Can I have a non default multiple argument constructor in toplink. For example
public class Employee {
private String empId;
public Employee(String empId) {
this.empId = empId;
}
}
Yes, however a default constructor must still be available for toplink as well. Toplink uses the default constructor and setters/properties to initialize your object.
Related
I've provided a sample project to elucidate this problem: https://github.com/nmarquesantos/spring-mongodb-reactive-indexes
According to the spring mongo db documentation (https://docs.spring.io/spring-data/mongodb/docs/current/reference/html/#mapping-usage):
the #Indexed annotation tells the mapping framework to call createIndex(…) on that property of your document, making searches faster. Automatic index creation is only done for types annotated with #Document.
In my Player class, we can observe the both the #Document and #Indexed annotation:
#Document
public class Player {
#Id
private String id;
private String playerName;
#Indexed(name = "player_nickname_index", unique = true)
private String nickname;
public Player(String playerName, String nickname) {
this.id = UUID.randomUUID().toString();
this.playerName = playerName;
this.nickname = nickname;
}
public String getPlayerName() {
return playerName;
}
public void setPlayerName(String playerName) {
this.playerName = playerName;
}
public String getNickname() {
return nickname;
}
public void setNickname(String nickname) {
this.nickname = nickname;
}
}`
And in my application class, i'm inserting oneelement to check the database is populated successfully:
#PostConstruct
public void seedData() {
var player = new Player("Cristiano Ronaldo", "CR7");
playerRepository.save(player).subscribe();
}
If I check MongoDb after running my application, I can see the collection and the element created successfully.
The unique index for nickname is not created. I can only see an index created for the #Id attribute. Am I missing anything? Did I mis-interpret the documentation?
The Spring Data MongoDB version come with Spring Boot 2.3.0.RELEASE is 3.0.0.RELEASE. Since Spring Data MongoDB 3.0, the auto-index creation is disabled by default.
To enable auto-index creation, set spring.data.mongodb.auto-index-creation = true or if you have custom Mongo configuration, override the method autoIndexCreation
#Configuration
public class CustomMongoConfig extends AbstractMongoClientConfiguration {
#Override
public boolean autoIndexCreation() {
return true;
}
// your other configuration
}
I've faced this problem when upgrading the spring boot version to 2.3.x and overriding this method on the config class solved it (what #yejianfengblue said above)
#Override
public boolean autoIndexCreation() {
return true;
}
Is it possible to use Jersey with Moxy to/from Json and Java 8 Optionals?
How to configure it?
You can declare following class:
public class OptionalAdapter<T> extends XmlAdapter<T, Optional<T>> {
#Override
public Optional<T> unmarshal(T value) throws Exception {
return Optional.ofNullable(value);
}
#Override
public T marshal(Optional<T> value) throws Exception {
return value.orElse(null);
}
}
And use like this:
#XmlRootElement
public class SampleRequest {
#XmlElement(type = Integer.class)
#XmlJavaTypeAdapter(value = OptionalAdapter.class)
private Optional<Integer> id;
#XmlElement(type = String.class)
#XmlJavaTypeAdapter(value = OptionalAdapter.class)
private Optional<String> text;
/* ... */
}
Or declare in package-info.java and remove #XmlJavaTypeAdapter from POJOs:
#XmlAccessorType(XmlAccessType.FIELD)
#XmlJavaTypeAdapters({
#XmlJavaTypeAdapter(type = Optional.class, value = OptionalAdapter.class)
})
But here are some drawbacks:
Adapter above can only work with simple types like Integer, String, etc. that can be parsed by MOXY by default.
You have to specify #XmlElement(type = Integer.class) explicitly to tell the parser type are working with, otherwise null values would be passed to adapter's unmarshal method.
You miss the opportunity of using adapters for custom types, e.g. custom adapter for java.util.Date class based on some date format string. To overcome this you'll need to create adapter something like class OptionalDateAdapter<String> extends XmlAdapter<String, Optional<Date>>.
Also using Optional on field is not recommended, see this discussion for details.
Taking into account all the above, I would suggest just using Optional as return type for your POJOs:
#XmlRootElement
public class SampleRequest {
#XmlElement
private Integer id;
public Optional<Integer> getId() {
return Optional.ofNullable(id);
}
public void setId(Integer id) {
this.id = id;
}
}
I can't get Spring Data Rest with class inheritance working.
