Wsrtjtyk

I have Enum class as given below

public enum AlgorithmEnum {



    SHA512("RSA", "SHA512", 1), SHA1("RSA", "SHA1", 1), SHA384("RSA", "SHA384", 1);



    private String keyAlgorithm;

    private String hashAlgorithm;

    private Integer key;



    private AlgorithmEnum(String keyAlgorithm, String hashAlgorithm, Integer key) {

        this.keyAlgorithm = keyAlgorithm;

        this.hashAlgorithm = hashAlgorithm;

        this.key = key;

    }



    public String getKeyAlgorithm() {

        return keyAlgorithm;

    }



    public void setKeyAlgorithm(String keyAlgorithm) {

        this.keyAlgorithm = keyAlgorithm;

    }



    public String getHashAlgorithm() {

        return hashAlgorithm;

    }



    public void setHashAlgorithm(String hashAlgorithm) {

        this.hashAlgorithm = hashAlgorithm;

    }



    public Integer getKey() {

        return key;

    }



    public void setKey(Integer key) {

        this.key = key;

    }

}

I need to have method something like below which takes input as string and returns Enum

public AlgorithmEnum getAlgorithm(String algorithm){

        //returns AlgorithmEnum object

    }

I would call above method by passing "SHA512withRSA" as input for getAlgorithm method.

I need help in implementing the getAlgorithm method.

You can have something like:

public static AlgorithmEnum getAlgorithm(final String algorithm)

        throws IllegalArgumentException

    {

        for (final AlgorithmEnum algorithmEnum : AlgorithmEnum.values())

        {

            if (algorithm.equalsIgnoreCase(String.format("%swith%s", algorithmEnum.getHashAlgorithm(), algorithmEnum.getKeyAlgorithm())))

            {

                return algorithmEnum;

            }

        }

        throw new IllegalArgumentException("Unknown algorithm: " + algorithm);

    }

However, I will not suggest to use this approach. Instead use 2 different arguments instead of a single String.

Assuming all string values passed to your method getAlgorithm() end with withRSA you could use the following to fetch the enum values :

public AlgorithmEnum getAlgorithm(String algorithm) {

    return AlgorithmEnum.valueOf(algorithm.substring(0, algorithm.indexOf("withRSA")));

}

You can check if the given String contains a value that matches one of the enum attributes with some if statements:

public AlgorithmEnum getAlgorithm(String algorithm) {

    if (algorithm.contains("SHA1")) {

        return SHA1;

    } else if (algorithm.contains("SHA512")) {

        return SHA512;

    } else if (algorithm.contains("SHA384")) {

        return SHA384;

    } else {

        return null;

    }

}

Please note that this will match Strings like "SHA512withoutRSA", too...

Maybe a method like

public AlgorithmEnum getAlgorithm(String keyAlgorithm, String hashAlgorithm)

would be better. However, you would have to provide two parameters then.

I'm leaving you an example of how I did on similar cases, you can easily adapt it to your needs:

private static Map<Integer, YourEnum> valuesById = new HashMap<>();

private static Map<String, YourEnum> valuesByCode = new HashMap<>();



    static {

        Arrays.stream(YourEnum.values()).forEach(value -> valuesById.put(value.reasonId, value));

        Arrays.stream(YourEnum.values()).forEach(value -> valuesByCode.put(value.reasonCode, value));

    }





    public static YourEnum getByReasonId(int endReason) {

        return valuesById.get(endReason);

    }