceMetadata, edmEntityType,
      responseEntityCollection, opts);

  // 4th: configure the response object: set the body, headers and status code
  response.setContent(serializerResult.getContent());
  response.setStatusCode(HttpStatusCode.OK.getStatusCode());
  response.setHeader(HttpHeader.CONTENT_TYPE, responseFormat.toContentTypeString());
}
 

@Override
public void readEntityCollection(ODataRequest request, ODataResponse response, UriInfo uriInfo, ContentType responseFormat)
    throws ODataApplicationException, ODataLibraryException {
    // 1st we have retrieve the requested EntitySet from the uriInfo object (representation of the parsed service URI)
    List<UriResource> resourcePaths = uriInfo.getUriResourceParts();
    UriResourceEntitySet uriResourceEntitySet = (UriResourceEntitySet)resourcePaths.get(0); // in our example, the first segment is the EntitySet
    EdmEntitySet edmEntitySet = uriResourceEntitySet.getEntitySet();

    // 2nd: fetch the data from backend for this requested EntitySetName
    // it has to be delivered as EntitySet object
    EntityCollection entityCollection = storage.readEntitySetData(edmEntitySet);

    // 3rd: apply System Query Options
    // modify the result set according to the query options, specified by the end user
    List<Entity> entityList = entityCollection.getEntities();
    EntityCollection returnEntityCollection = new EntityCollection();

    // handle $count: always return the original number of entities, without considering $top and $skip
    CountOption countOption = uriInfo.getCountOption();
    if (countOption != null) {
        boolean isCount = countOption.getValue();
        if (isCount) {
            returnEntityCollection.setCount(entityList.size());
        }
    }

    applyQueryOptions(uriInfo, entityList, returnEntityCollection);

    // 3rd: create a serializer based on the requested format (json)
    ODataSerializer serializer = odata.createSerializer(responseFormat);

    // 4th: Now serialize the content: transform from the EntitySet object to InputStream
    EdmEntityType edmEntityType = edmEntitySet.getEntityType();
    ContextURL contextUrl = ContextURL.with().entitySet(edmEntitySet).build();

    final String id = request.getRawBaseUri() + "/" + edmEntitySet.getName();
    EntityCollectionSerializerOptions opts =
        EntityCollectionSerializerOptions
            .with().id(id)
            .count(countOption)
            .contextURL(contextUrl)
            .build();

    SerializerResult serializerResult = serializer.entityCollection(serviceMetadata,
                                                                    edmEntityType,
                                                                    returnEntityCollection,
                                                                    opts);
    InputStream serializedContent = serializerResult.getContent();

    // Finally: configure the response object: set the body, headers and status code
    response.setContent(serializedContent);
    response.setStatusCode(HttpStatusCode.OK.getStatusCode());
    response.setHeader(HttpHeader.CONTENT_TYPE, responseFormat.toContentTypeString());
}
 

private EdmBindingTarget extractInformation(final UriInfo uriInfo) throws PreconditionException {
  EdmBindingTarget lastFoundEntitySetOrSingleton = null;
  int counter = 0;
  for (UriResource uriResourcePart : uriInfo.getUriResourceParts()) {
    switch (uriResourcePart.getKind()) {
    case function:
      lastFoundEntitySetOrSingleton = getEntitySetFromFunctionImport((UriResourceFunction) uriResourcePart);
      break;
    case singleton:
      lastFoundEntitySetOrSingleton = ((UriResourceSingleton) uriResourcePart).getSingleton();
      break;
    case entitySet:
      lastFoundEntitySetOrSingleton = getEntitySet((UriResourceEntitySet) uriResourcePart);
      break;
    case navigationProperty:
      lastFoundEntitySetOrSingleton = getEntitySetFromNavigation(lastFoundEntitySetOrSingleton,
          (UriResourceNavigation) uriResourcePart);
      break;
    case primitiveProperty:
    case complexProperty:
      break;
    case value:
    case action:
      // This should not be possible since the URI Parser validates this but to be sure we throw an exception.
      if (counter != uriInfo.getUriResourceParts().size() - 1) {
        throw new PreconditionException("$value or Action must be the last segment in the URI.",
            PreconditionException.MessageKeys.INVALID_URI);
      }
      break;
    default:
      lastFoundEntitySetOrSingleton = null;
      break;
    }
    if (lastFoundEntitySetOrSingleton == null) {
      // Once we loose track of the entity set there is no way to retrieve it.
      break;
    }
    counter++;
  }
  return lastFoundEntitySetOrSingleton;
}
 

