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How to use HATEOAS with a custom page

I'm using spring boot to create a web service.
I'm trying to introduce HATEOAS to an endpoint. Here's the model(DTO):
public class MovieResponse {
private Long id;
private String name;
private Date releaseDate;
private Time runtime;
private Float rating;
private String storyline;
private String poster;
private String rated;
private Date createdAt;
private List<GenreResponse> genres = new ArrayList<>();
private List<MovieMediaResponse> videos = new ArrayList<>();
private List<MovieMediaResponse> photos = new ArrayList<>();
private List<MovieReviewResponse> reviews = new ArrayList<>();
private List<MovieCelebrityResponse> cast = new ArrayList<>();
private List<MovieCelebrityResponse> writers = new ArrayList<>();
private List<MovieCelebrityResponse> directors = new ArrayList<>();
// Getters & Setters
}
Also i have a PagedResponse which holds the page information:
public class PagedResponse<T> {
private List<T> content;
private int page;
private int size;
private long totalElements;
private int totalPages;
private boolean last;
public PagedResponse() {}
public PagedResponse(List<T> content, int page, int size, long totalElements, int totalPages, boolean last) {
this.content = content;
this.page = page;
this.size = size;
this.totalElements = totalElements;
this.totalPages = totalPages;
this.last = last;
}
// Getters & Setters
}
I also have getAllMovies method in the service which return PagedResponse<MovieResponse>.
Now here's MovieResourceAssembler
#Component
public class MovieResourceAssembler implements ResourceAssembler<MovieResponse, Resource<MovieResponse>> {
private EntityLinks entityLinks;
#Autowired
public void setEntityLinks(EntityLinks entityLinks) {
this.entityLinks = entityLinks;
}
#Override
public Resource<MovieResponse> toResource(MovieResponse movieResponse) {
Link self = entityLinks.linkFor(MovieResponse.class).slash(movieResponse.getId()).withSelfRel();
Link rel = entityLinks.linkFor(MovieResponse.class).slash(movieResponse.getId()).withRel("movie");
Link movieGenres = entityLinks.linkFor(MovieResponse.class).slash(movieResponse.getId()).slash("movieGenres").withRel("movieGenres");
Link movieReviews = entityLinks.linkFor(MovieResponse.class).slash(movieResponse.getId()).slash("movieReviews").withRel("movieReviews");
return new Resource<>(movieResponse, self, rel, movieGenres, movieReviewsa);
}
}
When i try to use it in my controller like the following :
#RestController
public class MovieController {
private MovieService movieService;
private PagedResourcesAssembler<MovieResponse> pagedAssembler;
private MovieResourceAssembler movieResourceAssembler;
#Autowired
public MovieController(MovieService movieService, PagedResourcesAssembler<MovieResponse> pagedAssembler, MovieResourceAssembler movieResourceAssembler) {
this.movieService = movieService;
this.pagedAssembler = pagedAssembler;
this.movieResourceAssembler = movieResourceAssembler;
}
#GetMapping("/movies")
public ResponseEntity<?> getAllMovies(#RequestParam(value = "page", defaultValue = DEFAULT_PAGE_NUMBER) String page,
#RequestParam(value = "size", defaultValue = DEFAULT_PAGE_SIZE) String size,
#RequestParam(value = "sort", defaultValue = "createdAt") String sort,
#RequestParam(value = "direction", defaultValue = "desc") String direction) {
PagedResponse<MovieResponse> response = this.movieService.getAllMovies(page, size, sort, direction);
return ResponseEntity.ok(this.pagedAssembler.toResource(response, this.movieResourceAssembler));
}
}
got the following Error:
Cannot resolve method 'toResource(com.movies.mmdb.util.PagedResponse, com.movies.mmdb.controller.MovieResourceAssembler)'
in this line: return ResponseEntity.ok(this.pagedAssembler.toResource(response, this.movieResourceAssembler));
i think toResource accept org.springframework.data.domain.Page; while i'm passing response variable which is PagedResponse.
How can i fix that ?

