Rewrite code to get only several variables - java

I have this code which I would like to use to translate keys and return data to front end:
#GetMapping("pages")
public Page<ContractDTO> pagxes(#RequestParam(value = "page") int page, #RequestParam(value = "size") int size) {
return contractService.findAll(page, size)
//.map(mapper::toDTO);
.map(g -> new ContractDTO(g.getName(), getMerchantName(g.getMerchant_id())));
}
private String getMerchantName(int id) {
Optional<Merchants> obj = merchantService.findById(id);
return obj.get().getName();
}
DTO :
public class ContractDTO {
private Integer id;
.....
private Integer acquirer_id;
private Integer terminal_id;
private String merchant_id;
......
}
How I can rewrite this code .map(g -> new ContractDTO(g.getName(), getMerchantName(g.getMerchant_id()))); to translate from int to String using getMerchantName(int id) only terminal_id and merchant_id and all other variables not to be translated?
I can create constructor in ContractDTO but the code will be huge. Is there some other way?
Error:
The method builder() is undefined for the type ContractDTO

In your case because you want to avoid multiple constructors, You can use a builder design pattern, by using lombok library, it can be more easier, so you can just annotate your class of ContractDTO with this library annotation, and you have every thing to go :
#Getter
#Setter
#NoArgsConstructor
#AllArgsConstructor
#Builder(toBuilder = true)
class ContractDTO {
private Integer id;
private String name;
private Integer acquirerId;
private Integer terminalId;
private String merchantId;
}
then your code can be :
...
.map(g -> ContractDTO.builder()
.name(g.getName())
.merchantName(g.getMerchantId())
.build()
)....

Related

java.lang.NullPointerException due to 'Map<String, Integer>' may not contain keys of type 'Path<String>'

I am facing an issue in a springboot project,
I am trying to retrieve statistics of "Tickets" that are handled ontime using jpa specifications.
Ticket are given a number of days to handle based on the purpose.
Here is the error:
java.lang.NullPointerException: null
at com.ticketcorp.ticket.repository.TicketSpecification.lambda$isOntime$c9c337fb$1(TicketSpecification.java:208) ~[classes/:na]
Which i Believe is to be expected since i got this warning on the same line:
'Map<String, Integer>' may not contain keys of type 'Path<String>'
Here is my Ticket Entity:
#Table(name = "tickets")
public class Ticket {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;
private String code;
private String purpose;
#Lob
#Column(columnDefinition = "TEXT")
private String content;
#Lob
#Column(columnDefinition = "TEXT")
private String solution;
#Lob
#Column(columnDefinition = "TEXT")
private String comment;
private int status;
private LocalDateTime createdAt= LocalDateTime.now();
private LocalDateTime handledAt= LocalDateTime.now();
}
Here is my Ticket Specification:
public class TicketSpecification {
public static Specification<Ticket> isOntime(ArrayList<Purpose> purposes) {
return (root, query, builder) -> {
/*Example of content for nameAndDurationMap: {Suggestion=25, Bug report=1}*/
Map<String, Integer> nameAndDurationMap = PurposeUtils.PurposeArrayToNameDurationMap(purposes);
return builder.le(
builder.diff(
builder.function("unix_timestamp", Long.class, root.get(Ticket_.handledAt)),
builder.function("unix_timestamp", Long.class, root.get(Ticket_.createdAt))
)
, nameAndDurationMap.get(root.get(Ticket_.purpose)) * 86400);/*Line 208*/
};
}
}
Here is my Ticket Service:
#Service
public class TicketService {
#Autowired
private TicketRepository ticketRepository;
public String countTicketsHandledOnTime(){
int handledStatus=2;
Specification<Ticket> allTicketHandledOnTimeQuery =where(TicketSpecification.isHandled(handledStatus)).and(TicketSpecification.isOntime(purposes));
return String.valueOf(ticketRepository.count(allTicketHandledOntimeQuery));
}
}
Here is Purpose POJO Model:
public class Purpose{
private String id;
private String name;
private String description;
private int level;
private int duration;
}
Here is PurposeUtils :
It takes a list of purposes and generate a hashmap of purpose and number of days it should take to handle a ticket of that purpose.
public class PurposeUtils {
public static Map<String, Integer> PurposeArrayToNameDurationMap(ArrayList<Purpose> purposes) {
Map<String, Integer> purposeMap = new HashMap<String, Integer>();
for(Purpose purpose: purposes) {
purposeMap.put(purpose.getName(), purpose.getDuration());
}
return purposeMap;
}
}
I assume you use javax.persistence.criteria.Root in this line:
nameAndDurationMap.get(root.get(Ticket_.purpose)) * 86400);/*Line 208*/
note documentation of Root:
Path< Y > get(String attributeName) Create a path corresponding to the
referenced attribute.
so you ask the map to get the value that indeed is not there
Note that root is not a value holder, it is a for the prdicat creation, so in your predict you will say I want value X(root) to met Y condition
this will become SQL query, so it has to be values that SQL can handle, your code will not be called on every ticket... if you want to do it either makes it iterate every purpose
(
if purpose_x == Ticket_.purpose and le(...)
or purpose_y == Ticket_.purpose and le(...)
)
or move the logic to DB function you can call
code that will give the idea but probably will not run since it dry:
public class TicketSpecification {
public static Specification<Ticket> isOntime(ArrayList<Purpose> purposes){
return (root, query, builder) -> {
List<Predicate> predicates = new ArrayList<>();
for(Purpose purpose: purposes) {
predicates.add(isOntime(purpose.getName(), purpose.getDuration(),root, query, builder);
}
return builder.or(predicates.toArray(new Predicate[0]));
}
}
public static Predicate isOntime(String purposes_name,int purposes_time,Root<Ticket> root, CriteriaQuery<?> query, CriteriaBuilder builder) {
return builder.and(
builder.equal(root.get(Ticket_.purpose),purposes_name)
,
builder.le(
builder.diff(
builder.function("unix_timestamp", Long.class, root.get(Ticket_.handledAt)),
builder.function("unix_timestamp", Long.class, root.get(Ticket_.createdAt))
)
,(purposes_time * 86400);/*Line 208*/
)
);
}
}