I'd like to have a single JSON Endpoint which handles all my concrete classes.
Repo:
public interface AbstractFooRepo extends KeyValueRepository<AbstractFoo, String> {}
Abstract class:
#JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.PROPERTY, property = "type")
#JsonSubTypes({
#JsonSubTypes.Type(value = MyFoo.class, name = "MY_FOO")
})
public abstract class AbstractFoo {
#Id public String id;
public String type;
}
Concrete class:
public class MyFoo extends AbstractFoo { }
Now when calling POST /abstractFoos with {"type":"MY_FOO"}, it tells me: java.lang.IllegalArgumentException: PersistentEntity must not be null!.
This seems to happen, because Spring doesn't know about MyFoo.
Is there some way to tell Spring Data REST about MyFoo without creating a Repository and a REST Endpoint for it?
(I'm using Spring Boot 1.5.1 and Spring Data REST 2.6.0)
EDIT:
Application.java:
#SpringBootApplication
#EnableMapRepositories
public class Application {
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
}
}
I'm using Spring Boot 1.5.1 and Spring Data Release Ingalls.
KeyValueRepository doesn't work with inheritance. It uses the class name of every saved object to find the corresponding key-value-store. E.g. save(new Foo()) will place the saved object within the Foo collection. And abstractFoosRepo.findAll() will look within the AbstractFoo collection and won't find any Foo object.
Here's the working code using MongoRepository:
Application.java
Default Spring Boot Application Starter.
#SpringBootApplication
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
AbstractFoo.java
I've tested include = JsonTypeInfo.As.EXISTING_PROPERTY and include = JsonTypeInfo.As.PROPERTY. Both seem to work fine!
It's even possible to register the Jackson SubTypes with a custom JacksonModule.
IMPORTANT: #RestResource(path="abstractFoos") is highly recommended. Else the _links.self links will point to /foos and /bars instead of /abstractFoos.
#JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.EXISTING_PROPERTY, property = "type")
#JsonSubTypes({
#JsonSubTypes.Type(value = Foo.class, name = "MY_FOO"),
#JsonSubTypes.Type(value = Bar.class, name = "MY_Bar")
})
#Document(collection="foo_collection")
#RestResource(path="abstractFoos")
public abstract class AbstractFoo {
#Id public String id;
public abstract String getType();
}
AbstractFooRepo.java
Nothing special here
public interface AbstractFooRepo extends MongoRepository<AbstractFoo, String> { }
Foo.java & Bar.java
#Persistent
public class Foo extends AbstractFoo {
#Override
public String getType() {
return "MY_FOO";
}
}
#Persistent
public class Bar extends AbstractFoo {
#Override
public String getType() {
return "MY_BAR";
}
}
FooRelProvider.java
Without this part, the output of the objects would be separated in two arrays under _embedded.foos and _embedded.bars.
The supports method ensures that for all classes which extend AbstractFoo, the objects will be placed within _embedded.abstractFoos.
#Component
#Order(Ordered.HIGHEST_PRECEDENCE)
public class FooRelProvider extends EvoInflectorRelProvider {
#Override
public String getCollectionResourceRelFor(final Class<?> type) {
return super.getCollectionResourceRelFor(AbstractFoo.class);
}
#Override
public String getItemResourceRelFor(final Class<?> type) {
return super.getItemResourceRelFor(AbstractFoo.class);
}
#Override
public boolean supports(final Class<?> delimiter) {
return AbstractFoo.class.isAssignableFrom(delimiter);
}
}
EDIT
Added #Persistent to Foo.java and Bar.java. (Adding it to AbstractFoo.java doesn't work). Without this annotation I got NullPointerExceptions when trying to use JSR 303 Validation Annotations within inherited classes.
Example code to reproduce the error:
public class A {
#Id public String id;
#Valid public B b;
// #JsonTypeInfo + #JsonSubTypes
public static abstract class B {
#NotNull public String s;
}
// #Persistent <- Needed!
public static class B1 extends B { }
}
Please see the discussion in this resolved jira task for details of what is currently supported in spring-data-rest regarding JsonTypeInfo. And this jira task on what is still missing.
