Java Code Examples for org.apache.olingo.commons.api.edm.EdmProperty#getType()

@Test
public void getTypeReturnsTypeDefinition() throws Exception {
  CsdlEdmProvider provider = mock(CsdlEdmProvider.class);
  EdmProviderImpl edm = new EdmProviderImpl(provider);
  final FullQualifiedName typeName = new FullQualifiedName("ns", "definition");
  CsdlTypeDefinition typeProvider =
      new CsdlTypeDefinition().setUnderlyingType(new FullQualifiedName("Edm", "String"));
  when(provider.getTypeDefinition(typeName)).thenReturn(typeProvider);
  CsdlProperty propertyProvider = new CsdlProperty();
  propertyProvider.setType(typeName);
  final EdmProperty property = new EdmPropertyImpl(edm, propertyProvider);
  assertFalse(property.isPrimitive());
  final EdmType type = property.getType();
  assertEquals(EdmTypeKind.DEFINITION, type.getKind());
  assertEquals("ns", type.getNamespace());
  assertEquals("definition", type.getName());
}
 

@Override
public VisitorOperand visitMember(Member member) throws ExpressionVisitException, ODataApplicationException {
    final List<UriResource> uriResourceParts = member.getResourcePath().getUriResourceParts();
    int size = uriResourceParts.size();
    if (uriResourceParts.get(0) instanceof UriResourceProperty) {
        EdmProperty currentEdmProperty = ((UriResourceProperty) uriResourceParts.get(0)).getProperty();
        Property currentProperty = entity.getProperty(currentEdmProperty.getName());
        return new TypedOperand(currentProperty.getValue(), currentEdmProperty.getType(), currentEdmProperty);
    } else if (uriResourceParts.get(size - 1) instanceof UriResourceLambdaAll) {
        return throwNotImplemented();
    } else if (uriResourceParts.get(size - 1) instanceof UriResourceLambdaAny) {
        return throwNotImplemented();
    } else {
        return throwNotImplemented();
    }
}
 

private Property createProperty(final EdmProperty edmProperty, final String propertyName)
    throws DataProviderException {
  final EdmType type = edmProperty.getType();
  Property newProperty;
  if (edmProperty.isPrimitive()
      || type.getKind() == EdmTypeKind.ENUM || type.getKind() == EdmTypeKind.DEFINITION) {
    newProperty = edmProperty.isCollection() ?
        DataCreator.createPrimitiveCollection(propertyName) :
        DataCreator.createPrimitive(propertyName, null);
  } else {
    if (edmProperty.isCollection()) {
      @SuppressWarnings("unchecked")
      Property newProperty2 = DataCreator.createComplexCollection(propertyName, 
          edmProperty.getType().getFullQualifiedName().getFullQualifiedNameAsString());
      newProperty = newProperty2;
    } else {
      newProperty = DataCreator.createComplex(propertyName,
          edmProperty.getType().getFullQualifiedName().getFullQualifiedNameAsString());
      createProperties((EdmComplexType) type, newProperty.asComplex().getValue());
    }
  }
  return newProperty;
}
 

@Override
public String buildKeyPredicate(final EdmEntityType edmEntityType, final Entity entity) throws SerializerException {
  StringBuilder result = new StringBuilder();
  final List<String> keyNames = edmEntityType.getKeyPredicateNames();
  boolean first = true;
  for (final String keyName : keyNames) {
    EdmKeyPropertyRef refType = edmEntityType.getKeyPropertyRef(keyName);
    if (first) {
      first = false;
    } else {
      result.append(',');
    }
    if (keyNames.size() > 1) {
      result.append(Encoder.encode(keyName)).append('=');
    }
    final EdmProperty edmProperty =  refType.getProperty();
    if (edmProperty == null) {
      throw new SerializerException("Property not found (possibly an alias): " + keyName,
          SerializerException.MessageKeys.MISSING_PROPERTY, keyName);
    }
    final EdmPrimitiveType type = (EdmPrimitiveType) edmProperty.getType();
    final Object propertyValue = findPropertyRefValue(entity, refType);
    try {
      final String value = type.toUriLiteral(
          type.valueToString(propertyValue,
              edmProperty.isNullable(), edmProperty.getMaxLength(),
              edmProperty.getPrecision(), edmProperty.getScale(), edmProperty.isUnicode()));
      result.append(Encoder.encode(value));
    } catch (final EdmPrimitiveTypeException e) {
      throw new SerializerException("Wrong key value!", e,
          SerializerException.MessageKeys.WRONG_PROPERTY_VALUE, edmProperty.getName(), 
          propertyValue != null ? propertyValue.toString(): null);
    }
  }
  return result.toString();
}
 

