CODEWITHSUNDEEP
javagenericsreflection
Ramakrishna
Ramakrishna

Reputation: 1200

get generic type from object list java

I had custom converter for dozer framework

constom converter called for generic type list source and generic type list destination 

public class ListCommonCustomConverter implements ConfigurableCustomConverter{
  public Object convert(Object destination, Object source, Class<?> destinationClass, Class<?> sourceClass) {
    log.info("Inside CommonCustomConverter :: convert");
    // Need to fine generic type of list
    return null;
  }
}

Eg: if List<Person> passed as destination for converter i need to get Person class from destination object inside converter method.

Thank in Advance.

Upvotes: 3

Views: 1847

Answers (1)

Andrey Chaschev
Andrey Chaschev

Reputation: 16476

You could get type info from a generic type by calling getClass().getGenericInterfaces() if your class was declared like:

public class ListCommonCustomConverter implements ConfigurableCustomConverter<Person>

But since this converter is not parameterized, you could do a trick:

public interface CustomConverterWithTypeInfo<T> extends ConfigurableCustomConverter{
}


public class ListCommonCustomConverter implements CustomConverterWithTypeInfo<Person>{
    public Object convert(Object destination, Object source, Class<?> destinationClass, Class<?> sourceClass) {
        Class<?> myClass = (Class)((ParameterizedType)getClass().getGenericInterfaces()[0]).getActualTypeArguments()[0];
        //...
    }
}

Or you could simply do:

List<?> list = (List)destination;
if(!list.isEmpty()){
     Class<?> myClass = list.get(0).getClass();
}

Upvotes: 1

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