类“…”必须声明为“抽象”。 Checkstyle

Question

I have this warning on most of my classes and not sure why is that. This happens on both public normal classes and final classes which have private constructors, some no constructor at all. I tried changing my private class methods to protected, doesn't help.
Any suggestions on how to turn this off?

Here's a class example

public final class PlanBenefitManagerAssembler {

    private static final Logger LOGGER = Logger.getLogger(PlanBenefitManagerAssembler.class);

    /**
     * No Instance of the this class is allowed.
     */
    private PlanBenefitManagerAssembler() {

    }

    public static List<BenefitDecisionDetailsBean> assembleBenefitDecisionDetailsBean(
            List<BenefitDetails> benefitDecisionDetailsList, int relationalSequenceNumber) {

        LOGGER.debug("Enter assembleBenefitDecisionDetailsBean");
        List<BenefitDecisionDetailsBean> benefitDecisionDetailsBeanList = new ArrayList<BenefitDecisionDetailsBean>();

        for (BenefitDetails benefitDecisionDetails : benefitDecisionDetailsList) {
            BenefitDecisionDetailsBean benefitDecisionDetailsBean = new BenefitDecisionDetailsBean();
            benefitDecisionDetailsBean.setBenefitTypeCode(benefitDecisionDetails.getBenefitTypeCode());
            benefitDecisionDetailsBean.setRelationSequenceNumber(relationalSequenceNumber);
            benefitDecisionDetailsBean.setBenefitStatusDescription(
                    benefitDecisionDetails.getBenefitStatusDescription());
            benefitDecisionDetailsBean.setBenefitStatusCode(benefitDecisionDetails.getBenefitStatusCode());
            benefitDecisionDetailsBean.setBenefitUnderwritingStatusCode(
                    benefitDecisionDetails.getBenefitUnderwritingStatusCode());
            benefitDecisionDetailsBean.setBenefitUnderwritingStatusDescription(
                    benefitDecisionDetails.getBenefitUnderwritingStatusDescription());
            benefitDecisionDetailsBean.setBenefitChangeReasonCode(
                    String.valueOf(benefitDecisionDetails.getBenefitChangeReasonCode()));
            benefitDecisionDetailsBean.setBenefitChangeReasonDescription(
                    benefitDecisionDetails.getBenefitChangeReasonDescription());
            benefitDecisionDetailsBean.setComponentNumber(benefitDecisionDetails.getBenefitNumber());

            benefitDecisionDetailsBean.setBenefitVisible(benefitDecisionDetails.isExplicitBenefitDecisionRequired());

            benefitDecisionDetailsBean.setModelChanged(false);

            // * Set BenefitLoading and BenefitExclusion
            List<ExclusionDetailsBean> exclusionDetailsBeanList =
                    PlanBenefitManagerAssembler.assembleExclusionDetailsList(benefitDecisionDetails
                            .getBenefitExclusionsDetailsList().getBenefitExclusionsDetailsList());

            List<LoadingDetailsBean> loadingDetailsBeanList =
                    PlanBenefitManagerAssembler.assembleLoadingDetailsList(benefitDecisionDetails
                            .getBenefitLoadingsDetailsList().getBenefitLoadingsDetailsList());

            benefitDecisionDetailsBean.setExclusionDetailsBeanList(exclusionDetailsBeanList);
            benefitDecisionDetailsBean.setLoadingDetailsBeanList(loadingDetailsBeanList);

            benefitDecisionDetailsBeanList.add(benefitDecisionDetailsBean);         
        }

        LOGGER.debug("Exit assembleBenefitDecisionDetailsBean");

        return benefitDecisionDetailsBeanList;
    }
}

Answer 1

You can always turn the warnings off, but they generally are here for a reason :)

• Do you intend to make them abstract classes ? If so, declare them that way.
• Will you need to instantiate them at some point ? If so, add a public constructor.

I'm pretty sure this will solve your problem.

Answer 2

When Checkstyle produces a warning the warning text should include a short rule name which will allow you to look up the exact rule that is being triggered. "DesignForExtension", for example.

Given the rule name, you can look up more detail on what it means in the Checkstyle documentation: http://checkstyle.sourceforge.net/availablechecks.html

Post the full details of the rule being triggered and someone might be able to help.

Answer 3

On sourceforge it says that the AbstractClassName rule uses the following regex:

^Abstract.*$|^.*Factory$

This causes classes with a name starting with 'Abstract' or ending with 'Factory' to be flagged. I get the 'Abstract..' part of that, but why should all '..Factory' classes be abstract? Sometimes I create factories which use dependencies to do their work so I need an instance to inject into.

This however does not explain your case. I tried your example class and did not get any Checkstyle warning (I am using the Eclipse Checkstyle Plug-in version 5.3.0.201012121300).

Are you sure you are getting the AbstractClassName warning for this class? Which version of Checkstyle are you using?