public void readEntityCollection(ODataRequest request, ODataResponse response, UriInfo uriInfo, 
    ContentType responseFormat) throws ODataApplicationException, SerializerException {

	// 1st retrieve the requested EntitySet from the uriInfo (representation of the parsed URI)
	List<UriResource> resourcePaths = uriInfo.getUriResourceParts();
	// in our example, the first segment is the EntitySet
	UriResourceEntitySet uriResourceEntitySet = (UriResourceEntitySet) resourcePaths.get(0); 
	EdmEntitySet edmEntitySet = uriResourceEntitySet.getEntitySet();

	// 2nd: fetch the data from backend for this requested EntitySetName and deliver as EntitySet
	EntityCollection entityCollection = storage.readEntitySetData(edmEntitySet);
	List<Entity> entityList = entityCollection.getEntities();
	
	// 3rd apply $orderby
	OrderByOption orderByOption = uriInfo.getOrderByOption();
	if (orderByOption != null) {
		List<OrderByItem> orderItemList = orderByOption.getOrders();
		final OrderByItem orderByItem = orderItemList.get(0); // in our example we support only one
		Expression expression = orderByItem.getExpression();
		if(expression instanceof Member){
			UriInfoResource resourcePath = ((Member)expression).getResourcePath();
			UriResource uriResource = resourcePath.getUriResourceParts().get(0);
			if (uriResource instanceof UriResourcePrimitiveProperty) {
				EdmProperty edmProperty = ((UriResourcePrimitiveProperty)uriResource).getProperty();
				final String sortPropertyName = edmProperty.getName();

				// do the sorting for the list of entities  
				Collections.sort(entityList, new Comparator<Entity>() {

					// we delegate the sorting to the native sorter of Integer and String
					public int compare(Entity entity1, Entity entity2) {
						int compareResult = 0;

						if(sortPropertyName.equals("ID")){
							Integer integer1 = (Integer) entity1.getProperty(sortPropertyName).getValue();
							Integer integer2 = (Integer) entity2.getProperty(sortPropertyName).getValue();
							
							compareResult = integer1.compareTo(integer2);
						}else{
							String propertyValue1 = (String) entity1.getProperty(sortPropertyName).getValue();
							String propertyValue2 = (String) entity2.getProperty(sortPropertyName).getValue();
							
							compareResult = propertyValue1.compareTo(propertyValue2);
						}

						// if 'desc' is specified in the URI, change the order of the list 
						if(orderByItem.isDescending()){
							return - compareResult; // just convert the result to negative value to change the order
						}
						
						return compareResult;
					}
				});
			}
		}
	}
	
	
	// 4th: create a serializer based on the requested format (json)
	ODataSerializer serializer = odata.createSerializer(responseFormat);

	// and serialize the content: transform from the EntitySet object to InputStream
	EdmEntityType edmEntityType = edmEntitySet.getEntityType();
	ContextURL contextUrl = ContextURL.with().entitySet(edmEntitySet).build();

	final String id = request.getRawBaseUri() + "/" + edmEntitySet.getName();
	EntityCollectionSerializerOptions opts =
			EntityCollectionSerializerOptions.with().id(id).contextURL(contextUrl).build();
   SerializerResult serializerResult = serializer.entityCollection(serviceMetadata, edmEntityType, 
                                                                   entityCollection, opts);
	InputStream serializedContent = serializerResult.getContent();