MapStruct mapping on objects of type List

I am trying to use MapStruct for a structure similar to the following:
#Data
public class ClassAEntity {
private int id;
private String name;
private String numT;
private List<ClassBEntity) bs;
}
#Data
public class ClassBEntity {
private int id;
private String name;
private String numT;
private List<Other> oc;
}
#Data
public class ClassA {
private int id;
private String name;
private List<ClassB) bs;
}
#Data
public class ClassB {
private int id;
private String name;
private List<Other> oc;
}
In the interface I have added the following mapping:
ClassAEntity map(ClassA classA, String numT)
I get a warning because it can't map numT to classBEntity.numT and I can't add it with #Mapping in the following way:
#Mapping(source = "numT", target = "bs[].numT")
On the other hand I need to ignore the parameter oc of classBEntity because "Other" object contains classAEntity and forms a cyclic object. (because I use oneToMany JPA). I have tried the following:
#Mapping(target = "bs[].oc", ignore = true)
Thank you for your help
MapStruct does not support defining nested mappings for collections. You will have to define more explicit methods.
For example to map numT into bs[].numT and ignore bs[].oc you'll need to do something like:
#Mapper
public MyMapper {
default ClassAEntity map(ClassA classA, String numT) {
return map(classA, numT, numT);
}
ClassAEntity map(ClassA classA, String numT, #Context String numT);
#AfterMapping
default void setNumTOnClassBEntity(#MappingTarget ClassBEntity classB, #Context String numT) {
classB.setNumT(numT);
}
#Mapping(target = "oc", ignore = "true")
ClassBEntity map(ClassB classB);
}