private void writePropertyType(final EdmProperty edmProperty, JsonGenerator json)
    throws SerializerException, IOException {
  if (!isODataMetadataFull) {
    return;
  }
  String typeName = edmProperty.getName() + constants.getType();
  final EdmType type = edmProperty.getType();
  if (type.getKind() == EdmTypeKind.ENUM || type.getKind() == EdmTypeKind.DEFINITION) {
    if (edmProperty.isCollection()) {
      json.writeStringField(typeName, 
          "#Collection(" + type.getFullQualifiedName().getFullQualifiedNameAsString() + ")");
    } else {
      json.writeStringField(typeName, "#" + type.getFullQualifiedName().getFullQualifiedNameAsString());
    }
  } else if (edmProperty.isPrimitive()) {
    if (edmProperty.isCollection()) {
      json.writeStringField(typeName, "#Collection(" + type.getFullQualifiedName().getName() + ")");
    } else {
      // exclude the properties that can be heuristically determined
      if (type != EdmPrimitiveTypeFactory.getInstance(EdmPrimitiveTypeKind.Boolean) &&
          type != EdmPrimitiveTypeFactory.getInstance(EdmPrimitiveTypeKind.Double) &&
          type != EdmPrimitiveTypeFactory.getInstance(EdmPrimitiveTypeKind.String)) {
        json.writeStringField(typeName, "#" + type.getFullQualifiedName().getName());                  
      }
    }
  } else if (type.getKind() == EdmTypeKind.COMPLEX) {
    // non-collection case written in writeComplex method directly.
    if (edmProperty.isCollection()) {
      json.writeStringField(typeName, 
          "#Collection(" + type.getFullQualifiedName().getFullQualifiedNameAsString() + ")");
    }
  } else {
    throw new SerializerException("Property type not yet supported!",
        SerializerException.MessageKeys.UNSUPPORTED_PROPERTY_TYPE, edmProperty.getName());
  }    
}
 

public Entity readDataFromEntity(final EdmEntityType edmEntityType,
    final List<UriParameter> keys) throws DataProviderException {
  EntityCollection coll = data.get(edmEntityType.getName());
  List<Entity> entities = coll.getEntities();
  try {
    for (final Entity entity : entities) {
      boolean found = true;
      for (final UriParameter key : keys) {
        EdmKeyPropertyRef refType = edmEntityType.getKeyPropertyRef(key.getName());
        Object value =  findPropertyRefValue(entity, refType);
        
        final EdmProperty property = refType.getProperty();
        final EdmPrimitiveType type = (EdmPrimitiveType) property.getType();
        
        if (key.getExpression() != null && !(key.getExpression() instanceof Literal)) {
          throw new DataProviderException("Expression in key value is not supported yet!",
              HttpStatusCode.NOT_IMPLEMENTED);
        }
        final String text = key.getAlias() == null ? key.getText() : ((Literal) key.getExpression()).getText();
        Object keyValue = null;
        if (Calendar.class.isAssignableFrom(value.getClass())) {
          keyValue = type.valueOfString(type.fromUriLiteral(text),
              property.isNullable(), property.getMaxLength(), property.getPrecision(), property.getScale(),
              property.isUnicode(), Calendar.class);
        } else {
          keyValue = type.valueOfString(type.fromUriLiteral(text),
              property.isNullable(), property.getMaxLength(), property.getPrecision(), property.getScale(),
              property.isUnicode(), value.getClass());
        }
        if (!value.equals(keyValue)) {
          found = false;
          break;
        }
      }
      if (found) {
        return entity;
      }
    }
    return null;
  } catch (final EdmPrimitiveTypeException e) {
    throw new DataProviderException("Wrong key!", HttpStatusCode.BAD_REQUEST, e);
  }
}
 

public static boolean entityMatchesAllKeys(EdmEntityType edmEntityType, Entity entity, List<UriParameter> keyParams)
        throws ODataApplicationException {

