package org.kuali.common.util.xml.jaxb.adapter;
   
   import java.util.List;
   
   import javax.xml.bind.annotation.adapters.XmlAdapter;
   
   import org.apache.commons.lang3.StringUtils;
   import org.kuali.common.util.Assert;
   import org.kuali.common.util.CollectionUtils;
  
  import com.google.common.collect.ImmutableList;
  
  /**
   * Trim each element from List&lt;String> to create the CSV when going from Object -> XML.<br>
   * Convert the CSV back into List&lt;String> when going from XML -> Object.<br>
   * The List&lt;String> returned when going from XML -> Object is immutable.</br>
   * 
   * @throws NullPointerException
   *             If the list is null or any strings in the list are null
   * @throws IllegalArgumentException
   *             If any strings in the list contain a comma
   */
  public class TrimmingCSVStringAdapter extends XmlAdapter<String, List<String>> {
  
  	private static final String DELIMITER = ",";
  
  	@Override
  	public final String marshal(List<String> strings) {
  		if (strings.size() == 0) {
  			return null;
  		}
  		StringBuilder sb = new StringBuilder();
  		for (int i = 0; i < strings.size(); i++) {
  			if (i != 0) {
  				sb.append(DELIMITER);
  			}
  			String trimmed = strings.get(i).trim();
  			Assert.isFalse(StringUtils.contains(trimmed, DELIMITER), "[" + trimmed + "] contains '" + DELIMITER + "'");
  			sb.append(trimmed);
  		}
  		return sb.toString();
  	}
  
  	@Override
  	public final List<String> unmarshal(String string) {
  		if (string == null) {
  			return ImmutableList.<String> of();
  		} else {
  			return ImmutableList.copyOf(CollectionUtils.getTrimmedListFromCSV(string));
  		}
  	}
  
  }