JOOQ + JPA entities

I'm new with JOOQ library and have one thing interesting me so much. I've implemented CRUD service on JOOQ at first and after that I've tried to avoid some duplicate code. For reach that goal I've added JPA repository and also added#Entity annotation to my generated by JOOQ class. And now I still want to use JOOQ for some cases (querying List using filter and sorting and pagination). But something went wrong and now after JOOQ makes a select request I can see nulls in my class's attributes.
I'm getting right count of entities by filter, but class's properties are null after mapping. Is that mapping wrong or I just could't use JOOQ and JPA together for this case?
My abstact class for all entities (as I said, for avoid duplicating code I've refactored some code and now use generics):
#MappedSuperclass
public abstract class AbstractServiceEntity {
private Integer id;
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
}
My JPA class (generated by JOOQ):
/**
* This class is generated by jOOQ.
*/
#SuppressWarnings({ "all", "unchecked", "rawtypes" })
#Entity
#Table(schema = "ref", name = "account")
public class Account extends AbstractServiceEntity implements Serializable {
private static final long serialVersionUID = -162537472;
private Integer id;
private Integer transitId;
private Integer partnerId;
private String currencyCode;
private String descr;
private Long inCredit;
private Long balanceLimit;
private Long outCredit;
private LocalDateTime createdAt;
private LocalDateTime updatedAt;
private Integer transitPartnerId;
public Account() {}
public Account(Account value) {
this.id = value.id;
this.transitId = value.transitId;
this.partnerId = value.partnerId;
this.currencyCode = value.currencyCode;
this.descr = value.descr;
this.inCredit = value.inCredit;
this.balanceLimit = value.balanceLimit;
this.outCredit = value.outCredit;
this.createdAt = value.createdAt;
this.updatedAt = value.updatedAt;
this.transitPartnerId = value.transitPartnerId;
}
public Account(
Integer id,
Integer transitId,
Integer partnerId,
String currencyCode,
String descr,
Long inCredit,
Long balanceLimit,
Long outCredit,
LocalDateTime createdAt,
LocalDateTime updatedAt,
Integer transitPartnerId
) {
this.id = id;
this.transitId = transitId;
this.partnerId = partnerId;
this.currencyCode = currencyCode;
this.descr = descr;
this.inCredit = inCredit;
this.balanceLimit = balanceLimit;
this.outCredit = outCredit;
this.createdAt = createdAt;
this.updatedAt = updatedAt;
this.transitPartnerId = transitPartnerId;
}
And my method extracting entities from DB:
#Repository
#RequiredArgsConstructor
public class JooqAccountRepository {
private final DSLContext jooq;
public List<Account> findAll(Condition filterCondition, SortField[] sortFields, Integer partnerId, Integer limit, Integer offset) {
return jooq.selectFrom(ACCOUNT)
.where(ACCOUNT.PARTNER_ID.equal(partnerId))
.and(filterCondition)
.orderBy(sortFields)
.limit(limit)
.offset(offset)
.fetchInto(Account.class);
}
public Integer findAccountsCount(Integer partnerId) {
return jooq.selectCount().from(ACCOUNT)
.where(ACCOUNT.PARTNER_ID.equal(partnerId))
.fetchOne(0, Integer.class);
}
}
As a result of my searches - I've made a mistake with annotations in Account class. If you want use these frameworks together, you should use #Column on entity's properties or setting your jooq's codegen plugin in different way)
This resource was usefull for me

JPA AttributeConverter search predicate in specification

I am trying to have a class that has a certain list of objects (specified by another class) persisted in the database as a string (use JPA Converter - all good).
And then I want to use Specification to search inside that string.
What is the best way to create the predicates? I don't seem to understand the connection bettween the AttributeConverter and the Expression in the Specification.
The parent class:
#Entity #Table
public class A {
#Column #Id #GeneratedValue(strategy=GenerationType.AUTO)
private Long id;
#Column
private String name;
#Enumerated(EnumType.STRING)
private SomeType type;
#Column(length=1000) #Convert(converter = BConverter.class)
private List<B> bList;
private Integer no;
}
The listed object class:
public class B{
private String type;
private Integer quantity;
}
The converter:
#Converter
public class BConverter implements AttributeConverter<List<B>, String> {
private static final String SEPARATOR = ":";
private static final String LIST_SEPARATOR = ";";
#Override public String convertToDatabaseColumn(List<B> bList) {
return bList.stream().map(e->convertToString(e)).collect(Collectors.joining(LIST_SEPARATOR));
}
#Override public List<B> convertToEntityAttribute(String str) {
if(str==null || str.isEmpty() ) return null;
return Arrays.stream(str.split(LIST_SEPARATOR)).map(e->convertFromString(e)).collect(Collectors.toList());
}
private String convertToString(B b){
if(entity==null) return null;
return b.getType().toString() +SEPARATOR+ b.getQuantity().toString();
}
private B convertFromString(String subStr){
if(subStr==null || subStr.isEmpty() ) return null;
String[] pair = subStr.split(SEPARATOR);
return new B(pair[0],Integer.valueOf(pair[1]));
}
}
In the database should look something like:
Table A:
id: 1;
name: "Some Name";
type: "THISTYPE";
blist: "TYPE1:11;TYPE2:22";
no: 0;
id: 2;
name: "Other Name";
type: "THISTYPE";
blist: "TYPE1:45;TYPE2:56";
no: 12;
I would then like to create Specifications to search over this table for the attributes inside the bList.
For example, search by an entity that contains a B object where type=TYPE1 and a quantity>=30.
public static Specification<A> customSpecification(String type, Integer value) {
return (root, query, builder) -> ///?????????
}
Is there a way to use such specifications where the DB attribute is a String but JAVA only sees the objects?