	// 5th: configure the response object: set the body, headers and status code
	response.setContent(serializedContent);
	response.setStatusCode(HttpStatusCode.OK.getStatusCode());
	response.setHeader(HttpHeader.CONTENT_TYPE, responseFormat.toContentTypeString());
}
 

public void readPrimitive(ODataRequest request, ODataResponse response,
							UriInfo uriInfo, ContentType responseFormat)
							throws ODataApplicationException, SerializerException {

	// 1. Retrieve info from URI
	// 1.1. retrieve the info about the requested entity set
	List<UriResource> resourceParts = uriInfo.getUriResourceParts();
	// Note: only in our example we can rely that the first segment is the EntitySet
	UriResourceEntitySet uriEntityset = (UriResourceEntitySet) resourceParts.get(0);
	EdmEntitySet edmEntitySet = uriEntityset.getEntitySet();
	// the key for the entity
	List<UriParameter> keyPredicates = uriEntityset.getKeyPredicates();

	// 1.2. retrieve the requested (Edm) property
	// the last segment is the Property
	UriResourceProperty uriProperty = (UriResourceProperty)resourceParts.get(resourceParts.size() -1); 
	EdmProperty edmProperty = uriProperty.getProperty();
	String edmPropertyName = edmProperty.getName();
	// in our example, we know we have only primitive types in our model
	EdmPrimitiveType edmPropertyType = (EdmPrimitiveType) edmProperty.getType();


	// 2. retrieve data from backend
	// 2.1. retrieve the entity data, for which the property has to be read
	Entity entity = storage.readEntityData(edmEntitySet, keyPredicates);
	if (entity == null) { // Bad request
		throw new ODataApplicationException("Entity not found", HttpStatusCode.NOT_FOUND.getStatusCode(), Locale.ENGLISH);
	}

	// 2.2. retrieve the property data from the entity
	Property property = entity.getProperty(edmPropertyName);
	if (property == null) {
		throw new ODataApplicationException("Property not found", HttpStatusCode.NOT_FOUND.getStatusCode(), 
		                                    Locale.ENGLISH);
	}

	// 3. serialize
	Object value = property.getValue();
	if (value != null) {
		// 3.1. configure the serializer
		ODataSerializer serializer = odata.createSerializer(responseFormat);

		ContextURL contextUrl = ContextURL.with().entitySet(edmEntitySet).navOrPropertyPath(edmPropertyName).build();
		PrimitiveSerializerOptions options = PrimitiveSerializerOptions.with().contextURL(contextUrl).build();
		// 3.2. serialize
		SerializerResult serializerResult = serializer.primitive(serviceMetadata, edmPropertyType, property, options);
		InputStream propertyStream = serializerResult.getContent();

		//4. configure the response object
		response.setContent(propertyStream);
		response.setStatusCode(HttpStatusCode.OK.getStatusCode());
		response.setHeader(HttpHeader.CONTENT_TYPE, responseFormat.toContentTypeString());
	} else {
		// in case there's no value for the property, we can skip the serialization
		response.setStatusCode(HttpStatusCode.NO_CONTENT.getStatusCode());
	}
}
 

public void readEntityCollection(ODataRequest request, ODataResponse response,
    UriInfo uriInfo, ContentType responseFormat)
    throws ODataApplicationException, SerializerException {
  
  EdmEntitySet responseEdmEntitySet = null; // we'll need this to build the ContextURL
  EntityCollection responseEntityCollection = null; // we'll need this to set the response body

  // 1st retrieve the requested EntitySet from the uriInfo (representation of the parsed URI)
  List<UriResource> resourceParts = uriInfo.getUriResourceParts();
  int segmentCount = resourceParts.size();

  UriResource uriResource = resourceParts.get(0); // in our example, the first segment is the EntitySet
  if (!(uriResource instanceof UriResourceEntitySet)) {
    throw new ODataApplicationException("Only EntitySet is supported",
        HttpStatusCode.NOT_IMPLEMENTED.getStatusCode(), Locale.ROOT);
  }

  UriResourceEntitySet uriResourceEntitySet = (UriResourceEntitySet) uriResource;
  EdmEntitySet startEdmEntitySet = uriResourceEntitySet.getEntitySet();

  if (segmentCount == 1) { // this is the case for: DemoService/DemoService.svc/Categories
    responseEdmEntitySet = startEdmEntitySet; // the response body is built from the first (and only) entitySet

