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From Giacomo Licari <giacomo.lic...@gmail.com>
Subject Re: Inheritance and FlatMap with custom POJO
Date Wed, 16 Sep 2015 13:38:28 GMT
Thank you Martin and Stephan for your help.
I tried directly to implement java.io.Serializable in Base class and it
worked perfectly!

Now I can develop more flexible and maintainable code. Thank you a lot guys.

Greetings,
Giacomo

On Wed, Sep 16, 2015 at 1:46 PM, Stephan Ewen <sewen@apache.org> wrote:

> Hi!
>
> Interesting case. We use plain Java Serialization to distribute UDFs, and
> perform additional "cleaning" of scopes, which may be causing the issue.
>
> Can you try the following to see if any of those resolves the problem?
>
> 1) On the environment, disable the closure cleaner (in the execution
> config).
>
> 2) Let the CullTimeBase class implement java.io.Serializable.
>
> Please let us know how it turns out!
>
> Greetings,
> Stephan
>
>
> On Wed, Sep 16, 2015 at 1:29 PM, Martin Junghanns <m.junghanns@mailbox.org
> > wrote:
>
>> Hi Giacomo,
>>
>> I ran into the same issue. Seems to be coupled to the serialization
>> mechanism of UDFs. I solved it by letting the base class implement the UDF
>> interface (e.g. FlatMapFunction) and in addition make it generic (which
>> should be necessary in your example).
>>
>> public [abstract] class CullTimeBase<IN, OUT> implements
>> FlatMapFunction<IN, OUT> {
>> // ...
>> }
>>
>> public class CullTimeRainFall extends CullTimeBase<RainFallPOJO,
>> RainFallPOJO> {
>> // ...
>> }
>>
>> This should work.
>>
>> Best,
>> Martin
>>
>>
>> On 16.09.2015 10:41, Giacomo Licari wrote:
>>
>> Hi guys,
>> I'm trying to create a base class which is inherited from classes
>> implementing FlatMap method on specific POJO types.
>>
>> It seems inheritance doesn't work, I can access this.PropertyName or
>> super.PropertyName from flatMap method but values are always null.
>>
>> Here the derived class, using RainfallPOJO:
>>
>> public class CullTimeRainfall extends CullTimeBase implements
>> FlatMapFunction<RainfallPOJO, RainfallPOJO> {
>>
>> public CullTimeRainfall(int num, int den, String time_data_name, String
>> start_time, String end_time, int interval, String time_unit){
>> super(num, den, time_data_name, start_time, end_time, interval,
>> time_unit);
>> }
>>
>> public void flatMap(RainfallPOJO obj, Collector<RainfallPOJO> coll)
>> throws Exception {
>> DateFormat formatter = new SimpleDateFormat("yyyy-MM-dd'T'hh:mm:ss.SSS");
>> try {
>>    Date time = formatter.parse( obj.getTime().replaceAll(
>> "([0-9\\-T]+:[0-9]{2}:[0-9.+]+):([0-9]{2})", "$1$2" ) );
>>        if(time.after(this.startTime) && time.before(this.endTime)){
>> coll.collect(obj);
>> }
>> } catch(Exception e){
>> e.printStackTrace();
>> }
>> }
>> }
>>
>> My Base class is:
>>
>> public class CullTimeBase {
>>
>>   protected int numerator;
>>     protected int denominator;
>>     protected String timeDataName;
>>     protected Date startTime;
>>     protected Date endTime;
>>     protected int interval;
>>     protected String timeUnit;
>> public CullTimeBase(int num, int den, String time_data_name, String
>> start_time, String end_time, int interv, String time_unit){
>> numerator = num;
>> denominator = den;
>> timeDataName = time_data_name;
>> interval = interv;
>> timeUnit = time_unit;
>> DateFormat formatter = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS");
>> try {
>> startTime = formatter.parse(start_time);
>> endTime = formatter.parse(end_time);
>> } catch (ParseException e) {
>> e.printStackTrace();
>> }
>> }
>>
>> It works only if I declare all variables and methods in only one class,
>> but so I should repeat the same properties in more classes. I would only
>> specialize each derived class with a custom flatMap method. which uses a
>> custom POJO type.
>>
>> Thanks a lot,
>> Giacomo
>>
>>
>>
>

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