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  1. c. Create updateEntity method that gets called on ‘PUT’ method

public void updateEntity(ODataRequest request, ODataResponse response,

                     UriInfo uriInfo, ContentType requestFormat,

                     ContentType responseFormat) throws ODataApplicationException,

                     DeserializerException, SerializerException {

//eg..http://localhost:8088/school_stu_teachers/DemoService.svc/Schools(‘gct‘)

               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);

//get entityset

EdmEntitySet edmEntitySet = uriResourceEntitySet.getEntitySet();

EdmEntityType responseEdmEntityType = edmEntitySet.getEntityType();

if(responseEdmEntityType.getName().equals(DemoEdmProvider.ET_SCHOOL_NAME))

{

                        int school_id;

                        //get school name

                         List<UriParameter> keyPredicates = uriResourceEntitySet.getKeyPredicates();

                         for(UriParameter a:keyPredicates)

                         {

                            System.out.println(a.getText().replaceAll(“‘”,“”));

                         }

              InputStream requestInputStream = request.getBody();

              try {

                     //convert data(from post) to list of maps

                     ObjectMapper mapper = new ObjectMapper();

                     List<Map<String, Object>> jsonmap = mapper.readValue(

                                  requestInputStream,

                                  new TypeReference<List<Map<String, Object>>>() {

                                  });

            

Map<String, Object> b=new HashMap<String, Object>();

for (Map<String, Object> a : jsonmap) {

                           for (String i : a.keySet()) {

                                  System.out.println(“key “ + i + ” value “ + a.get(i));

                           }

                         

                           b.put(“school_id”, a.get(“school_id”));

                           b.put(“schoolName”, a.get(“school_name”));

                           b.put(“studentsDto”, a.get(“studentsDto”));

                                                       String mapAsJson = new ObjectMapper().writeValueAsString(b);

                           //convertjson string to dto

                           //ie..convert json object to java object

                            SchoolDto scho= (SchoolDto) fromJson1(mapAsJson);

                                                       SchoolDto schoolDto=new SchoolDto();

                            SchoolServiceDao dao = new SchoolServiceDao();

                            SchoolDo schoolDo=new SchoolDo();

                            schoolDo=schoolDto.getEntity(scho);

                         

                           try {

                           } catch (Exception e) {

                                  System.out.println(“Exception:”+e.getMessage());

                           }

                           //get school entity

                           Entity school_entity = storage.readEntityData(edmEntitySet, keyPredicates);

                           school_id=(int)school_entity.getProperty(“school_id”).getValue();

                           //update schoolDo with input Do by matching id

                     dao.update1(schoolDo,school_id);

                     }

              } catch (Exception e1) {

                     System.out.println(“Exception1:”+e1.getMessage());

              }}

               }

  1. d. deleteEntity method that gets called on ‘DELETE’ request

       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();

       EdmEntityType responseEdmEntityType = edmEntitySet.getEntityType();

          if(responseEdmEntityType.getName().equals(DemoEdmProvider.ET_SCHOOL_NAME))

{

String school_name=“”;

List<UriParameter> keyPredicates = uriResourceEntitySet.getKeyPredicates();

for(UriParameter a:keyPredicates)

{

//eg. http://localhost:8088/school_stu_teachers/DemoService.svc/Schools(‘psg‘)

//here,’psg‘ is keypredicate

System.out.println(school_name=a.getText().replaceAll(“‘”,“”));

}

// storage.deleteEntityData(edmEntitySet, keyPredicates);

SchoolServiceDao dao = new SchoolServiceDao();

//delete entry from db

                     dao.delete(school_name);

response.setStatusCode(HttpStatusCode.OK.getStatusCode());

                              }

          else

if(responseEdmEntityType.getName().equals(DemoEdmProvider.ET_STUDENT_NAME))

{

       String student_id=“”;

                         // 2. delete the data in backend

List<UriParameter> keyPredicates = uriResourceEntitySet.getKeyPredicates();

                         for(UriParameter a:keyPredicates)

                         {

                            //String name=a.getName();

                            System.out.println(student_id=a.getText());

                         }

                       // storage.deleteEntityData(edmEntitySet, keyPredicates);

                        SchoolServiceDao dao = new SchoolServiceDao();

                           dao.delete1(Integer.parseInt(student_id));

                         //dao.delete(4);

                         //3. configure the response object

                         response.setStatusCode(HttpStatusCode.OK.getStatusCode());

                                     }

                   

            

       }

3)Create processor (for Entity Collection) that implements EntityCollectionprocessor:

  1. a. Create readEntityCollection method that gets called on ‘GET’ request

/*

   * This method is invoked when a collection of entities has to be read.

