Spring 豆场线程安全

Question

I have created a spring library in which there is a scheduler that fetches the configurations from config-server and injects it into fields of a bean. Refer diagram below:

The problem is, under heavy load, there might occur thread concurrency issue. How should I prevent that?

Some code:

This is how a user will give a config key

    @AutoConfig("user")
data class ConfigurationWithPrefix (

    @ConfigValue("role")
    val role: String = ""
)

@AutoConfig
data class ConfigurationWithoutPrefix (

    @ConfigValue("user.role")
    val role: String = ""
)

@AutoConfig annotation will make this class a bean. Then I fetch the bean by @AutoConfig annotation and inserts the value in the @ConfigValue key.

field.set(
          bean,
          valueFromConfig
 )

This process has occurred on a different thread, so while inserting field value if my code tried to access the field concurrency issue will be there, how to prevent it?

Answer 1

This is similar to cache read/write with multiple threads, for this kind of problem AtomicReference works better that has semantics similar to volatile without synchronization.

https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/atomic/package-summary.html

Bean definitions can be converted to:

data class ConfigurationWithPrefix (

    @ConfigValue("role")
    val role: AtomicReference<String> = AtomicReference("")
)

@AutoConfig
data class ConfigurationWithoutPrefix (

    @ConfigValue("user.role")
    val role: AtomicReference<String> = AtomicReference("")
)