CODEWITHSUNDEEP
javaspringannotations
itsme
itsme

Reputation: 852

set property of base class in derived class with spring annotations

I've a base class with a property that should be set in the derived class. I've to use annotations. How's that possible? I know how do this with xml spring configurations, but not with annotations, because I've to write them at the property?

Here's some example code:

public class Base {
    // This property should be set
    private String ultimateProperty;

    // ....
}

public class Hi extends Base {
    // ultimate property should be "Hi" in this class
    // ...
}

public class Bye extends Base {
    // ultimate property should be "Bye" in this class
    // ...
}

How is this possible with annotations?

Upvotes: 1

Views: 4435

Answers (2)

Ryan Stewart
Ryan Stewart

Reputation: 128779

Some options depending on what else Base has:

class Base {
    private String ultimateProperty;

    Base() {
    }

    Base(String ultimateProperty) {
        this.ultimateProperty = ultimateProperty;
    }

    public void setUltimateProperty(String ultimateProperty) {
        this.ultimateProperty = ultimateProperty;
    }
}

class Hi extends Base {
    @Value("Hi")
    public void setUltimateProperty(String ultimateProperty) {
        super.setUltimateProperty(ultimateProperty);
    }
}

class Bye extends Base {
    public Bye(@Value("Bye") String ultimateProperty) {
        setUltimateProperty(ultimateProperty);
    }
}

class Later extends Base {
    public Later(@Value("Later") String ultimateProperty) {
        super(ultimateProperty);
    }
}

class AndAgain extends Base {
    @Value("AndAgain")
    private String notQuiteUltimate;

    @PostConstruct
    public void doStuff() {
        super.setUltimateProperty(notQuiteUltimate);
    }
}

Of course, if you really just want the name of the class there, then

class SmarterBase {
    private String ultimateProperty = getClass().getSimpleName();
}

Upvotes: 2

chrislovecnm
chrislovecnm

Reputation: 2611

Annotations for fields are linked directly to the source code in the class. You may be able to do what you are looking for via Spring EL with-in an @Value annotation, but I think the complexity overrides the value.

A pattern you may want to consider is using @Configuration annotation to programmatically setup your application context. That way you can define what is injected into the base class.

Upvotes: 0

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