Reason to create an interface when extend blc entity

[denis]

Hi,
We would like to know for what reason we must create an interface for our custom entities when we extends a broadleaf entity.

In your documention there is this example :

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public class HotSauceImpl extends ProductImpl implements HotSauce

So we have create an interface for each of our custom entities that extends a BLC entity but all of these interfaces are empty and so we wonder where they are useful ?

We tried to extend a BLC entity without create an interface for our custom entity and it works too :

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public class HotSauceImpl extends ProductImpl

Thanks for your answer

[phillipuniverse]

In your code it's not really necessary to have an interface as well. Nothing about that prevents BLC from operating correctly.

The only exception was something that we found when we were there with you all. SkuImpl has some code that depends on your extended SkuImpl having an interface declared for it if you want to use the DynamicSkuPricingService when proxying the Sku (look at getRetailPrice() and getSalePrice() in SkuImpl; there is a line that uses getClass().getInterfaces()). I believe it will end up throwing a ClassCastException if this is not the case.

The other caveat is that in order for your entities to work in the admin datasources, they must implement the Serializable interface.

[denis]

Thanks for your answer.

So we keep the interface for MySkuImpl but we can delete them for the other entities.

[phillipuniverse]

Yup, let me know if you run into any problems with this. If you do, we would like to know about it. Thanks!

[pccfrmvns]

Hi,

I am also trying to extend an BL Sku entity. I've created an interface(MySku) and extended the SkuImpl in MySkuImpl class and implemented MySku.

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public interface MySku {

   public void setRentalPrices(Map<Integer, BigDecimal> rentalPrices);
   
   public Map<Integer, BigDecimal> getRentalPrices();
}

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@Entity
@Inheritance(strategy = InheritanceType.JOINED)
@Table(name="MY_SKU")
@Cache(usage = CacheConcurrencyStrategy.READ_WRITE, region="blStandardElements")
public class MySkuImpl extends SkuImpl implements MySku{

   /**
    *
    */
   private static final long serialVersionUID = -518974372567977433L;
   @Transient
   protected static final Log LOG = LogFactory.getLog(TbrSkuImpl.class);
   
   @Resource(name="myRentalEngine")
   @Transient
   protected IRentalEngine rentalEngine;
   
   @Transient
   protected Map<Integer, BigDecimal> rentalPrices = new HashMap<Integer, BigDecimal>();
   

   @Override
   public void setRetailPrice(Money retailPrice) {
      super.setRetailPrice(retailPrice);
      
      //Set Rental price after setting Retail Price
      try {
         rentalPrices = rentalEngine.calculateAllRentals(retailPrice.getAmount());
      } catch (RentalServiceException e) {
         LOG.warn("Error in rental price calculation for retail price: "+retailPrice.getAmount()+" "+e.getMessage());
         //e.printStackTrace();
      }
   }
   
   public void setRentalPrices(Map<Integer, BigDecimal> rentalPrices) {
      this.rentalPrices = rentalPrices;
   }
   
   public Map<Integer, BigDecimal> getRentalPrices(){
      return this.rentalPrices;
   }
   
}


I've added this implementation class in persistence.xml and overrided Sku entity by in application context as

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<bean id="org.broadleafcommerce.core.catalog.domain.Sku" class="com.mycompany.core.catalog.domain.MySkuImpl" scope="prototype"/>

Now I am trying to access the rentalPrices field by Spring EL expression. in listProducItem.html. I get exception as below

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Field or property 'rentalPrices' cannot be found on object of type 'org.broadleafcommerce.core.catalog.domain.SkuImpl'

Please help.

[denis]

Hi, I don't know if it can resolve your problem but first of all your class MySku should extends the interface Sku :

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public interface MySku extends Sku {

   public void setRentalPrices(Map<Integer, BigDecimal> rentalPrices);
   
   public Map<Integer, BigDecimal> getRentalPrices();
}


[phillipuniverse]

How did you add the Sku to begin with? Via the admin? There might be a problem in the admin when instantiating Skus; it's possible that we don't instantiate the correct subclass. I assume there is no corresponding entry in your MY_SKU table?

[phillipuniverse]

FYI, the second discussion is actively being continued at viewtopic.php?f=11&t=1625