Im beginning with Castor and have a problem with loading instances of an
inherited class from the database via a generic Vector.
My classes are the following:
Product (generic class, table PRODUCT)
Computer extends Product (table COMPUTER)
ProductSuite (table PRODSUITE) - has a Vector of Products: private
Vector vProduct;
When I create a ProductSuite with a Computer object on the Vector as
result I get 3 records - one on each table; thats why I think, that the
extends relationship is able to work properly.
The problem occurs when I try to load the ProductSuite from the database
and to remove it - now I get a ProductSuite object with a pure Product
object on the Vector vProduct and the Computer record will not be loaded
nor removed. What is my mistake? What do I have to change?
My source code (mapping file, Product.java, InheritanceTeste1.java):
*** mapping.xml ***
<!DOCTYPE databases PUBLIC "-//EXOLAB/Castor Mapping DTD Version
1.0//EN"
"http://castor.exolab.org/mapping.dtd";>
<mapping>
<!-- Mapping for ProductSuite -->
<class name="inheritancetest1.ProductSuite"
identity="id">
<description>Product definition</description>
<map-to table="prodsuite" xml="productsuite" />
<field name="id" type="integer">
<sql name="id" type="integer" />
<xml name="id" node="attribute"/>
</field>
<field name="suitename" type="string">
<sql name="suitename" type="char" />
<xml name="suitename" node="attribute" />
</field>
<!-- Zugangsstelle has reference to Product
many products per productsuite -->
<field name="vProduct" type="inheritancetest1.Product"
required="true"
collection="vector">
<sql many-key="prodsuite_id"/>
<xml name="product" node="element" />
</field>
</class>
<!-- Mapping for Product -->
<class name="inheritancetest1.Product"
identity="id" depends="inheritancetest1.ProductSuite"
subclass-field="subclass">
<description>Product definition</description>
<map-to table="prod" xml="product" />
<field name="id" type="integer">
<sql name="id" type="integer" />
<xml name="id" node="attribute"/>
</field>
<field name="name" type="string">
<sql name="name" type="char" />
<xml name="name" node="attribute" />
</field>
<field name="price" type="float">
<sql name="price" type="numeric" />
<xml name="price" node="attribute" />
</field>
<field name="productsuite_id" type="integer">
<sql name="prodsuite_id" type="integer" />
<xml name="prodsuite_id" node="attribute"/>
</field>
<field name="subclass" type="string">
<sql name="subclass" type="char" />
<xml name="subclass" node="element" />
</field>
</class>
<!-- Mapping for Computer, extending Product -->
<class name="inheritancetest1.Computer"
extends="inheritancetest1.Product" identity="id">
<description>Computer definition, extends generic
product</description>
<map-to table="computer" xml="computer" />
<field name="id" type="integer">
<sql name="id" type="integer" />
<xml name="id" node="attribute"/>
</field>
<field name="cpu" type="string">
<sql name="cpu" type="char"/>
<xml name="cpu" node="attribute" />
</field>
</class>
</mapping>
*** Product.java ***
/* Generated by Together */
package inheritancetest1;
import java.util.Vector;
import java.util.Enumeration;
import org.exolab.castor.jdo.Database;
import org.exolab.castor.jdo.Persistent;
public class Product implements Persistent {
private int _id;
private String _name;
private float _price;
private int _productsuite_id;
private String _subclass;
private Database _db;
public int getId()
{
return _id;
}
public void setId( int id )
{
_id = id;
}
public String getName()
{
return _name;
}
public void setName( String name )
{
_name = name;
}
public float getPrice()
{
return _price;
}
public void setPrice( float price )
{
_price = price;
}
public int getProductsuite_id()
{
return _productsuite_id;
}
public void setProductsuite_id( int productsuite_id )
{
_productsuite_id = productsuite_id;
}
public String getSubclass()
{
return _subclass;
}
public void setSubclass( String subclass )
{
_subclass = subclass;
}
public void jdoPersistent( Database db )
{
_db = db;
}
public void jdoTransient()
{
_db = null;
}
public Class jdoLoad(short accessMode)
{
if ( _subclass.indexOf("Computer") >= 0 ) {
return Computer.class;
}
return null;