   * In our example, this can be either a “normal” read operation, or a navigation:

   *

   * Example for “normal” read entity set operation:

   * http://localhost:8080/DemoService/DemoService.svc/Categories

   *

   * Example for navigation

   * http://localhost:8080/DemoService/DemoService.svc/Categories(3)/Products

   */

  public void readEntityCollection(ODataRequest request, ODataResponse response,

      UriInfo uriInfo, ContentType responseFormat)

      throws ODataApplicationException, SerializerException {

SerializerResult serializerResult=null;

List<UriResource> resourceParts = uriInfo.getUriResourceParts();

              int segmentCount = resourceParts.size();

              System.out.println(“segment count”+segmentCount);

// 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.readEntitySetDataFromDatabase(edmEntitySet);

List<UriParameter> keyPredicates = uriResourceEntitySet

                           .getKeyPredicates();

       

System.out.println(“segment c”);

if(segmentCount==1){

//eg..http://localhost:8088/school_stu_teachers/DemoService.svc/Schools

         //  EntityCollection entityCollection = storage.readEntitySetData(edmEntitySet);

EntityCollection modifiedEntityCollection = new EntityCollection();

List<Entity> modifiedEntityList = new ArrayList<Entity>();

modifiedEntityList.addAll(entityCollection.getEntities());

                   

                     // 3rd: Apply system query option

              // The system query options have to be applied in a defined order

                     // 3.1.) $filter

       

modifiedEntityList = applyExpandQueryOption(modifiedEntityList, edmEntitySet, uriInfo.getExpandOption());

// 3.8.) $select

SelectOption selectOption = uriInfo.getSelectOption();

// Set the (may) modified entityList to the new entity collection

modifiedEntityCollection.getEntities().addAll(modifiedEntityList);

// 4th: create a serializer based on the requested format (json)

ODataSerializer serializer = odata.createSerializer(responseFormat);

                   

// we need the property names of the $select, in order to build the context URL

                     EdmEntityType edmEntityType = edmEntitySet.getEntityType();

String selectList = odata.createUriHelper()

.buildContextURLSelectList(edmEntityType, uriInfo.getExpandOption(), selectOption);

ContextURL contextUrl = ContextURL.with().entitySet(edmEntitySet).selectList(selectList).build();

// adding the selectOption to the serializerOpts will actually tell the lib to do the job

final String id = request.getRawBaseUri() + “/” + edmEntitySet.getName();

EntityCollectionSerializerOptions opts = EntityCollectionSerializerOptions.with()

.contextURL(contextUrl)

.count(uriInfo.getCountOption())

.select(selectOption)

.expand(uriInfo.getExpandOption())

                                                                                     .id(id)

.build();

serializerResult = serializer.entityCollection(srvMetadata, edmEntityType,

entityCollection, opts);

  }

if(segmentCount==2){

//eg..http://localhost:8088/school_stu_teachers/DemoService.svc/Schools(‘psg’)/Students

//in this case get(1) represents schools entity set

                        UriResource navSegment = resourceParts.get(1);

                        UriResourceNavigation uriResourceNavigation = (UriResourceNavigation) navSegment;

                           EdmNavigationProperty edmNavigationProperty = uriResourceNavigation

                                         .getProperty();

                           EdmEntityType targetEntityType = edmNavigationProperty.getType();

                           // contextURL displays the last segment

                           //System.out.println(” “+startEdmEntitySet.getEntityType());

                           EdmEntitySet TargetEntitySet = Util.getNavigationTargetEntitySet(

                                         edmEntitySet, edmNavigationProperty);

//in this case keypredicates is ‘psg

if(keyPredicates.size()!=0 && keyPredicates!=null)

