That looks pretty cool.  Do you think you could add a Wiki page for this.  It 
would be easier to find there if someone needed enums in their project.

Thanks, 
Nathan

----- Original Message -----
From: "celeraman+" <[EMAIL PROTECTED]>
To: [email protected]
Sent: Monday, June 4, 2007 7:01:20 AM (GMT-0800) America/Los_Angeles
Subject: [appfuse-user] Java 5 Enums Persistence :: How-to


If you need to map Java 5 Enums to Hibernate using JPA annotations this is
you are looking for.


First, a sample POJO from AppFuse Persistence tutorial to demo how to use
the annotations.

--- cut here -------------------------------------
package org.appfuse.tutorial.model;

@Entity
@Table(name="t_person")
public class Person extends BaseObject {

   // Enumerations ---------------------------
     public enum Sex{

      MALE(1),
      FEMALE(2);

      private int value;

      Sex(int value) {
          this.value = value;
      }

      // the identifierMethod
      public int toInt() {
        return value;
      }

       // the valueOfMethod
       public  static Sex fromInt(int value) {    
           switch(value) {
               case 1: return MALE;
               case 2: return FEMALE;
               default:
                       return UNKNOW;
           }
      }
     
      public String toString() {
        switch(this) {
          case MALE:
              return "Male";
          case FEMALE:
              return "Female";
        }
      }
    }



    // Attributes ---------------------------

    @Id
    @Column(name= "person_id")
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;

    @Column(name="person_firstname", length = 50, nullable = false)
    private String firstName;

    @Column(name="person_lastname", length = 50, nullable = false)
    private String lastName;
    
    @Column(name= "person_sex", columnDefinition="integer", nullable = true)
    @Type(type = "org.appfuse.tutorial.commons.hibernate.GenericEnumUserType
",
        parameters = {
                @Parameter(
                    name  = "enumClass",                      
                    value = "org.appfuse.tutorial.model.Person$Sex"),
                @Parameter(
                    name  = "identifierMethod",
                    value = "toInt"),
                @Parameter(
                    name  = "valueOfMethod",
                    value = "fromInt")
                }
    )
    private IdentidadeDocTipos tipo;


    /*
    Getters and Setters ...
    */
}

2) Now, use the "Flexible solution - working version" (thanks to Martin
Kersten)
from the article Java 5 EnumUserType, see http://www.hibernate.org/272.html
to map the Sex attribute.

--- cut here -------------------------------------
package org.appfuse.tutorial.commons.hibernate;

import java.io.Serializable;
import java.lang.reflect.Method;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Properties;

import org.hibernate.HibernateException;
import org.hibernate.type.NullableType;
import org.hibernate.type.TypeFactory;
import org.hibernate.usertype.ParameterizedType;
import org.hibernate.usertype.UserType ;

/**
 * Implements a generic enum user type identified / represented by a single
identifier / column.
 * <p><ul>
 *    <li>The enum type being represented by the certain user type must be
set
 *        by using the 'enumClass' property.</li>
 *    <li>The identifier representing a enum value is retrieved by the
identifierMethod.
 *        The name of the identifier method can be specified by the
 *        'identifierMethod' property and by default the name() method is
used.</li>
 *    <li>The identifier type is automatically determined by
 *        the return-type of the identifierMethod.</li>
 *    <li>The valueOfMethod is the name of the static factory method
returning
 *        the enumeration object being represented by the given indentifier.
 *        The valueOfMethod's name can be specified by setting the
'valueOfMethod'
 *        property. The default valueOfMethod's name is 'valueOf'.</li>
 * </p>
 * <p>
 * Example of an enum type represented by an int value:
 * <code>
 * public enum SimpleNumber {
 *   Unknown(-1), Zero(0), One(1), Two(2), Three(3);
 *   int value;
 *   protected SimpleNumber(int value) {
 *       this.value = value;
 *       }
 *
 *   public int toInt() { return value; }
 *   public SimpleNumber fromInt(int value) {
 *         switch(value) {
 *          case 0: return Zero;
 *         case 1: return One;
 *         case 2: return Two;
 *         case 3: return Three;
 *         default:
 *                 return Unknown;
 *     }
 *   }
 * }
 * </code>
 * <p>
 * The Mapping would look like this:
 * <code>
 *    <typedef name="SimpleNumber" class="GenericEnumUserType">
 *        SimpleNumber
 *        toInt
 *        fromInt
 *    </typedef>
 *    <class ...>
 *      ...
 *     <property name="number" column="number" type="SimpleNumber"/>
 *    </class>
 * </code>
 *
 * @author Martin Kersten
 * @since 05.05.2005
 */
public class GenericEnumUserType implements UserType, ParameterizedType {
    private static final String DEFAULT_IDENTIFIER_METHOD_NAME = "name";
    private static final String DEFAULT_VALUE_OF_METHOD_NAME = "valueOf";

