EDIT

package eu.etaxonomy.taxeditor.handler;

import java.util.ArrayList;

import java.util.List;

import java.util.UUID;

import org.eclipse.core.commands.AbstractParameterValueConverter;

import org.eclipse.core.commands.ParameterValueConversionException;

/**

 * Converts either a single {@link UUID} or a list of UUIDSs to a string representation

 * and vica versa.

 *

 * @author pplitzner

 * @date Sep 15, 2015

 *

 */

public class UuidsParameterTypeConverter extends AbstractParameterValueConverter {

    private static final String SEPARATOR = ",";

    public UuidsParameterTypeConverter() {

    }

    @Override

    public Object convertToObject(String parameterValue) throws ParameterValueConversionException {

        if(parameterValue.endsWith(SEPARATOR)){

            List<UUID> uuids = new ArrayList<UUID>();

            String[] split = parameterValue.split(SEPARATOR);

            for (String string : split) {

                uuids.add(UUID.fromString(string));

            }

            return uuids;

        }

        else{

            return UUID.fromString(parameterValue);

        }

    }

    @Override

    public String convertToString(Object parameterValue) throws ParameterValueConversionException {

        if(parameterValue instanceof List){

            List list = (List)parameterValue;

            String stringList = "";

            for (Object object : list) {

                stringList += parameterValue.toString()+SEPARATOR;

            }

        }

        else if(parameterValue instanceof UUID){

            return parameterValue.toString();

        }

        else{

            throw new ParameterValueConversionException("Parameter is of wrong type: "+parameterValue.getClass().toString());

        }

        return null;

    }

}