}
public void jdoBeforeCreate( Database db )
{
}
public void jdoAfterCreate()
{
}
public void jdoStore(boolean modified)
{
}
public void jdoBeforeRemove()
{
}
public void jdoAfterRemove()
{
}
public void jdoUpdate()
{
}
public String toString()
{
return _id + " " + _name;
}
}
*** InheritanceTest1.java ***
/* Generated by Together */
package inheritancetest1;
import java.util.Hashtable;
import java.util.Vector;
import java.util.Enumeration;
import java.io.PrintWriter;
import java.io.InputStreamReader;
import java.io.Serializable;
import java.io.FileOutputStream;
import java.io.File;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.DriverManager;
import javax.sql.*;
import java.sql.*;
import org.xml.sax.ContentHandler;
import org.exolab.castor.jdo.JDO;
import org.exolab.castor.jdo.Database;
import org.exolab.castor.jdo.OQLQuery;
import org.exolab.castor.jdo.QueryResults;
import org.exolab.castor.util.Logger;
import org.exolab.castor.xml.Marshaller;
import org.exolab.castor.mapping.Mapping;
import org.apache.xml.serialize.*;
import oracle.jdbc.*;
public class InheritanceTest1 {
public static final String DatabaseFile = "database.xml";
public static final String MappingFile = "mapping.xml";
public static final String Usage = "Usage: example jdo";
private Mapping _mapping;
private JDO _jdo;
public static void main( String[] args )
{
PrintWriter writer;
InheritanceTest1 test;
// writer = new Logger( System.out ).setPrefix( "test" );
writer = new Logger( System.out ).setPrefix( "test" );
try {
test = new InheritanceTest1 ( writer );
test.run( writer );
} catch ( Exception except ) {
writer.println( except );
except.printStackTrace( writer );
}
}
public InheritanceTest1( PrintWriter writer )
throws Exception
{
// Load the mapping file
_mapping = new Mapping( getClass().getClassLoader() );
_mapping.setLogWriter( writer );
_mapping.loadMapping( /*getClass().getResource(*/ MappingFile
/*)*/ );
_jdo = new JDO();
_jdo.setLogWriter( writer );
_jdo.setConfiguration( /*getClass().getResource(*/ DatabaseFile
/*).toString()*/ );
_jdo.setDatabaseName( "test" );
}
public void run( PrintWriter writer )
throws Exception
{
Database db;
ProductSuite productsuite;
Product product;
Computer computer;
OQLQuery productsuiteOql;
OQLQuery productOql;
OQLQuery computerOql;
QueryResults results;
db = _jdo.getDatabase();
db.begin();
writer.println( "Begin transaction" );
// Look up the product and if found in the database,
// delete this object from the database
productsuiteOql = db.getOQLQuery( "SELECT p FROM
inheritancetest1.ProductSuite p WHERE id = $1" );
productsuiteOql.bind( 2 );
results = productsuiteOql.execute();
while ( results.hasMore() ) {
productsuite = (ProductSuite) results.next();
writer.println( "Deleting existing productsuite: " +
productsuite );
db.remove( productsuite );
}
// Checkpoint commits all the updates to the database
// but leaves the transaction (and locks) open
writer.println( "Transaction checkpoint" );
db.commit();
db.begin();
// If no such product exists in the database, create a new
// object and persist it
// Note: product uses group, so group object has to be
// created first, but can be persisted later
productsuiteOql.bind( 2 );
results = productsuiteOql.execute();
if ( ! results.hasMore() ) {
productsuite = new ProductSuite();
productsuite.setId( 2 );
productsuite.setSuitename( "product suite A" );
computer = new Computer();
computer.setId( 6 );
computer.setCpu( "Pentium" );
computer.setName( "MyPC" );
computer.setPrice( 300 );
computer.setSubclass("inheritancetest1.Computer");
productsuite.addVProduct(computer);
writer.println( "Creating new productsuite: " + productsuite
);
db.create( productsuite );
} else {
writer.println( "Query result: " + results.next() );
}
// If no such computer exists in the database, create a new
// object and persist it
// Note: computer uses group, so group object has to be
// created first, but can be persisted later
writer.println( "Commit transaction" );
db.commit();
db.close();
}
}
-----------------------------------------------------------
If you wish to unsubscribe from this mailing, send mail to
[EMAIL PROTECTED] with a subject of:
unsubscribe castor-dev