  // loop over all keys
  for (final UriParameter key : keyParams) {
    // key
    String keyName = key.getName();
    String keyText = key.getText();
    
    // Edm: we need this info for the comparison below
    EdmProperty edmKeyProperty = (EdmProperty) edmEntityType.getProperty(keyName);
    Boolean isNullable = edmKeyProperty.isNullable();
    Integer maxLength = edmKeyProperty.getMaxLength();
    Integer precision = edmKeyProperty.getPrecision();
    Boolean isUnicode = edmKeyProperty.isUnicode();
    Integer scale = edmKeyProperty.getScale();
    // get the EdmType in order to compare
    EdmType edmType = edmKeyProperty.getType();
    EdmPrimitiveType edmPrimitiveType = (EdmPrimitiveType) edmType;

    // Runtime data: the value of the current entity
    // don't need to check for null, this is done in olingo library
    Object valueObject = entity.getProperty(keyName).getValue();

    // now need to compare the valueObject with the keyText String
    // this is done using the type.valueToString //
    String valueAsString = null;
    try {
      valueAsString = edmPrimitiveType.valueToString(valueObject, isNullable, maxLength, precision, scale, isUnicode);
    } catch (EdmPrimitiveTypeException e) {
      throw new ODataApplicationException("Failed to retrieve String value", HttpStatusCode.INTERNAL_SERVER_ERROR
          .getStatusCode(), Locale.ENGLISH, e);
    }

    if (valueAsString == null) {
      return false;
    }

    boolean matches = valueAsString.equals(keyText);
    if (!matches) {
      // if any of the key properties is not found in the entity, we don't need to search further
      return false;
    }
  }

  return true;
}
 

private boolean isStreamProperty(EdmProperty edmProperty) {
  final EdmType type = edmProperty.getType();
  return (edmProperty.isPrimitive() && type == EdmPrimitiveTypeFactory.getInstance(EdmPrimitiveTypeKind.Stream));    
}
 

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 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.ROOT);
	}

	// 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.ROOT);
	}

	// 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 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 static boolean entityMatchesAllKeys(EdmEntityType edmEntityType, Entity entity, List<UriParameter> keyParams)
        throws ODataApplicationException {

  // loop over all keys
  for (final UriParameter key : keyParams) {
    // key
    String keyName = key.getName();
    String keyText = key.getText();

    // Edm: we need this info for the comparison below
    EdmProperty edmKeyProperty = (EdmProperty) edmEntityType.getProperty(keyName);
    Boolean isNullable = edmKeyProperty.isNullable();
    Integer maxLength = edmKeyProperty.getMaxLength();
    Integer precision = edmKeyProperty.getPrecision();
    Boolean isUnicode = edmKeyProperty.isUnicode();
    Integer scale = edmKeyProperty.getScale();
    // get the EdmType in order to compare
    EdmType edmType = edmKeyProperty.getType();
    EdmPrimitiveType edmPrimitiveType = (EdmPrimitiveType) edmType;

    // Runtime data: the value of the current entity
    // don't need to check for null, this is done in olingo library
    Object valueObject = entity.getProperty(keyName).getValue();

