Customizing shipping charges

In some cases you may need to customize your shipping calculation. For example, if an item and its parent product are under different categories and each category has a different shipping calculation code attached, then both shipping calculation codes will be picked up by the runtime, and the final result will be cumulative. To avoid this, you can customize the code, by overriding CalculationCodeCombineCmdImpl.getIndirectlyAttachedCodes().

1. Create a task command that extends CalculationCodeCombineCmd. For example,

   public interface EGShippingCalculationCodeCombineCmd extends 
   CalculationCodeCombineCmd { 
   public static final String defaultCommandClassName = 
   "com.example.commerce.order.calculation.EGShippingCalculationCodeCombineCmd
   
   Impl"; 
   } 
   

2. Create an implementation of the task command that extends CalculationCodeCombineCmdImpl. For example,

   EGShippingCalculationCodeCombineCmdImpl extends 
   CalculationCodeCombineCmdImpl implements 
   EGShippingCalculationCodeCombineCmd { 
   } 
   

3. Extend the default behavior of getIndirectlyAttachedCodes(Item) to filter the extraneous shipping calculation codes. For example,

   protected CalculationCodeAccessBean[]
   getIndirectlyAttachedCodes(Item 
   iItem) { 
   CalculationCodeAccessBean[] abCodes = 
   super.getIndirectlyAttachedCodes(iItem); 
   //if the array contains both the product and item level shipping 
   calculation codes, get rid of the product level one 
   return abCodes; 
   } 
   

4. Register the task command as a calculation method in the CALMETHOD table. For example,

   INSERT INTO CALMETHOD VALUES (<some unique ID>, -1, -2, 
   'com.example.commerce.order.calculation.EGShippingCalculationCodeCombineCmd
   
   ', 'EG custom CalculationCodeCombine for shipping', 1, 
   'EGShippingCalculationCodeCombine') 
   

5. Set the calculation method as the CalculationCodeCombine calculation method for shipping:

   UPDATE STENCALUSG SET ACTCC_CALMETHOD_ID=<calculation method
   ID> WHERE 
   STOREENT_ID IN (<store ID>, -1) AND CALUSAGE_ID=-2
   

Since CalculationHelper.getProductAndItemIds(nCatalogEntryId) cannot be customized, it is not recommended that you patch it to get the desired behavior.

Related concepts

Shipping

Related tasks

Change shipping codes
Deleting shipping codes
Activating and deactivating shipping codes
Define shipping charges
Set up shipping

Related reference

Example of shipping calculations