If toResource method receives a Page<T> as the first parameter, then why don't you use that data type? If you need to extend Page then your class should implement such interface to fulfill the method signature:
public class PagedResponse<T> implements Page<MovieResponse>

Ljava.lang.Object; cannot be cast to model

in this case, i want to show Json to an response page in java hibernate, query method from DAO like this:
public List<TransactionQR> getAllTransaction() throws HibernateException {
return this.session.createQuery("FROM TransactionQR tr, Batch b, Terminal t, User_Smartphone us, Merchant mc WHERE tr.batch = b.id AND b.user_smartphone = us.id AND b.terminal = t.id AND t.merchant = mc.id AND state = '1' ").list();
}
then in servlet class i try to convert the list into json using Json object and json array then write in response like this:
int start = 0;
String jsonResult = null;
JSONObject jo=new JSONObject();
HttpServletRequest request = context.getRequest();
HttpServletResponse response = context.getResponse();
HttpSession session = context.getSession();
DB db = getDB(context);
//JSONObject jo = new JSONObject();
QRTransactionDao QR = new QRTransactionDao(db);
//Gson objGson = new GsonBuilder().setPrettyPrinting().create();
//String json = objGson.toJson(QR.getAllTransaction());
//System.out.println(json);
List<TransactionQR> str = QR.getAllTransaction();
JSONArray array = new JSONArray();
for(TransactionQR tr : str){
JSONObject str3 = new JSONObject();
str3.put("amount", tr.getAmount());
context.put("jsoncontent", jsonResult);
array.add(str3);
}
jo.put("status", "ok");
jo.put("dataqr", array);
jsonResult=jo.toString();
response.setContentType("application/json");
response.getWriter().print(jsonResult);
but i got the error on syntax in this line loop:
for(TransactionQR tr : str){
the error like this:
[Ljava.lang.Object; cannot be cast to Transaction
here the model Transaction:
package id.co.keriss.consolidate.ee;
import java.io.Serializable;
import java.util.Date;
public class TransactionQR implements Serializable{
private Long id;
private String codeqr;
private Date approvaltime;
private String merchant;
private String code_merchant;
private Long amount;
private Long saldoawal;
private Integer tracenumber;
private String state;
private Date createdate;
private Batch batch;
public TransactionQR() {
}
public TransactionQR(Long id, String codeqr, Date approvaltime, String merchant, String code_merchant, Long amount,
Long saldoawal, Integer tracenumber, String state, Date createdate, Batch batch) {
super();
this.id = id;
this.codeqr = codeqr;
this.approvaltime = approvaltime;
this.merchant = merchant;
this.code_merchant = code_merchant;
this.amount = amount;
this.saldoawal = saldoawal;
this.tracenumber = tracenumber;
this.state = state;
this.createdate = createdate;
this.batch = batch;
}
public Long getId() {
return id;
}
public Date getApprovalTime() {
return approvaltime;
}
public Batch getBatch() {
return batch;
}
public void setBatch(Batch batch) {
this.batch = batch;
}
public void setApprovalTime(Date approvalTime) {
this.approvaltime = approvalTime;
}
public void setId(Long id) {
this.id = id;
}
public Date getApprovaltime() {
return approvaltime;
}
public void setApprovaltime(Date approvaltime) {
this.approvaltime = approvaltime;
}
public String getCodeqr() {
return codeqr;
}
public void setCodeqr(String codeqr) {
this.codeqr = codeqr;
}
public String getMerchant() {
return merchant;
}
public void setMerchant(String merchant) {
this.merchant = merchant;
}
public String getCode_merchant() {
return code_merchant;
}
public void setCode_merchant(String code_merchant) {
this.code_merchant = code_merchant;
}
public Long getAmount() {
return amount;
}
public void setAmount(Long amount) {
this.amount = amount;
}
public Long getSaldoawal() {
return saldoawal;
}
public void setSaldoawal(Long saldoawal) {
this.saldoawal = saldoawal;
}
public Integer getTracenumber() {
return tracenumber;
}
public void setTracenumber(Integer tracenumber) {
this.tracenumber = tracenumber;
}
public String getState() {
return state;
}
public void setState(String state) {
this.state = state;
}
public Date getCreatedate() {
return createdate;
}
public void setCreatedate(Date createdate) {
this.createdate = createdate;
}
}
i have try to handle the list with Gson:
Gson objGson = new GsonBuilder().setPrettyPrinting().create();
String json = objGson.toJson(QR.getAllTransaction());
System.out.println(json);
in that way, it's work to show but it's not from POJO right i want work with pojo to parse the data to json ?
why i get the error can't cast to model ? any clue ?

