public abstract class AbstractEnum implements Serializable {
   
   private String id;
   private transient String value;

   /**
    * @param id
    * @param value
    */
   protected AbstractEnum(String id, String value) {
      this.id = id;
      this.value = value;
   }
   
    /**
    * @return Returns the id.
    */
   public String getId() {
      return id;
   }

   /**
    * @return Returns the value.
    */
   public String getValue() {
      return value;
   }
   
    public boolean equals(Object other) {
        return this == other;
    }
   
    public int hashCode() {
        return System.identityHashCode(id);
    }
   
    public String toString() {
        return value;
    }

}

public class NumberEnum extends AbstractEnum {
   
    public static final String ONE = "1";
    public static final String TWO = "2";
    
    public static final NumberEnum ONE_LITERAL = new NumberEnum(ONE, "One");
    public static final NumberEnum TWO_LITERAL = new NumberEnum(TWO, "Two");

   /**
    * @param id
    * @param value
    */
   private NumberEnum(String id, String value) {
      super(id, value);
   }
   
   public static NumberEnum fromString(String id) {
      if (ONE.equals(id)) {
         return ONE_LITERAL;
      } else if (TWO.equals(id)) {
         return TWO_LITERAL;
      } else {
         return null;
      }
   }

   private Object resolveObject() {
      return fromString(getId());
   }

}

public class EnumUserType implements EnhancedUserType, ParameterizedType {

   private Class enumClass;
   private Method fromString;

   /* (non-Javadoc)
    * @see org.hibernate.usertype.EnhancedUserType#objectToSQLString(java.lang.Object)
    */
   public String objectToSQLString(Object value) {
          return '\'' + idOf(value) + '\'';
   }

   /* (non-Javadoc)
    * @see org.hibernate.usertype.EnhancedUserType#toXMLString(java.lang.Object)
    */
   public String toXMLString(Object value) {
      return idOf(value);
   }

   /* (non-Javadoc)
    * @see org.hibernate.usertype.EnhancedUserType#fromXMLString(java.lang.String)
    */
   public Object fromXMLString(String xmlValue) {
      return valueOf(xmlValue);
   }

   /* (non-Javadoc)
    * @see org.hibernate.usertype.UserType#sqlTypes()
    */
   public int[] sqlTypes() {
      return new int[] { Types.VARCHAR };
   }

   /* (non-Javadoc)
    * @see org.hibernate.usertype.UserType#returnedClass()
    */
   public Class returnedClass() {
      return enumClass;
   }

   /* (non-Javadoc)
    * @see org.hibernate.usertype.UserType#equals(java.lang.Object, java.lang.Object)
    */
   public boolean equals(Object x, Object y) throws HibernateException {
      return x == y;
   }

   /* (non-Javadoc)
    * @see org.hibernate.usertype.UserType#hashCode(java.lang.Object)
    */
   public int hashCode(Object x) throws HibernateException {
      return x.hashCode();
   }

   /* (non-Javadoc)
    * @see org.hibernate.usertype.UserType#nullSafeGet(java.sql.ResultSet, java.lang.String[], java.lang.Object)
    */
   public Object nullSafeGet(ResultSet rs, String[] names, Object owner)
         throws HibernateException, SQLException {
        String name = rs.getString( names[0] );
        return rs.wasNull() ? null : valueOf(name);
   }

   /* (non-Javadoc)
    * @see org.hibernate.usertype.UserType#nullSafeSet(java.sql.PreparedStatement, java.lang.Object, int)
    */
   public void nullSafeSet(PreparedStatement st, Object value, int index)
         throws HibernateException, SQLException {
      if (value == null) {
         st.setNull(index, Types.VARCHAR);
      } else {
         st.setString(index, idOf(value));
      }
   }

   /* (non-Javadoc)
    * @see org.hibernate.usertype.UserType#deepCopy(java.lang.Object)
    */
   public Object deepCopy(Object value) throws HibernateException {
      return value;
   }

   /* (non-Javadoc)
    * @see org.hibernate.usertype.UserType#isMutable()
    */
   public boolean isMutable() {
      return false;
   }

   /* (non-Javadoc)
    * @see org.hibernate.usertype.UserType#disassemble(java.lang.Object)
    */
   public Serializable disassemble(Object value) throws HibernateException {
      return (Serializable)value;
   }

   /* (non-Javadoc)
    * @see org.hibernate.usertype.UserType#assemble(java.io.Serializable, java.lang.Object)
    */
   public Object assemble(Serializable cached, Object owner)
         throws HibernateException {
      return cached;
   }

   /* (non-Javadoc)
    * @see org.hibernate.usertype.UserType#replace(java.lang.Object, java.lang.Object, java.lang.Object)
    */
   public Object replace(Object original, Object target, Object owner)
         throws HibernateException {
      return original;
   }

   /* (non-Javadoc)
    * @see org.hibernate.usertype.ParameterizedType#setParameterValues(java.util.Properties)
    */
   public void setParameterValues(Properties parameters) {
        String enumClassName = parameters.getProperty("enumClassName");
        try {
            enumClass = Class.forName(enumClassName);
         fromString = enumClass.getMethod("fromString", new Class[] {String.class});
         if (!AbstractEnum.class.isAssignableFrom(enumClass)) {
               throw new HibernateException("Enum class <" + enumClassName + "> does not extend AbstractEnum class.");
         }
        } catch (ClassNotFoundException cnfe) {
            throw new HibernateException("Enum class <" + enumClassName + "> not found: ", cnfe);
      } catch (NoSuchMethodException nsme) {
            throw new HibernateException("Enum class <" + enumClassName + "> does not contain formString method: ", nsme);
        }
        try {
           enumClass.getDeclaredMethod("resolveObject", new Class[0]);
      } catch (NoSuchMethodException nsme) {
            throw new HibernateException("Enum class <" + enumClassName + "> does not contain resolveObject method: ");
        }
   }
   
   private String idOf(Object value) {
      return ((AbstractEnum)value).getId();
   }
   
   private Object valueOf(String id) {
      try {
         return fromString.invoke(null, new Object[] {id});
      } catch (IllegalAccessException e) {
            throw new HibernateException("Illegal access to method fromString from class <" + enumClass.getName() + ">: ", e);
      } catch (InvocationTargetException e) {
            throw new HibernateException("Could not invoke method fromString from class <" + enumClass.getName() + ">: ", e);
      }
   }

}

<?xml version="1.0" encoding="ASCII"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="com.foo.bar.test">
  <class name="TestEnum" table="testEnum">
    <id column="id" name="id" type="long">
      <generator class="native"/>
    </id>
    <property column="test_enum" length="1" name="testEnum">
      <type name="com.previnet.hibernate.usertypes.EnumUserType">
        <param name="enumClassName">com.foo.bar.test.NumberEnum</param>
      </type>
    </property>
  </class>
</hibernate-mapping>

public class TestEnum  implements java.io.Serializable {

    // Fields   

     private Long id;
     private NumberEnum testEnum;


    // Constructors

    /** default constructor */
    public TestEnum() {
    }
   
    /** constructor with id */
    public TestEnum(Long id) {
        this.id = id;
    }
   
   
   

    // Property accessors

    /**
     *
     */
    public Long getId() {
        return this.id;
    }
   
    public void setId(Long id) {
        this.id = id;
    }

    /**
     *
     */
    public NumberEnum getTestEnum() {
        return this.testEnum;
    }
   
    public void setTestEnum(NumberEnum testEnum) {
        this.testEnum = testEnum;
    }



}