Re: Variable not initialized in the open() method of RichMapFunction

[Dong iL, Kim]

is open method signature right? or typo?

void open(Configuration parameters) throws Exception;

On Sat, Jul 23, 2016 at 12:09 AM, Stephan Ewen <se...@apache.org> wrote:

> I think you overrode the open method with the wrong signature. The right
> signature would be "open(Configuration cfg) {...}". You probably overlooked
> this because you missed the "@Override" annotation.
>
> On Fri, Jul 22, 2016 at 4:49 PM, Yassin Marzouki <yassmar...@gmail.com>
> wrote:
>
>> Hi everyone,
>>
>> I want to convert a stream of json strings to POJOs using Jackson, so I
>> did the following:
>>
>> .map(new RichMapFunction<String, Request>() {
>>
>>     private ObjectMapper objectMapper;
>>
>>         public void open() {
>>             objectMapper = new ObjectMapper();
>>         }
>>
>>         @Override
>>              public Request map(String value) throws Exception {
>>                  return objectMapper.readValue(value, Request.class);
>>         }
>> })
>>
>> But this code gave me a NullPointerException because the objectMapper was
>> not initialized successfully.
>>
>> 1. Isn't the open() method supposed to be called before map() and
>> initialize objectMapper?
>> 2. I figured out that initializing objectMapper before the open() method
>> resolves the problem, and that it works also with a simple MapFunction. In
>> that case, is there an advantage for using a RichMapFunction?
>>
>> Best,
>> Yassine
>>
>
>


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