package org.cyclick.commons.hibernate.search.bridge;

import java.util.Collection;

import org.hibernate.search.bridge.StringBridge;

/**
 * Transform a collection of enum constants into a string representation.
 * 
 * <p>The result if a string containing the names of every enum constants separated by a white space.</p> 
 * 
 * <p>"_" are removed from the enum constants name.</p>
 * 
 * @author Thomas Vanstals
 * @since 2.2.0 
 */
public class CollectionOfEnumsBridge implements StringBridge {

   private static final String UNDERSCORE = "_";

   private static final String WHITE_SPACE = " ";
   
   private static final String EMPTY_STRING = "";

   @Override
   public String objectToString(Object object) {
      String result = null;
      if (object != null && object instanceof Collection<?>) {
         StringBuilder sb = new StringBuilder();
         Collection<?> items = (Collection<?>) object;
         for (Object item : items) {
            if (item != null && item.getClass().isEnum()) {
               if (sb.length() > 0) {
                  sb.append(WHITE_SPACE);
               }
               Enum<?> e = (Enum<?>) item;
               sb.append(e.name().replace(UNDERSCORE, EMPTY_STRING));
            }
         }
         result = sb.toString();
      }
      return result;
   }

}