@SuppressWarnings("unchecked")
        public <S,T> DynamoDBTypeConverter<S,T> get(Class<S> sourceType, Class<T> targetType) {
            for (final Entry<Key<?,?>,DynamoDBTypeConverter<?,?>> entry : entrySet()) {
                if (entry.getKey().isAssignableFrom(sourceType, targetType)) {
                    return (DynamoDBTypeConverter<S,T>)entry.getValue();
                }
            }
            return null;
        }
Map of source and target pairs to the converter.
aws-java-sdk-dynamodb/src/main/java/com/amazonaws/services/dynamodbv2/datamodeling/DynamoDBTypeConverterFactory.java