Retrieve private class member name

Question

I am designing a Hibernate's entity Pre-Update Event Listener with Java 8.

I've created a StateTracker class that, from the PreUpdateEvent, gets the entity's new and old states and the parameters name. This class maps the parameters names to the corresponding pair of old and new states and a lazy evaluated Boolean hasChanged and make querying the map by key (which is of type String) available through a public method.

Problem is: I need to check if a specific property from an entity A, say it is named var, will have it's state changed by the update event. Naturally this can be done like this:

void foo(PreUpdateEvent event) {
    StateTracker stateTracker(event);
    if(stateTracker.isPropertyModified("var") {
        /* do stuff... */
    }
}

I know I can't always save the world, but if someone ever changes var name to catastrophe in A, then the above code will be broken, because even the smarter of the refactoring tools won't see that the String "var" is meant to represent the name of the parameter var (now catastrophe).

I am accepting that there is no better way out of this situation, but I want to be sure that is no way to get a variable name through reflection or something.

Ideally, this would work like this:

void foo(PreUpdateEvent event) {
    StateTracker stateTracker(event);
    if(stateTracker.isPropertyModified(A.class.var.getName()) { // Magic!
        /* do stuff... */
    }
}

Maybe some wizardry in the field of annotation processing could perform such magic...

Best bet is to have a unit test ensure that the field name used is correct. — Peter Gelderbloem, Oct 24 '16 at 16:53
@PeterGelderbloem great suggestion, I'm going with unit tests — Rodrigo Oliveira, Nov 02 '16 at 15:38

score 0 · Answer 1 · answered Oct 24 '16 at 16:53

0

Yes go through simply reflection, iterate through tabs, create a hashset key is the field name and value is value of field then each time iterate through your set and if the any item state changed/removed flag the entity as updated

answered Oct 24 '16 at 16:53

HRgiger

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or instead of value you can use a generated hash of value will be less memory consuming – HRgiger Oct 24 '16 at 16:54
Sorry, but I can't figure it out how this solves the problem. I do not want to flag the entity as updated, I want to filter out relevant updates to the entity based on specific fields being updated. Creating a hashset won't put away the risk of someone modifying a field name and render code that uses the old name in StateTracker broken. – Rodrigo Oliveira Nov 02 '16 at 15:38

Retrieve private class member name

1 Answers1