    // now need to compare the valueObject with the keyText String
    // this is done using the type.valueToString
    String valueAsString;
    try {
      valueAsString = edmPrimitiveType.valueToString(valueObject, isNullable, maxLength, precision, scale, isUnicode);
    } catch (EdmPrimitiveTypeException e) {
      throw new ODataApplicationException("Failed to retrieve String value", HttpStatusCode.INTERNAL_SERVER_ERROR
              .getStatusCode(), Locale.ENGLISH, e);
    }

    if (valueAsString == null) {
      return false;
    }

    boolean matches = valueAsString.equals(keyText);
    if (!matches) {
      // if any of the key properties is not found in the entity, we don't need to search further
      return false;
    }
  }

  return true;
}
 

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());
	}
}
 

protected static UriInfoImpl parseExpandPath(UriTokenizer tokenizer, final Edm edm,
    final EdmStructuredType referencedType, ExpandItemImpl item) throws UriParserException {
  UriInfoImpl resource = new UriInfoImpl().setKind(UriInfoKind.resource);

  EdmStructuredType type = referencedType;
  String name = null;
  while (tokenizer.next(TokenKind.ODataIdentifier)) {
    name = tokenizer.getText();
    final EdmProperty property = type.getStructuralProperty(name);
    if (property != null && property.getType().getKind() == EdmTypeKind.COMPLEX) {
      type = (EdmStructuredType) property.getType();
      UriResourceComplexPropertyImpl complexResource = new UriResourceComplexPropertyImpl(property);
      ParserHelper.requireNext(tokenizer, TokenKind.SLASH);
      final EdmStructuredType typeCast = ParserHelper.parseTypeCast(tokenizer, edm, type);
      if (typeCast != null) {
        complexResource.setTypeFilter(typeCast);
        ParserHelper.requireNext(tokenizer, TokenKind.SLASH);
        type = typeCast;
      }
      resource.addResourcePart(complexResource);
    }
  }

  final EdmNavigationProperty navigationProperty = type.getNavigationProperty(name);
  if (navigationProperty == null) {
    //For handling $expand with Stream Properties in version 4.01
    final EdmProperty streamProperty = (EdmProperty) type.getProperty(name);
    if(streamProperty != null && streamProperty.getType() ==  EdmPrimitiveTypeFactory.
        getInstance(EdmPrimitiveTypeKind.Stream)){
      resource.addResourcePart(new UriResourcePrimitivePropertyImpl(streamProperty));
    }else if (tokenizer.next(TokenKind.STAR)) {
      item.setIsStar(true);
    } else {
      throw new UriParserSemanticException(
          "Navigation Property '" + name + "' not found in type '" + type.getFullQualifiedName() + "'.",
          UriParserSemanticException.MessageKeys.EXPRESSION_PROPERTY_NOT_IN_TYPE, type.getName(), name);
    }
  } else {
    resource.addResourcePart(new UriResourceNavigationPropertyImpl(navigationProperty));
  }

  return resource;
}
 

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 static boolean entityMatchesAllKeys(EdmEntityType edmEntityType, Entity rt_entity,
    List<UriParameter> keyParams) {

  // loop over all keys
  for (final UriParameter key : keyParams) {
    // key
    String keyName = key.getName();
    String keyText = key.getText();

    // note: below line doesn't consider: keyProp can be part of a complexType in V4
    // in such case, it would be required to access it via getKeyPropertyRef()
    // but since this isn't the case in our model, we ignore it in our implementation
    EdmProperty edmKeyProperty = (EdmProperty) edmEntityType.getProperty(keyName);
    // Edm: we need this info for the comparison below
    Boolean isNullable = edmKeyProperty.isNullable();
    Integer maxLength = edmKeyProperty.getMaxLength();
    Integer precision = edmKeyProperty.getPrecision();
    Boolean isUnicode = edmKeyProperty.isUnicode();
    Integer scale = edmKeyProperty.getScale();
    // get the EdmType in order to compare
    EdmType edmType = edmKeyProperty.getType();
    // if(EdmType instanceof EdmPrimitiveType) // do we need this?
    EdmPrimitiveType edmPrimitiveType = (EdmPrimitiveType) edmType;

    // Runtime data: the value of the current entity
    // don't need to check for null, this is done in FWK
    Object valueObject = rt_entity.getProperty(keyName).getValue();
    // TODO if the property is a complex type