{

//get school that has name ‘psg‘…ie) get school entity

Entity entity = storage.readEntityDataFromDatabase(edmEntitySet,keyPredicates);

                      

                        //here, get students for the related school ie) students of school psg

entityCollection=storage.getRelatedEntityCollection(entity, targetEntityType);

}

ODataSerializer serializer = odata.createSerializer(responseFormat);

ContextURL contextUrl = ContextURL.with().entitySet(TargetEntitySet).build();

final String id = request.getRawBaseUri() + “/” + TargetEntitySet.getName();

EntityCollectionSerializerOptions opts = EntityCollectionSerializerOptions.with()

                    .contextURL(contextUrl)

                    .count(uriInfo.getCountOption())

                    .id(id)

                    .build();

serializerResult = serializer.entityCollection(srvMetadata, targetEntityType,

entityCollection, opts);   

}

// and serialize the content: transform from the EntitySet object to InputStream

        

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());

         }

  1. b. Method for ‘expand’ query option

  private List<Entity> applyExpandQueryOption(List<Entity> modifiedEntityList,

EdmEntitySet edmEntitySet, ExpandOption expandOption) {

// in our example: http://localhost:8088/school_stu_teachers/DemoService.svc/Schools?$expand=Students

// or http://localhost:8088/school_stu_teachers/DemoService.svc/Students?$expand=School

if (expandOption != null) {

//since we have more than 1 navigation property ie..students and teachers,we use loop

//http://localhost:8088/school_stu_teachers/DemoService.svc/Schools?$expand=Students,Teachers

              for(int i=0;i<expandOption.getExpandItems().size();i++){

// retrieve the EdmNavigationProperty from the expand expression

EdmNavigationProperty edmNavigationProperty = null;

ExpandItem expandItem = expandOption.getExpandItems().get(i);

if (expandItem.isStar()) {

List<EdmNavigationPropertyBinding> bindings = edmEntitySet.getNavigationPropertyBindings();

// we know that there are navigation bindings

// however normally in this case  check if navigation bindings exists

if (!bindings.isEmpty()) {

//since we have more than 1 navigation binding ie. for teachers,for students

EdmNavigationPropertyBinding binding = bindings.get(i);

EdmElement property = edmEntitySet.getEntityType().getProperty(binding.getPath());

// we don’t need to handle error cases, as it is done in the Olingo library

if (property instanceof EdmNavigationProperty) {

                   edmNavigationProperty = (EdmNavigationProperty) property;

}

}

} else {

// can be ‘School’ or ‘Students’, no path supported

UriResource uriResource = expandItem.getResourcePath().getUriResourceParts().get(0);

// we don’t need to handle error cases, as it is done in the Olingo library

if (uriResource instanceof UriResourceNavigation) {

edmNavigationProperty = ((UriResourceNavigation) uriResource).getProperty();

}

}

          // can be ‘School’ or ‘Students’, no path supported

// we don’t need to handle error cases, as it is done in the Olingo library

if (edmNavigationProperty != null) {

String navPropName = edmNavigationProperty.getName();

EdmEntityType expandEdmEntityType = edmNavigationProperty.getType();

for (Entity entity : modifiedEntityList) {

Link link = new Link();

link.setTitle(navPropName);

link.setType(Constants.ENTITY_NAVIGATION_LINK_TYPE);

link.setRel(Constants.NS_ASSOCIATION_LINK_REL + navPropName);

if (edmNavigationProperty.isCollection()) { // in case of Schools/$expand=Students

                   // fetch the data for the $expand (to-many navigation) from backend

EntityCollection expandEntityCollection = storage.getRelatedEntityCollection(entity, expandEdmEntityType);

                   link.setInlineEntitySet(expandEntityCollection);

                   link.setHref(expandEntityCollection.getId().toASCIIString());

} else { // in case of Students?$expand=School

// fetch the data for the $expand (to-one navigation) from backend

                   // here we get the data for the expand

                   Entity expandEntity = storage.getRelatedEntity(entity, expandEdmEntityType);

                   link.setInlineEntity(expandEntity);

                   link.setHref(expandEntity.getId().toASCIIString());

}

// set the link – containing the expanded data – to the current entity

entity.getNavigationLinks().add(link);

}

}

}

}

return modifiedEntityList;

         }

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