/*
 * StreamableMapping.java
 *
 * Created on 7 October 2006, 16:58
 *
 * To change this template, choose Tools | Template Manager
 * and open the template in the editor.
 */

package au.org.kaizen.jdo;

import javax.jdo.JDOFatalException;
import org.apache.log4j.Logger;
import org.jpox.ClassLoaderResolver;
import org.jpox.metadata.AbstractPropertyMetaData;
import org.jpox.store.DatastoreAdapter;
import org.jpox.store.DatastoreContainerObject;
import org.jpox.store.expression.LogicSetExpression;
import org.jpox.store.expression.QueryExpression;
import org.jpox.store.expression.ScalarExpression;
import org.jpox.store.mapping.SingleFieldMapping;

/**
 * Represents the class mapping for the StreamableObjet class
 * @author swhitehead
 */
public class StreamableMapping extends SingleFieldMapping
{
    
    private Logger logger;

    /**
     * Constructor for a mapping used by a Query.
     * @param dba Datastore Adapter
     * @param type Type of the field
     */
    public StreamableMapping(DatastoreAdapter dba, String type)
    {
        super(dba, type);
    }

    /**
     * Constructor for a mapping used by a datastore representation.
     * @param dba Datastore Adapter
     * @param fmd AbstractPropertyMetaData for the field being mapped
     * @param datastoreContainer Table containing the mapped object
     */
    public StreamableMapping(DatastoreAdapter dba, AbstractPropertyMetaData fmd, DatastoreContainerObject datastoreContainer)
    {
        super(dba, fmd, datastoreContainer);
    }

    /**
     * Constructor for a mapping used by a datastore representation.
     * @param clr Classloader resolver
     * @param dba Datastore Adapter
     * @param fmd AbstractPropertyMetaData for the field being mapped
     * @param datastoreContainer Table containing the mapped object
     */
    public StreamableMapping(DatastoreAdapter dba, AbstractPropertyMetaData fmd, DatastoreContainerObject datastoreContainer, ClassLoaderResolver clr)
    {
        super(dba, fmd, datastoreContainer);
    }
    
    /**
     * Convient method for obtaining the logger for this class
     * @return A logger suitable for logging
     */
    protected Logger getLogger()
    {
        if (logger == null)
        {
            logger = Logger.getLogger(StreamableMapping.class);
        }
        
        return logger;
    }

    /**
     * Returns the Java class type represented by this mapping
     * @return Returns StreamableObject.class
     */
    public Class getJavaType()
    {
        return StreamableObject.class;
    }

    /**
     * Returns a sample StreamableObject
     * @param classLoaderResolver ClassLoaderResolver
     * @return A new instance of StreamableObject
     */
    public Object getSampleValue(ClassLoaderResolver classLoaderResolver)
    {
        return new StreamableObject(null);
    }

    /**
     * Overwritten to throw an error. It is not possible to include a streamable
     * object in a query
     * @param qExpr QueryExpression
     * @param literal Object literal
     * @return Returns nothing - throws Fatal Exception
     */
    public ScalarExpression newLiteral(QueryExpression qExpr, Object literal)
    {
        throw new JDOFatalException(getJavaType().getName()+" is not supported in queries.");
    }

    /**
     * Overwritten to throw an error. It is not possible to include a streamable
     * object in a query
     * @param qExpr QueryExpression
     * @param expr LogicalSetExpression
     * @return Returns nothing - throws Fatal Exception
     */
    public ScalarExpression newScalarExpression(QueryExpression qExpr, LogicSetExpression expr)
    {
        throw new JDOFatalException(getJavaType().getName()+" is not supported in queries.");
    }
    
}