    // now need to compare the valueObject with the keyText String
    // this is done using the type.valueToString
    String valueAsString = null;
    try {
      valueAsString = edmPrimitiveType.valueToString(valueObject, isNullable,
          maxLength, precision, scale, isUnicode);
    } catch (EdmPrimitiveTypeException e) {
      return false; // TODO proper Exception handling
    }

    if (valueAsString == null) {
      return false;
    }

    boolean matches = valueAsString.equals(keyText);
    // if any of the key properties is not found in the entity, we don't need to search further
    if (!matches) {
      return false;
    }
    // if the given key value is found in the current entity, continue with the next key
  }

  return true;
}
 

public Entity read(final EdmEntityType edmEntityType, final EntityCollection entitySet,
    final List<UriParameter> keys) throws DataProviderException {
  try {
    for (final Entity entity : entitySet.getEntities()) {
      boolean found = true;
      for (final UriParameter key : keys) {
        EdmKeyPropertyRef refType = edmEntityType.getKeyPropertyRef(key.getName());
        Object value =  findPropertyRefValue(entity, refType);
        
        final EdmProperty property = refType.getProperty();
        final EdmPrimitiveType type = (EdmPrimitiveType) property.getType();
        
        if (key.getExpression() != null && !(key.getExpression() instanceof Literal)) {
          throw new DataProviderException("Expression in key value is not supported yet!",
              HttpStatusCode.NOT_IMPLEMENTED);
        }
        Object keyValue = null;
        final String text = key.getAlias() == null ? key.getText() : ((Literal) key.getExpression()).getText();
        if (Calendar.class.isAssignableFrom(value.getClass())) {
          keyValue = type.valueOfString(type.fromUriLiteral(text),
              property.isNullable(), property.getMaxLength(), property.getPrecision(), property.getScale(),
              property.isUnicode(), Calendar.class);
        } else {
          keyValue = type.valueOfString(type.fromUriLiteral(text),
              property.isNullable(), property.getMaxLength(), property.getPrecision(), property.getScale(),
              property.isUnicode(), value.getClass());
        }
        if (!value.equals(keyValue)) {
          found = false;
          break;
        }
      }
      if (found) {
        return entity;
      }
    }
    return null;
  } catch (final EdmPrimitiveTypeException e) {
    throw new DataProviderException("Wrong key!", HttpStatusCode.BAD_REQUEST, e);
  }
}
 

public static boolean entityMatchesAllKeys(EdmEntityType edmEntityType, Entity entity, List<UriParameter> keyParams)
        throws ODataApplicationException {

  // loop over all keys
  for (final UriParameter key : keyParams) {
    // key
    String keyName = key.getName();
    String keyText = key.getText();

    // Edm: we need this info for the comparison below
    EdmProperty edmKeyProperty = (EdmProperty) edmEntityType.getProperty(keyName);
    Boolean isNullable = edmKeyProperty.isNullable();
    Integer maxLength = edmKeyProperty.getMaxLength();
    Integer precision = edmKeyProperty.getPrecision();
    Boolean isUnicode = edmKeyProperty.isUnicode();
    Integer scale = edmKeyProperty.getScale();
    // get the EdmType in order to compare
    EdmType edmType = edmKeyProperty.getType();
    EdmPrimitiveType edmPrimitiveType = (EdmPrimitiveType) edmType;

    // Runtime data: the value of the current entity
    // don't need to check for null, this is done in olingo library
    Object valueObject = entity.getProperty(keyName).getValue();

    // now need to compare the valueObject with the keyText String
    // this is done using the type.valueToString
    String valueAsString;
    try {
      valueAsString = edmPrimitiveType.valueToString(valueObject, isNullable, maxLength, precision, scale, isUnicode);
    } catch (EdmPrimitiveTypeException e) {
      throw new ODataApplicationException("Failed to retrieve String value", HttpStatusCode.INTERNAL_SERVER_ERROR
              .getStatusCode(), Locale.ENGLISH, e);
    }

    if (valueAsString == null) {
      return false;
    }

    boolean matches = valueAsString.equals(keyText);
    if (!matches) {
      // if any of the key properties is not found in the entity, we don't need to search further
      return false;
    }
  }

  return true;
}
 

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 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 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());
	}
}