How to error code representation using enum in java

How to error code representation using enum in java

Here is the solution using your Enum that I typically employ to deal with error codes as you have explained in your scenario.

import java.util.HashMap;

import java.util.Map;

public class EnumSample {

    public static enum LoginErrorCode {

        EMAIL_OR_PASSWORD_INCORRECT("101"), EMAIL_INCORRECT("102"), UNKNOWN_ERROR_CODE("---");

        private static Map<String, LoginErrorCode> codeToEnumMap;

        private final String code;

        LoginErrorCode(String code) {

            this.code = code;

        }

        public String getCode() {

            return code;

        }

        /**

         * Looks up enum based on code.  If code was not registered as enum, it returns UNKNOWN_ERROR_CODE

         * @param code

         * @return

         */

        public static LoginErrorCode fromCode(String code) {

            // Keep a hashmap of mapping between code and corresponding enum as a cache.  We need to initialize it only once

            if (codeToEnumMap == null) {

                codeToEnumMap = new HashMap<String, EnumSample.LoginErrorCode>();

                for (LoginErrorCode aEnum : LoginErrorCode.values()) {

                    codeToEnumMap.put(aEnum.getCode(), aEnum);

                }

            }

            LoginErrorCode enumForGivenCode = codeToEnumMap.get(code);

            if (enumForGivenCode == null) {

                enumForGivenCode = UNKNOWN_ERROR_CODE;

            }

            return enumForGivenCode;

        }

    }

    public static void main(String[] args) {

        System.out.println( LoginErrorCode.fromCode("101")); //Prints EMAIL_OR_PASSWORD_INCORRECT

        System.out.println( LoginErrorCode.fromCode("102")); //Prints EMAIL_INCORRECT

        System.out.println( LoginErrorCode.fromCode("999")); //Prints UNKWNOWN_ERROR_CODE

    }

}