Try adding Select tr to your query in getAllTransaction()

Wich is the relation between QRTransactionDao and TransactionQR ?

Room TypeConverter not working

I have an issue with Room not recognizing my converter. Error:
Cannot figure out how to save this field into database. You can consider adding a type converter for it.
I need to store some maps and sets in my database. What am I doing wrong? Does room not like interfaces or generics?
code: (sorry for all the fields and class name, they are a mixture of English and Czech to not have same names as some java classes):
Converter (only part)
public class MyConverter {
/**
* makes a string like 1;2;3;5;4;8;1;6;8;4 from a collection of integers.
*/
#TypeConverter
public static #NonNull String toString(#NonNull Collection<Integer> c) {
StringBuilder sb = new StringBuilder();
for (Integer item : c) {
sb.append(item.toString() + ";");
}
sb.delete(sb.length()-1,sb.length()-1);
return sb.toString();
}
/**
* makes a Set<Integer> from string like 1;2;3;4;5;6
* #throws NumberFormatException on incorrect input
*/
#TypeConverter
public static#NonNull Set<Integer> toIntegerSet(#NonNull String s) {
Set<Integer> set = new LinkedHashSet<>();
String[] split = s.split(";");
try {
for (String item : split) {
set.add(Integer.parseInt(item));
}
}catch (NumberFormatException e){
throw new NumberFormatException("Could not make set of integers (like 1;2;3;8;7) from \"" + s +"\"");
}
return set;
}
}
Database:
#Database(entities = {SQLUkol.class,SQLPredmet.class,SQLList.class},version = 1)
#TypeConverters({MyConverter.class})
public abstract class AppDatabase extends RoomDatabase {
public abstract MojeDAO mojeDao();
}
One of the entities (getters, setters and constructors not included):
#Entity(primaryKeys = {"id", "list_id"},
indices = {#Index("list_id")},
foreignKeys = #ForeignKey(entity = SQLList.class, parentColumns = "id",
childColumns = "list_id", onDelete = ForeignKey.CASCADE),
tableName = "ukols")
public class SQLUkol implements Comparable<SQLUkol> {
#ColumnInfo(name = "list_id")
private final int listID;
private final int id;
private String title;
#ColumnInfo(name = "title_changed")
private boolean titleChanged = false;
private String notes;
#ColumnInfo(name = "notes_changed")
private boolean notesChanged = false;
private boolean completed;
#ColumnInfo(name = "completed_changed")
private boolean completedChanged = false;
private LocalDate date;
#ColumnInfo(name = "date_changed")
private boolean dateChanged = false;
#Embedded
private final SQLData data;
}

Room does not like generics much. I had to do this:
#TypeConverter
public static String toString1(Map<String, String> m){
...
}
#TypeConverter
public static String toString2(Map<Integer, String> m){
...
}
#TypeConverter
public static String toString3(Set<Integer> s){
...
}
#TypeConverter
public static String toString4(List<Integer> l){
...
}
not just
#TypeConverter
public static String toString(Map m){
...
}
#TypeConverter
public static String toString(Collection<Integer> c){
...
}