Constructor method must contain all instance variables

Many times I'm faced with a class which constructor method must contain list of arguments that is identical with the list of class instance variables.
As you see in the example there is "SOME" code to make this hapend.
I'm wondering how can I make this process less painful?
Example:
public class VimeoUser extends Schema {
#Getter #Setter private String uri;
#Getter #Setter private String name;
#Getter #Setter private String link;
#Getter #Setter private String location;
#Getter #Setter private String bio;
#Getter #Setter private String createdTime;
#Getter #Setter private String account;
#Getter #Setter private Map<String,Integer> statistics = new HashMap<>();
#Getter #Setter private List<Website> websites = new ArrayList<>();
#Getter #Setter private List<Portrait> portraits = new ArrayList<>();
public VimeoUser(
String uri,
String name,
String link,
String location,
String bio,
String createdTime,
String account,
Map<String,Integer> statistics,
List<Website> websites,
List<Portrait> portraits){
this.uri = uri;
this.name = name;
this.link = link;
this.location = location;
this.bio = bio;
this.createdTime = createdTime;
this.account = account;
this.statistics = statistics;
this.websites = websites;
this.portraits = portraits;
}
}
It is possible to use a pattern named Builder. It is explained in this question
Basically it works as following:
Create an inner static class Builder
Create a private constructor that take as an argument an object of type Builder
In the Builder class add methods that set a single value and returns this (current reference to instance of the Builder class)
In the body of the constructor of your class use the values passed in the Builder to set each property
add a method build in the Builder that calls the private constructor of your class
Here is an example:
public class NutritionalFacts {
private int sodium;
private int fat;
private int carbo;
public class Builder {
private int sodium;
private int fat;
private int carbo;
public Builder(int s) {
this.sodium = s;
}
public Builder fat(int f) {
this.fat = f;
return this;
}
public Builder carbo(int c) {
this.carbo = c;
return this;
}
public NutritionalFacts build() {
return new NutritionalFacts(this);
}
}
private NutritionalFacts(Builder b) {
this.sodium = b.sodium;
this.fat = b.fat;
this.carbo = b.carbo;
}
}
and to use it do the following:
NutritionalFacts nutritionalFacts = new NutritionalFacts.Builder()
.fat(200).carbo(50).build();
Using this pattern instead of pojo with setter and getter is useful because it is possible to use it also to build immutable objects (objects with all final fields). An immutable object is useful if you need to share it on a multithreaded environment because it is not necessary to synchronize the access to it.
Additionally it is possible to add some controls in the build method to be sure that all fields are setted as expected.
I guess writing pojos for database modelling does not necessarily needs constructor other than default no-arg constructor. If anyway required in some situations, Getters and setters can be used.
Builder pattern
If you want create a object with more readable way, you can use a simple builder pattern. Lombok support this such as #Getter or #Setter. You just add #Builder annotation and everything should works fine.
#Getter
#Builder
public class SomeClass {
private final String valueOne;
private final String valueTwo;
}
And then you can create object in this way.
SomeClass someClass = SomeClass.builder()
.valueOne("one")
.valueTwo("two")
.build();
Fluent accessors method
Alternative way to create a class is using #Accessors annotation with fluent = true. Then you can create a empty object and set the value what you needed in simple way.
#Getter
#Setter
#Accessors(fluent = true)
public class SomeClass {
private String valueOne;
private String valueTwo;
}
Simple sample using this way.
SomeClass someClass = new SomeClass()
.valueOne("one")
.valueTwo("two");
I see you are already using Lombok. There is a #AllArgsConstructor class-level annotation that will generate the constructor for you. If you want the default constructor, too, use #NoArgsConstructor additionally.
More info on the constructor-generating annotations here.

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