    private Class<? extends Enum> enumClass;
    private Class<?> identifierType;
    private Method identifierMethod;
    private Method valueOfMethod;
    private NullableType type;
    private int[] sqlTypes;

    public void setParameterValues(Properties parameters) {
        String enumClassName = parameters.getProperty ("enumClass");
        try {
            enumClass = Class.forName(enumClassName).asSubclass(Enum.class);
            System.out.println(">>>enumClass: " + enumClass.toString());
        } catch (ClassNotFoundException cfne) {
            throw new HibernateException("Enum class not found", cfne);
        }

        String identifierMethodName =
parameters.getProperty("identifierMethod", DEFAULT_IDENTIFIER_METHOD_NAME);

        try {
            identifierMethod = enumClass.getMethod(identifierMethodName, new
Class[0]);
            identifierType = identifierMethod.getReturnType();
            // XXX
            System.out.println (">>>identifierMethod: " +
identifierMethod.toString());
            System.out.println(">>>identifierType: " +
identifierType.toString());
        } catch (Exception e) {
            throw new HibernateException("Failed to obtain identifier
method", e);
        }

        type = (NullableType) TypeFactory.basic(identifierType.getName());

        if (type == null)
            throw new HibernateException("Unsupported identifier type " +
identifierType.getName ());

        sqlTypes = new int[] { type.sqlType() };

        String valueOfMethodName = parameters.getProperty("valueOfMethod",
DEFAULT_VALUE_OF_METHOD_NAME);
        System.out.println(">>>valueOfMethodName: " + valueOfMethodName);

        try {
            valueOfMethod = enumClass.getMethod(valueOfMethodName, new
Class[] { identifierType });
            System.out.println(">>>valueOfMethod: " + valueOfMethod.toString
());
        } catch (Exception e) {
            throw new HibernateException("Failed to obtain valueOf method",
e);
        }
    }

    public Class returnedClass() {
        return enumClass;
    }

    public Object nullSafeGet(ResultSet rs, String[] names, Object owner)
throws HibernateException, SQLException {
        Object identifier = type.get(rs, names[0]);
        if (identifier == null) {
            return null;
        }

        try {
            return valueOfMethod.invoke(enumClass, new Object[] { identifier
});
        } catch (Exception e) {
            throw new HibernateException("Exception while invoking valueOf
method '" + valueOfMethod.getName() + "' of " +
                    "enumeration class '" + enumClass + "'", e);
        }
    }

    public void nullSafeSet(PreparedStatement st, Object value, int index)
throws HibernateException, SQLException {
        try {
            if (value == null) {
                st.setNull(index, type.sqlType());
            } else {
                Object identifier = identifierMethod.invoke(value, new
Object[0]);
                type.set(st, identifier, index);
            }
        } catch (Exception e) {
            throw new HibernateException("Exception while invoking
identifierMethod '" + identifierMethod.getName () + "' of " +
                    "enumeration class '" + enumClass + "'", e);
        }
    }

    public int[] sqlTypes() {
        return sqlTypes;
    }

    public Object assemble(Serializable cached, Object owner) throws
HibernateException {
        return cached;
    }

    public Object deepCopy(Object value) throws HibernateException {
        return value;
    }

    public Serializable disassemble(Object value) throws HibernateException
{
        return (Serializable) value;
    }

    public boolean equals(Object x, Object y) throws HibernateException {
        return x == y;
    }

    public int hashCode(Object x) throws HibernateException {
        return x.hashCode();
    }

    public boolean isMutable() {
        return false;
    }

    public Object replace(Object original, Object target, Object owner)
throws HibernateException {
        return original;
    }
}
--- cut here -------------------------------------

So, that's it! Maybe this helps someone!

Thank you all AppFusers!
--
celeraman +
-- 
View this message in context: 
http://www.nabble.com/Java-5-Enums-Persistence-%3A%3A-How-to-tf3865408s2369.html#a10950327
Sent from the AppFuse - User mailing list archive at Nabble.com.

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