Spring IoC: identifier per request - spring

Question

I've created this bean in order to get a Supplier<String>:
#Bean
public Supplier<String> auditIdSupplier() {
return () -> String.join(
"-",
"KEY",
UUID.randomUUID().toString()
);
}
As you can see, it's intented to only generate an straightforward identifier string.
Each time, it's called, a new identifier is supplied.
I'd like to change this behavior, in order to get the same generated identifier inside request scope. I mean, first time a request is reached, a new indentifier is generated. From then on, next calls no this Supplier has to return the first generated indentifier inside request scope.
Any ideas?

Answer 1

As it was written in commentary, maybe something like below will work:
#Bean
#RequestScope
public Supplier<String> auditIdSupplier() {
String val = String.join("-","KEY",UUID.randomUUID().toString());
return () -> val;
}

Answer 2

This is my version:
#Component
#Scope(WebApplicationContext.SCOPE_REQUEST)
public class AuditIdPerRequest {
private String key;
#PostConstruct
public void calculateKey() {
this.key = String.join(
"-",
"KEY",
UUID.randomUUID().toString()
);
}
public String getAuditId() {
return this.key;
}
}

Answer 3

You need to configure a request scoped bean
#Configuration
public class MyConfig {
#Bean
#RequestScope
public String myRequestScopedIdentifyer(NativeWebRequest httpRequest) {
// You don't need request as parameter here, but you can inject it this way if you need request context
return String.join(
"-",
"KEY",
UUID.randomUUID().toString());
}
And then inject it where appropriate with either field injection
#Component
public class MyClass {
#Autowired
#Qualifier("myRequestScopedIdentifyer")
private String identifier
or object factory
#Component
public class MyClass {
public MyClass(#Qualifier("myRequestScopedIdentifyer") ObjectFactory<String> identifyerProvider) {
this.identifyerProvider= identifyerProvider;
}
private final ObjectFactory<String> identifyerProvider;
public void someMethod() {
String requestScopedId = identifyerProvider.getObject();
}