public static HttpMethodName fromValue(String value) {
        if (StringUtils.isNullOrEmpty(value)) {
            return null;
        }

        final String upperCaseValue = StringUtils.upperCase(value);
        for (HttpMethodName httpMethodName : values()) {
            if (httpMethodName.name().equals(upperCaseValue)) {
                return httpMethodName;
            }
        }
        throw new IllegalArgumentException("Unsupported HTTP method name " + value);
    }
@param value Raw string representing value of enum
@return HttpMethodName enum or null if value is not present.
@throws IllegalArgumentException If value does not represent a known enum value.
aws-java-sdk-core/src/main/java/com/amazonaws/http/HttpMethodName.java