Bug 192083 [regression]DataException when preview attached xtab report.[1102]
data/org.eclipse.birt.report.data.adapter/src/org/eclipse/birt/report/data/adapter/impl/DataRequestSessionImpl.java
*/
	public IPreparedQuery prepare( IQueryDefinition query, Map appContext )
			throws BirtException
	{
		if ( appContext == null )
			
			appContext = sessionContext.getAppContext( );
		return dataEngine.prepare( query, appContext );
	}
	/**
	 * @see org.eclipse.birt.report.data.adapter.api.DataRequestSession#prepare(org.eclipse.birt.data.engine.api.IQueryDefinition)
	 */
	public IPreparedQuery prepare(IQueryDefinition query) throws BirtException
	{
		
		return dataEngine.prepare( query, this.sessionContext.getAppContext() );
	}
	/*
	 * @see org.eclipse.birt.report.data.adaptor.impl.IDataRequestSession#closeDataSource(java.lang.String)
	 */
	public void closeDataSource( String dataSourceName ) throws BirtException
	{
		dataEngine.closeDataSource( dataSourceName );
	}
	/*
	 * @see org.eclipse.birt.report.data.adaptor.impl.IDataRequestSession#getModelAdaptor()
	 */
	public IModelAdapter getModelAdaptor( )
	{
		return modelAdaptor;