To summarize - only #JsonTypeInfo with include=JsonTypeInfo.As.EXISTING_PROPERTY is working for serialization and deserialization currently.
Also, you need spring-data-rest 2.5.3 (Hopper SR3) or later to get this limited support.
Please see my sample application - https://github.com/mduesterhoeft/spring-data-rest-entity-inheritance/tree/fixed-hopper-sr3-snapshot
With include=JsonTypeInfo.As.EXISTING_PROPERTY the type information is extracted from a regular property. An example helps getting the point of this way of adding type information:
The abstract class:
#Entity #Inheritance(strategy= SINGLE_TABLE)
#JsonTypeInfo(use=JsonTypeInfo.Id.NAME,
include=JsonTypeInfo.As.EXISTING_PROPERTY,
property="type")
#JsonSubTypes({
#Type(name="DECIMAL", value=DecimalValue.class),
#Type(name="STRING", value=StringValue.class)})
public abstract class Value {
#Id #GeneratedValue(strategy = IDENTITY)
#Getter
private Long id;
public abstract String getType();
}
And the subclass:
#Entity #DiscriminatorValue("D")
#Getter #Setter
public class DecimalValue extends Value {
#Column(name = "DECIMAL_VALUE")
private BigDecimal value;
public String getType() {
return "DECIMAL";
}
}
I am doing Spring Rest Api project with Spring 4.x
This Works:
Controller.java
#PostMapping("newTransaction")
TransactionRequestModel insertNewTransaction(#RequestBody TransactionRequestModel model){
//do something
}
TransactionRequestModel.java
public class TransactionRequestModel {
private int id;
private List<KeyValue> keyValueList;
public TransactionRequestModel(){}
//default constructor
//getter-setter
}
KeyValue.java
public class KeyValue {
String key;
String value;
//default constructor
//setter-getter
}
Request Body Json
{
"id": 1
"keyValueList": [
{
"key": "dummy",
"value": "dummy"
}
]
}
Spring message converter using jackson is working fine.
This Won't:
When i change TransactionRequestModel.java to following (and delete KeyValue.java)
public class TransactionRequestModel {
public class KeyValue {
String key;
String value;
//default constructor
//setter-getter
}
private int id;
private List<KeyValue> keyValueList;
public TransactionRequestModel(){}
//default constructor
//getter-setter
}
means, making KeyValue an inner class, got following error.
org.springframework.http.converter.HttpMessageNotReadableException:
Could not read document: No suitable constructor found for type
[simple type, class
com.example.model.TransactionRequestModel$KeyValue]: can not
instantiate from JSON object (missing default constructor or creator,
or perhaps need to add/enable type information?)
Why?
All the related post in SO mentions the first scenario. I would like to know why this wont work. Please help.
You have to make your inner class static.
public class TransactionRequestModel {
public static class KeyValue {
String key;
String value;
//default constructor
//setter-getter
}
private int id;
private List<KeyValue> keyValueList;
public TransactionRequestModel(){}
//default constructor
//getter-setter
}
I have the following MongoDB Repository
public interface TeamRepository extends MongoRepository<Team, TeamId> {
....
}
And the following classes:
public abstract class DbId implements Serializable {
#Id
private final String id;
public DbId(final String id) { this.id = id;}
public String getId() { return id;}
}
public class TeamId extends DbId {
public TeamId(final String id) {
super(id)
}
}
As you can see, I have like a custom id for the repository (I have MongoRepository instead of something like MongoRepository). But, when I am trying to save a Team object, I get an error saying that MongoDB does not know how to generate DBId. Any clue?
MongoDb (or any database) would not know how to generate a string ID without you informing it what the value of the string is.
The default #Id is a string representation of ObjectId, which can be auto-generated by MongoDB. If you are changing the type of string ObjectId to a class, then at least the class needs to define:
** Conversion to string (serialisable), for example:
#Override
public String toString() {
return String.format(
"TeamID[uniqueString=%s]",
myUniqueString);
}
** How to generate the Id.
You can define a method in your TeamRepository i.e. save() to specify how your string can be generated. Alternatively you can check out
https://www.mkyong.com/mongodb/spring-data-mongodb-auto-sequence-id-example/
Where the example specify getNextSequenceId() to generate NumberLong custom id. Hopefully that guides you to your answer.