public EncryptionMaterials generateDataKey()

in src/main/java/software/amazon/encryption/s3/materials/KmsKeyring.java [112:150]
35 lines of code
4 McCabe index (conditional complexity)

        public EncryptionMaterials generateDataKey(EncryptionMaterials materials) {
            DataKeySpec dataKeySpec;
            if (!materials.algorithmSuite().dataKeyAlgorithm().equals("AES")) {
                throw new S3EncryptionClientException(String.format("The data key algorithm %s is not supported by AWS " + "KMS", materials.algorithmSuite().dataKeyAlgorithm()));
            }
            switch (materials.algorithmSuite().dataKeyLengthBits()) {
                case 128:
                    dataKeySpec = DataKeySpec.AES_128;
                    break;
                case 256:
                    dataKeySpec = DataKeySpec.AES_256;
                    break;
                default:
                    throw new S3EncryptionClientException(String.format("The data key length %d is not supported by " + "AWS KMS", materials.algorithmSuite().dataKeyLengthBits()));
            }

            GenerateDataKeyRequest request = GenerateDataKeyRequest.builder()
                    .keyId(_wrappingKeyId)
                    .keySpec(dataKeySpec)
                    .encryptionContext(materials.encryptionContext())
                    .overrideConfiguration(builder -> builder.addApiName(API_NAME))
                    .build();
            GenerateDataKeyResponse response = _kmsClient.generateDataKey(request);

            byte[] encryptedDataKeyCiphertext = response.ciphertextBlob().asByteArray();
            EncryptedDataKey encryptedDataKey = EncryptedDataKey.builder()
                    .keyProviderId(S3Keyring.KEY_PROVIDER_ID)
                    .keyProviderInfo(keyProviderInfo().getBytes(StandardCharsets.UTF_8))
                    .encryptedDataKey(Objects.requireNonNull(encryptedDataKeyCiphertext))
                    .build();

            List<EncryptedDataKey> encryptedDataKeys = new ArrayList<>(materials.encryptedDataKeys());
            encryptedDataKeys.add(encryptedDataKey);

            return materials.toBuilder()
                    .encryptedDataKeys(encryptedDataKeys)
                    .plaintextDataKey(response.plaintext().asByteArray())
                    .build();
        }