public long getLong(String attrName) {
        BigDecimal bd = getNumber(attrName);
        if (bd == null)
            throw new NumberFormatException
                ("value of " + attrName + " is null");
        return bd.longValue();
    }
Returns the value of the specified attribute in the current item as an
<code>long</code>.

@see #isNull(String) #isNull(String) to check if the attribute value is
     null.
@see #isPresent(String) #isPresent(String) to check if the attribute
     value is present.

@throws NumberFormatException
            if the attribute value is null or not a valid representation
            of a {@code BigDecimal}.
aws-java-sdk-dynamodb/src/main/java/com/amazonaws/services/dynamodbv2/document/Item.java