Meaning of a key as an argument to the Cacheable annotation

Question

I am trying to use the Spring @Cacheable annotation.

Lets look at:

@Cacheable(value = "employee", key = "#surname")
public Person findEmployeeBySurname(String firstName, String surname, int age) {

    return new Person(firstName, surname, age);

}

Am I right that if I add 2 people with the same surname then only one will be saved in the cache, and the method will return incorrect results sometimes?

When should I specify this argument?

How does spring create the key if I don't specify it explicitly(as I understand I should know it when I use CasheEvict and CashPut annotations)?

Answer 1

JB Nizet is right, it is clearly in the documentation he linked to!

35.3.1 @Cacheable annotation ...

Default Key Generation

Since caches are essentially key-value stores, each invocation of a cached method needs to be translated into a suitable key for cache access. Out of the box, the caching abstraction uses a simple KeyGenerator based on the following algorithm:

 If no params are given, return SimpleKey.EMPTY. If only one param is given, return that instance. If more the one param is given, return a SimpleKey containing all parameters. 

It is the last of the three cases that is importent for your mehtods, wihout cache parameter