Java 泛型 : Is this safe enough?

Question

考虑以下代码片段:

public interface FieldEnum {
    public String getEnumName();
}

---

public enum InvoiceStatus implements FieldEnum {
    UNCHECKED("unchecked"),
    ERROR("error"),
    OK("ok");

    private final String enumName;

    private InvoiceStatus(final String enumName) {
        this.enumName = enumName;
    }

    @Override
    public String getEnumName() {
        return enumName;
    }
}

---

private InvoiceBean(final Integer invoiceId, final Integer businessPartnerId, final String invoiceNumber, final Date invoiceDate, final BigDecimal priceExclVAT, final BigDecimal VAT, final BigDecimal priceInclVAT, final BigDecimal paymentDiscount, final InvoiceStatus status) {
    this.invoiceId = invoiceId;
    this.businessPartnerId = businessPartnerId;
    this.invoiceNumber = invoiceNumber;
    this.invoiceDate = invoiceDate;
    this.priceExclVAT = priceExclVAT;
    this.VAT = VAT;
    this.priceInclVAT = priceInclVAT;
    this.paymentDiscount = paymentDiscount;
    this.status = status;
}

public InvoiceBean(final ResultSet rs) throws SQLException {
    this(rs.getInt(1), rs.getInt(2), rs.getString(3), rs.getDate(4), rs.getBigDecimal(5), rs.getBigDecimal(6), rs.getBigDecimal(7), rs.getBigDecimal(8), EnumConverter.convert(rs.getString(9), InvoiceStatus.values()));
}

下面的代码安全吗？

public class EnumConverter {
    public static <T extends FieldEnum> T convert(String enumName, T[] enumValues) {
        for (T enumValue : enumValues) {
            if (enumName.equals(enumValue.getEnumName())) {
                return enumValue;
            }
        }
        throw new IllegalStateException("orm.enums.EnumConverter.convert: No suitable enum has been found. enumName = " + enumName + " fieldEnums = " + enumValues);
    }
}

或者使用它会有什么好处吗？ (注意添加 Class<T> clazz 参数)

public class EnumConverter {
    public static <T extends FieldEnum> T convert(String enumName, T[] enumValues, Class<T> clazz) {
        for (T enumValue : enumValues) {
            if (enumName.equals(enumValue.getEnumName())) {
                return enumValue;
            }
        }
        throw new IllegalStateException("orm.enums.EnumConverter.convert: No suitable enum has been found. enumName = " + enumName + " fieldEnums = " + enumValues);
    }
}

然后通过EnumConverter.convert(rs.getString(9), InvoiceStatus.values(), InvoiceStatus.class)调用它当然。

问候。

Answer 1

一个简单的答案是忘记 EnumConverter 而是使用 InvoiceStatus.valueOf(rs.getString(9));