What is UserType.

Yashnoo · **Joined:** Wed Dec 17, 2003 4:24 am **Posts:** 188

Hi everyone:

I see the UserType in many document.It seems very important conception in Hibernate. The Hibernate document says it is better to use UserType than composite-id. But there is little introduce to the "UserType". Someone can tell me how to use the "UserType" or give me an example? An simple example of "UserType" . THks.

Teg · **Posted:** Mon Sep 13, 2004 4:04 am

This is an example UserType to map a BigInteger to DB, it uses only one column but you can write UserType mapped on many columns:

Code:

import net.sf.hibernate.UserType;
import java.sql.*;
import java.math.*;

public class BigIntegerType implements UserType {
    
    private static final int[] SQL_TYPES = {Types.VARCHAR};
    private static final int RADIX = 2;
    
    public int[] sqlTypes() {
        return SQL_TYPES;
    }
    
    public BigIntegerType() {
    }
    
    public boolean equals(Object x, Object y) throws net.sf.hibernate.HibernateException {
        if (x == y) return true;
        if (x == null || y == null) return false;
        return x.equals(y);
    }
    
    public Object deepCopy(Object obj) throws net.sf.hibernate.HibernateException {
        return obj;
    }
    
    public boolean isMutable() {
        return false;
    }
    
    public Object nullSafeGet(java.sql.ResultSet resultSet, String[] names, Object owner) throws net.sf.hibernate.HibernateException, java.sql.SQLException {
        if (resultSet.wasNull()) return null;
        String res = resultSet.getString(names[0]);
        return decode(res);
    }
    
    public void nullSafeSet(java.sql.PreparedStatement statement, Object value, int index) throws net.sf.hibernate.HibernateException, java.sql.SQLException {
        if (value == null) {
            statement.setNull(index, sqlTypes()[0]);
        } else {
            BigInteger number = (BigInteger)value;
            statement.setString(index, encode(number));
        }
    }
    
    public Class returnedClass() {
        return BigInteger.class;
    }
    
    public static String encode(BigInteger value) {
        return value.toString(RADIX);
    }
    
    public static BigInteger decode(String value) {
        return new BigInteger(value, RADIX);
    }
    
}

Then you can use your class as type value for properties for example:

Code:

    <class name="Product" table="PRODUCTS">
        <id name="id" column="ID" type="string" length="32">
            <generator class="uuid.hex"/>
        </id>
        
        <property name="name" column="NAME" type="string" length="256"/>
        <property name="veryLongNumericCode" column="CODE" type="BigIntegerType"/>
        
    </class>

Yashnoo · **Joined:** Wed Dec 17, 2003 4:24 am **Posts:** 188

Thank you for your reply.But there are some thing that I don't understand in your code , the following code:

Code:

public static String encode(BigInteger value) { 
        return value.toString(RADIX); 
    } 
    
    public static BigInteger decode(String value) { 
        return new BigInteger(value, RADIX); 
    } 
    

What does it mean? I don't know why need I have to implement these two methed. Could you give me an composite-id example ? I mean that how to write a composite-id (two primary key) if I implement it using UserType? Thks

ernst_pluess · **Posted:** Wed Sep 15, 2004 8:25 am

Type:

Code:

package ch.bedag.gba.cap.server.persistence.hibernate;

import java.io.Serializable;

import org.apache.commons.lang.builder.EqualsBuilder;
import org.apache.commons.lang.builder.HashCodeBuilder;
import org.apache.commons.lang.builder.ReflectionToStringBuilder;

public class CapiPK implements Serializable {

   private Long mySystemId = null;
   private Long myId = null;
   
   public CapiPK() {
       super();
   }
    public CapiPK(Long systemId, Long pid) {
        this();
        mySystemId = systemId;
        myId = pid;
    }
    public CapiPK(long systemId, long pid) {
        super();
        mySystemId = new Long(systemId);
        myId = new Long(pid);
    }
   public Long getId() {
        return myId;
    }
    public void setId(Long pid) {
        myId = pid;
    }
    public Long getSystemId() {
        return mySystemId;
    }
    public void setSystemId(Long systemId) {
        mySystemId = systemId;
    }
    
    public boolean equals(Object obj) {
        if (!(obj instanceof CapiPK)) return false;
        CapiPK pk = (CapiPK)obj;
        return new EqualsBuilder()
           .append(mySystemId, pk.mySystemId)
           .append(myId, pk.myId)
           .isEquals();
    }
    
    public int hashCode() {
        return new HashCodeBuilder()
           .append(mySystemId)
           .append(myId)
           .toHashCode();
    }
    
    public String toString() {
       return new ReflectionToStringBuilder(this).toString();
    }
}

CompositeUserType:
[code]package ch.bedag.gba.cap.server.persistence.hibernate;

import java.io.Serializable;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Types;

import net.sf.hibernate.CompositeUserType;
import net.sf.hibernate.Hibernate;
import net.sf.hibernate.HibernateException;
import net.sf.hibernate.engine.SessionImplementor;
import net.sf.hibernate.type.Type;
import ch.bedag.gba.server.persistence.PersistenceRuntimeException;

public class CapiPkType implements CompositeUserType {

private static final ch.bedag.gba.common.logging.CapiLogger LOG = ch.bedag.gba.common.logging.CapiLoggerFactory
.getLog(CapiPkType.class);

private static final String[] PROPERTY_NAMES = {"systemId", "id"};
private static final Type[] PROPERTY_TYPES = {Hibernate.LONG, Hibernate.LONG};

public String[] getPropertyNames() {
return PROPERTY_NAMES;
}

public Type[] getPropertyTypes() {
return PROPERTY_TYPES;
}

public Object getPropertyValue(Object component, int property) throws HibernateException {
CapiPK capiPk = (CapiPK)component;
switch (property) {
case 0:
return capiPk.getSystemId();
case 1:
return capiPk.getId();
default:
throw new PersistenceRuntimeException(property+" ist kein g