    // 2nd: fetch the data from backend for this requested EntitySetName and deliver as EntitySet
    responseEntityCollection = storage.readEntitySetData(startEdmEntitySet);
  } else if (segmentCount == 2) { // in case of navigation: DemoService.svc/Categories(3)/Products

    UriResource lastSegment = resourceParts.get(1); // in our example we don't support more complex URIs
    if (lastSegment instanceof UriResourceNavigation) {
      UriResourceNavigation uriResourceNavigation = (UriResourceNavigation) lastSegment;
      EdmNavigationProperty edmNavigationProperty = uriResourceNavigation.getProperty();
      EdmEntityType targetEntityType = edmNavigationProperty.getType();
      // from Categories(1) to Products
      responseEdmEntitySet = Util.getNavigationTargetEntitySet(startEdmEntitySet, edmNavigationProperty);

      // 2nd: fetch the data from backend
      // first fetch the entity where the first segment of the URI points to
      List<UriParameter> keyPredicates = uriResourceEntitySet.getKeyPredicates();
      // e.g. for Categories(3)/Products we have to find the single entity: Category with ID 3
      Entity sourceEntity = storage.readEntityData(startEdmEntitySet, keyPredicates);
      // error handling for e.g. DemoService.svc/Categories(99)/Products
      if (sourceEntity == null) {
        throw new ODataApplicationException("Entity not found.",
            HttpStatusCode.NOT_FOUND.getStatusCode(), Locale.ROOT);
      }
      // then fetch the entity collection where the entity navigates to
      // note: we don't need to check uriResourceNavigation.isCollection(),
      // because we are the EntityCollectionProcessor
      responseEntityCollection = storage.getRelatedEntityCollection(sourceEntity, targetEntityType);
    }
  } else { // this would be the case for e.g. Products(1)/Category/Products
    throw new ODataApplicationException("Not supported",
        HttpStatusCode.NOT_IMPLEMENTED.getStatusCode(), Locale.ROOT);
  }

  // 3rd: create and configure a serializer
  ContextURL contextUrl = ContextURL.with().entitySet(responseEdmEntitySet).build();
  final String id = request.getRawBaseUri() + "/" + responseEdmEntitySet.getName();
  EntityCollectionSerializerOptions opts = EntityCollectionSerializerOptions.with()
      .contextURL(contextUrl).id(id).build();
  EdmEntityType edmEntityType = responseEdmEntitySet.getEntityType();

  ODataSerializer serializer = odata.createSerializer(responseFormat);
  SerializerResult serializerResult = serializer.entityCollection(serviceMetadata, edmEntityType,
      responseEntityCollection, opts);

  // 4th: configure the response object: set the body, headers and status code
  response.setContent(serializerResult.getContent());
  response.setStatusCode(HttpStatusCode.OK.getStatusCode());
  response.setHeader(HttpHeader.CONTENT_TYPE, responseFormat.toContentTypeString());
}
 

@Override
public EntitySet getEntitySet(UriInfo uriInfo) {
	List<UriResource> resourcePaths = uriInfo.getUriResourceParts();

	UriResourceEntitySet uriResourceEntitySet = (UriResourceEntitySet) resourcePaths
			.get(0); // in our example, the first segment is the EntitySet

	EdmEntitySet edmEntitySet = uriResourceEntitySet.getEntitySet();

	EntitySet entitySet = getData(edmEntitySet);

	return entitySet;
}
 

@Override
public EntitySet getEntitySet(UriInfo uriInfo) {
	List<UriResource> resourcePaths = uriInfo.getUriResourceParts();

	UriResourceEntitySet uriResourceEntitySet = (UriResourceEntitySet) resourcePaths
			.get(0); // in our example, the first segment is the EntitySet

	EdmEntitySet edmEntitySet = uriResourceEntitySet.getEntitySet();

	EntitySet entitySet = getData(edmEntitySet);

	return entitySet;
}