Hibernate one to many update with Spring HibernateTemplate

public class AfpProcessSummaryDetail implements Serializable {
private String srNo;
private String fileName;
private String status;
private String location;
private String comments;
private Character convertStatus;
private AfpProcessDetail afpProcessDetail;
public AfpProcessSummaryDetail() {
}
public AfpProcessSummaryDetail(String srNo, String fileName, String status, String location, String comments,
AfpProcessDetail afpProcessDetail) {
this.srNo = srNo;
this.fileName = fileName;
this.status = status;
this.location = location;
this.comments = comments;
this.afpProcessDetail = afpProcessDetail;
}
#ManyToOne
#JoinColumn(name = "PROCESSDETAIL")
public AfpProcessDetail getAfpProcessDetail() {
return afpProcessDetail;
}
AfpProcessDetail
public class AfpProcessDetail implements Serializable {
private String processID;
private String processDate;
private Integer fileCount;
private Integer successCount;
private Integer failureCount;
private Character active;
private Set<AfpProcessSummaryDetail> processSummaryDetails = new HashSet<AfpProcessSummaryDetail>(0);
public AfpProcessDetail() {
}
public AfpProcessDetail(String processID, String processDate, Integer fileCount, Integer successCount,
Integer failureCount) {
this.processID = processID;
this.processDate = processDate;
this.fileCount = fileCount;
this.successCount = successCount;
this.failureCount = failureCount;
}
public AfpProcessDetail(String processID, String processDate, Integer fileCount, Integer successCount,
Integer failureCount, Set<AfpProcessSummaryDetail> processSummaryDetails) {
this.processID = processID;
this.processDate = processDate;
this.fileCount = fileCount;
this.successCount = successCount;
this.failureCount = failureCount;
this.processSummaryDetails = processSummaryDetails;
}
#Column(name = "FAILURECOUNT")
public Integer getFailureCount() {
return failureCount;
}
public void setFailureCount(Integer failureCount) {
this.failureCount = failureCount;
}
#Column(name = "FILECOUNT")
public Integer getFileCount() {
return fileCount;
}
public void setFileCount(Integer fileCount) {
this.fileCount = fileCount;
}
#Column(name = "PROCESSDATE")
public String getProcessDate() {
return processDate;
}
public void setProcessDate(String processDate) {
this.processDate = processDate;
}
#Id
#Column(name = "PROCESSID", unique = true, nullable = false)
public String getProcessID() {
return processID;
}
public void setProcessID(String processID) {
this.processID = processID;
}
#Column(name = "SUCESSCOUNT")
public Integer getSuccessCount() {
return successCount;
}
public void setSuccessCount(Integer successCount) {
this.successCount = successCount;
}
#JoinColumn(name="PROCESSDETAIL")
#OneToMany(cascade=CascadeType.ALL,fetch = FetchType.EAGER)
public Set<AfpProcessSummaryDetail> getProcessSummaryDetails() {
return processSummaryDetails;
}
public void setProcessSummaryDetails(Set<AfpProcessSummaryDetail> processSummaryDetails) {
this.processSummaryDetails = processSummaryDetails;
}
Code for updating
public String updateSummaryDetails(ViewFile viewFile, String codeID) {
if (viewFile != null && codeID != null) {
HibernateTemplate transactionTemplate = new HibernateTemplate(sessionFactory, true);
Object result = transactionTemplate.execute(new HibernateCallback<Object>() {
#Override
public Object doInHibernate(org.hibernate.Session session) throws HibernateException, SQLException {
AfpProcessSummaryDetail processSummary =null,newProcessSummary =null;
AfpProcessDetail processDetail = (AfpProcessDetail)session.get(AfpProcessDetail.class,codeID);
List<FileProperty> fileList = viewFile.getFileList();
Set<AfpProcessSummaryDetail> setProcessSummary=new HashSet<AfpProcessSummaryDetail>();
Set<AfpProcessSummaryDetail> modSetProcessSummary=new HashSet<AfpProcessSummaryDetail>();
setProcessSummary =processDetail.getProcessSummaryDetails();
Iterator<AfpProcessSummaryDetail> itrProcessSumm=setProcessSummary.iterator();
int srNo = 0;
while (itrProcessSumm.hasNext()){
processSummary =(AfpProcessSummaryDetail)itrProcessSumm.next();
for (FileProperty fileProperty : fileList) {
newProcessSummary =new AfpProcessSummaryDetail();
newProcessSummary.setSrNo(codeID + "" + srNo);
newProcessSummary.setFileName(fileProperty.getName());
newProcessSummary.setLocation(fileProperty.getPath());
newProcessSummary.setComments(fileProperty.getComment());
newProcessSummary.setStatus(fileProperty.getStatus());
newProcessSummary.setConvertStatus(fileProperty.getConvertStatus());
newProcessSummary.setAfpProcessDetail(processDetail);
modSetProcessSummary.add(newProcessSummary);
/*if (processSummary.getFileName().trim().equals(fileProperty.getName().trim())){
System.out.println("Element removed");
itrProcessSumm.remove();
modSetProcessSummary.add(newProcessSummary);
break;
}*/
srNo++;
}
}
// setProcessSummary.addAll(modSetProcessSummary);
processDetail.setProcessSummaryDetails(modSetProcessSummary);
processDetail.setFailureCount(viewFile.getExceptionNo());
processDetail.setSuccessCount(viewFile.getSuccessNo());
processDetail.setActive(viewFile.getActive());
transactionTemplate.flush();
session.merge(processDetail);
System.out.println("updated successfully");
return codeID;
}
});
Desired result
I want to perform a one to many update -AfpProcessSummaryDetail which is related to AfpProcessDetail via Set. When I try to replace the set values for update it tries to update the primary key to null. If I don't replace the updates don't take place. If I set cascade it gives error -a different object with the same identifier value was already associated with the session:
[com.aurionpro.convertor.dto.AfpProcessSummaryDetail#15a236f‌​fc961];
nested exception is org.hibernate.NonUniqueObjectException: a
different object with the same identifier value was already associated
with the session.
Please suggest

