[Hibernate-issues] [Hibernate-JIRA] Commented: (HB-249) CustomType for mapping classes onto Integers for use with <any>

[<leg...@at...>]

The following comment has been added to this issue:

     Author: Dhananjay Nene
    Created: Tue, 12 Aug 2003 3:05 AM
       Body:
Forgot to add one more utility class - as follows :
<pre>
class ClassToIntValue
{
	private Integer intVal;
	private Class clazz;
	
	public ClassToIntValue(Integer intVal, Class clazz)
	{
		this.intVal = intVal;
		this.clazz = clazz;
	}
	
	public Integer getIntVal()
	{
		return intVal;
	}
	
	public Class getClazz()
	{
		return clazz;
	}
}
</pre>
---------------------------------------------------------------------
View the issue:

  http://opensource.atlassian.com/projects/hibernate/secure/ViewIssue.jspa?key=HB-249


Here is an overview of the issue:
---------------------------------------------------------------------
        Key: HB-249
    Summary: CustomType for  mapping classes onto Integers for use with <any>
       Type: Patch

     Status: Unassigned
   Priority: Minor

    Project: Hibernate2

   Assignee: 
   Reporter: Dhananjay Nene

    Created: Tue, 12 Aug 2003 3:03 AM
    Updated: Tue, 12 Aug 2003 3:03 AM
Environment: Not applicable

Description:
The default mapping mechanism for <any> mapping is the class name. This custom type allows for creating integer values for each class, and mapping the classes onto the integer values. Thus the table needs to have a integer column and a column corresponding to the primary key of the other table. 

Using this class requires creating a derived class as suggested below.
Sample mapping will be as follows :

Scenario : An invoice table stores a reference to a Customer. Customer is an abstract base class and has two derived classes ExternalCustomer and InternalCustomer. Table-per-concreteclass mapping is used. Invoice table has two columns for mapping the customer - customerType and customerId. CustomerType == 1 implies InternalCustomer, CustomerType == 2 implies ExternalCustomer.
InvoiceClass has a method called getCustomer()

<!-- Mapping snippet in Invoice table -->
<any name="customer" id-type="long" meta-type="com.example.hibernate.customtype.CustomerTypeMapper">
	<column name="customerType"/>
	<column name="customerId"/>
</any>

/***********************************************************
Class created by End User
***********************************************************/
public class CustomerTypeMapper extends ClassToIntegerMapper
{
	static public final Integer INTERNAL_CUSTOMER = new Integer(1);
	static public final Integer EXTERNAL_CUSTOMER = new Integer(2);
	
	static final private ClassToIntValue[] mappings =
	{
		new ClassToIntValue(INTERNAL_CUSTOMER, InternalCustomer.class),
		new ClassToIntValue(EXTERNAL_CUSTOMER, ExternalCustomer.class)
	};
	
	public ClassToIntValue[] getMappings()
	{
		return mappings;
	}

}

/***********************************************************
Class which reflects this patch itself
***********************************************************/
package com.example.hibernate.customtype;

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

import net.sf.hibernate.Hibernate;
import net.sf.hibernate.HibernateException;
import net.sf.hibernate.UserType;

/**
 * @author Dhananjay Nene
 */
abstract public class ClassToIntegerMapper implements UserType
{
	static final private int[] TYPES =  {Types.INTEGER };
	
	abstract public ClassToIntValue[] getMappings();

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

	public Class returnedClass()
	{
		return java.lang.Class.class;
	}

	public boolean equals(Object arg0, Object arg1) throws HibernateException
	{
		if (arg0 == arg1) return true;
		if ((arg0 == null) || (arg1 == null)) return false;
		return ((java.lang.Class) arg0).equals((java.lang.Class) arg1);
	}

	public Object nullSafeGet(ResultSet rs, String[] names, Object owner)
		throws HibernateException, SQLException
	{
		Integer result = (Integer) Hibernate.INTEGER.nullSafeGet(rs,names[0]);
		if(result == null)
		{
			return null;
		}
		ClassToIntValue[] mappings = getMappings();
		for(int i = 0 ; i < mappings.length ; i++)
		{
			if (result.equals(mappings[i].getIntVal()))
			{
				return mappings[i].getClazz();
			}
		}
		return null;
	}

	public void nullSafeSet(PreparedStatement stmt, Object value, int index)
		throws HibernateException, SQLException
	{
		java.lang.Class clazz = (java.lang.Class) value;
		if (clazz == null)
		{
			Hibernate.INTEGER.nullSafeSet(stmt,null,index);
			return;
		}
		Integer intval = null;
		ClassToIntValue[] mappings = getMappings();
		for(int i = 0 ; i < mappings.length ; i++)
		{
			if (clazz.equals(mappings[i].getClazz()))
			{
				intval = mappings[i].getIntVal();
			}
		}
		Hibernate.INTEGER.nullSafeSet(stmt,intval,index);
	}

	public Object deepCopy(Object arg0) throws HibernateException
	{
		if (arg0 == null) return null;
		Class clazz = (Class)arg0;
		Class newClazz = (Class) Hibernate.CLASS.deepCopy(clazz);
		return newClazz;
	}

	public boolean isMutable()
	{
		return false;
	}

}


---------------------------------------------------------------------
JIRA INFORMATION:
This message is automatically generated by JIRA.

If you think it was sent incorrectly contact one of the administrators:
   http://opensource.atlassian.com/projects/hibernate/secure/Administrators.jspa

If you want more information on JIRA, or have a bug to report see:
   http://www.atlassian.com/software/jira