Customizing the promotion sequence builder

The following is a sample sequence builder. It is similar to the default sequence builder, except that it does not give priority to promotions for which a promotion code or coupon has been entered.

package com.ibm.commerce.marketing.promotion.runtime;

import java.util.Enumeration;
import java.util.Vector;

import org.w3c.dom.Node;

import com.ibm.commerce.copyright.IBMCopyright;
import com.ibm.commerce.marketing.promotion.Promotion;
import com.ibm.commerce.marketing.promotion.group.PromotionGroup;
import com.ibm.commerce.marketing.promotion.group.PromotionGroupKey;
import com.ibm.commerce.marketing.promotion.xml.DeXMLizationException;
import com.ibm.commerce.marketing.promotion.xml.XMLizationException;
import com.ibm.commerce.marketing.util.XMLHelper;

/**
 *A sequence builder for the promotion engine. The following rules are observed
 * 1. Promotions specified in a group that is defined earlier in the promotion
 *    invocation template are called before a promotion that is in a group defined
 *    later in the template.
 * 2. For promotions in the same group, when all else is equal, the one with a higher
 *    priority is invoked earlier than one that has a lower priority.
 *
 */
 
public class StaticSequenceBuilder implements PromotionExecutionSequenceBuilder {

   /**
    * IBM Copyright
    */
   public static final String COPYRIGHT= IBMCopyright.SHORT_COPYRIGHT;
        
        
   /**
    * Constructor.
    *
    */ 
   public StaticSequenceBuilder() {
      super();
   }

   /**
    * Compares the priority of two promotions
    * @param promo1
    * @param promo2
    * @param context the current promotion context
    * @return >;0 when promo1 has precedence over promo2, =0,
    * promo1 and promo2 have the same priority, <0, promo2
    * takes precedence over promo1
    */
   protected int comparePromotionPriority(
      Promotion promo1,
      Promotion promo2,
      PromotionContext context) {
           
         PromotionGroupKey key1 = promo1.getGroupKey();
         PromotionGroupKey key2 = promo2.getGroupKey();
           
         PromotionGroup groups[] = context.getGroups();
         for (int i= 0; i < groups.length; i++) {
            if (groups[i].getKey().equals(key1)
            && (!groups[i].getKey().equals(key2))) {
               return 1;
            }
            if (groups[i].getKey().equals(key2)
               && (!groups[i].getKey().equals(key1))) {
                  return -1;
               }
            }
           
            return promo1.getPriority().compareTo(promo2.getPriority());
         }
        
         /**
          * @see com.ibm.commerce.marketing.promotion.runtime.
          * PromotionExecutionSequenceBuilder#buildSequence(
          * com.ibm.commerce.marketing.promotion.runtime.PromotionContext)
          */
         public Vector buildSequence(PromotionContext context) {
            // calculate the sequence in which promotions will be evaluated
            Vector sequence = new Vector();
            Enumeration promos = context.listAllPromotions();
            while (promos.hasMoreElements()) {
               Promotion promo = (Promotion) promos.nextElement();
               boolean inserted = false;
               for (int i = 0; i < sequence.size(); i++) {
                  if (comparePromotionPriority(promo,
                     (Promotion) sequence.elementAt(i),
                     context) > 0) {
                        sequence.insertElementAt(promo, i);
                        inserted = true;
                        break;
                  }
               }
               if (!inserted) {
                  sequence.addElement(promo);
               }
            }
            return sequence;
         }
         
         /**
          * @see com.ibm.commerce.marketing.promotion.xml.XMLizable#toXML()
          */
         public String toXML() throws XMLizationException {
            StringBuffer buffer = new StringBuffer();
            buffer
               .append("<PromotionExecutionSequenceBuilder impl=\"")
               .append(this.getClass().getName())
               .append("\"/>");
               
            return buffer.toString();
         }
         
         
         /**
          * @see com.ibm.commerce.marketing.promotion.xml
          * .XMLizable#fromXML(org.w3c.dom.Node)
          */
         public void fromXML(Node anXMLNode) throws DeXMLizationException {
            try {
               if this.getClass()
                  != Class.forName(
                  XMLHelper.getAttributeValue(anXMLNode,"impl"))) {
                     throw new DeXMLizationException("Wrong implementation");
                  }
               } catch (DeXMLizationException e) {
                  throw e;
               } catch (Throwable e) {
                  throw new DeXMLizationException(e.toString());
               }
            }
            
         }
      }