find highest of each type from Map in java

I am creating the ArrayList of Object, to insert information I use different constructors in that class but I have one type variable that I update with every constructor call. here is what i am doing
public class eProperty {
public String type = null;
public int marks;
public int code;
public String category
public String student_name = null;
public String employee_name = null;
public String o_name = null;
public eProperty(String type, String student_name, int marks) {
this.marks = marks;
this.type = type;
this.student_name = student_marks;
}
public eProperty(String type, String employee_name, int makrs, String category) {
this.marks = marks;
this.type = type;
this.employee_name = employee_name;
this.category = category;
}
public eProperty(String type, int code, int makrs, String o_name) {
this.marks = marks;
this.type = type;
this.mnc = code;
this.o_name = o_name;
}
}
I populate arraylist like this,
ArrayList<eProperty> allData;
eProperty data;
if(type.equals("Student")) {
data = new eProperty(type, "John", 45)
allData.add(data)
}
if(type.equals("Employee")){
data = new eProperty(type, "Vicky", 86, "Developer")
allData.add(data)
} ... other cases also handled like this
Now I want to retrive highest marks for each type and I am stuck here, any help
Thanks

Using loop (sorry for that...) and Predicate from Apache Commons
public static int getHighestMarkByType(ArrayList<eProperty> allData, String type) {
Predicate predicate = new Predicate() {
public boolean evaluate(Object data) {
if ((eProperty) data).getType().equals(type)) {
return true;
} else {
return false;
}
}
};
ArrayList<eProperty> filteredData = (ArrayList<eProperty>) CollectionUtils.select(allData,predicate);
int maxMarks = 0;
for (eProperty data : filteredData) {
if (data.getMarks() > maxMark) {
maxMarks = data.getMark();
}
}
return maxMarks;
}