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Reputation: 1249

Exception handling within enum instance

How to handle exceptions within Enum instances in Java? I have an enum class as follows:

public enum TagEnum {

    EDIT_ACCESS("feature.edit", GlobalAccess.getEditStatus());

    private String key;
    private Boolean featureStatus;

    private TagEnum(String key, Boolean status) {
        this.key=key;
        this.featureStatus=status;
    }

}

In above scenario getEditStatus() method of GlobalAccess class throws Exception:

public static Boolean getEditStatus() throws Exception {
    ...
}

Above TagEnum enum gave a compilation error because the enum instance cannot handle GlobalAccess.getEditStatus() method. Please guide me on how to pass java methods that throws exceptions, as an argument inside an Enum instance.

Upvotes: 0

Views: 8523

Answers (2)

Rudi Kershaw
Rudi Kershaw

Reputation: 13012

You can't handle an exception during class member declaration and declaring an enum in this sense is much the same as declaring a class.

You will have to move the GlobalAccess.getEditStatus() call into a block, constructor, or method to handle any exceptions that are thrown. As an example, you could move it into the constructor like so;

private TagEnum(String key) {
    this.key=key;
    try{
        this.featureStatus = GlobalAccess.getEditStatus();
    } catch(Exception e) { 
        // Handle the exception here. 
    }
}

Alternatively Initialization Blocks were created for more or less exactly this issue. To allow you handle logic, errors and exceptions during class(or enum) member declaration.

Upvotes: 1

sp00m
sp00m

Reputation: 48837

You could implement a dedicated method which will be able to handle this exception, e.g.:

public enum TagEnum {

    EDIT_ACCESS("feature.edit") {
        @Override
        protected Boolean initFeatureStatus() {
            try {
                return GlobalAccess.getEditStatus();
            } catch (Exception e) {
                // handle it there
                return null;
            }
        }
    };

    private String key;
    private Boolean featureStatus;

    private TagEnum(String key) {
        this.key = key;
        this.featureStatus = initFeatureStatus();
    }

    protected abstract Boolean initFeatureStatus();

}

Upvotes: 0

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