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/*
 * JasperReports - Free Java Reporting Library.
 * Copyright (C) 2001 - 2014 TIBCO Software Inc. All rights reserved.
 * http://www.jaspersoft.com
 *
 * Unless you have purchased a commercial license agreement from Jaspersoft,
 * the following license terms apply:
 *
 * This program is part of JasperReports.
 *
 * JasperReports is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * JasperReports is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with JasperReports. If not, see .
 */
package net.sf.jasperreports.engine;

import java.util.List;

/**
 * Interface of an sub dataset instantiation.
 * 
 * Once a dataset is declared inside a report template, it can be used only if it's actually
 * referenced by a chart, crosstab or other component. Simply declaring a dataset at the report 
 * level does not have any effect.
 * 

 * When a dataset is referenced by a report component, a dataset run is instantiated. The
 * dataset runs through the supplied data source performing all the variable calculations and
 * the required data grouping.
 * 

 * A dataset run declaration supplies the values for the dataset parameters as well as the
 * data source through which the dataset will iterate. Optionally, a java.sql.Connection
 * can be passed to the dataset instead of a {@link net.sf.jasperreports.engine.JRDataSource} instance, 
 * when there is a SQL query associated with the dataset. This query is executed by the engine using the
 * JDBC connection and the java.sql.ResultSet object obtained is iterated through.
 * 

 * Dataset runs resemble subreports in the way parameters and the data source/connection
 * are passed in.
 * 

 * Charts, crosstabs and other report components can reference datasets by instantiating and configuring dataset
 * runs. If no dataset run is specified for a component, the main dataset of the report is
 * used.
 * 
 * @see net.sf.jasperreports.engine.JRDataset
 * @see net.sf.jasperreports.engine.JRChartDataset#getDatasetRun()
 * @author Lucian Chirita ([email protected])
 */
public interface JRDatasetRun extends JRCloneable, JRIdentifiable, JRPropertiesHolder
{
	/**
	 * Returns the sub dataset name.
	 * 
	 * @return the sub dataset name
	 */
	public String getDatasetName();
	
	
	/**
	 * Returns the parameters map expression.
	 * 

	 * The result of this expression is used as the parameters map when instantiating the dataset.
	 * 
	 * @return the parameters map expression
	 */
	public JRExpression getParametersMapExpression();
	
	
	/**
	 * Returns the list of parameter values.
	 * 
	 * @return the list of parameter values
	 */
	public JRDatasetParameter[] getParameters();

	
	/**
	 * Returns the DB connection expression.
	 * 

	 * The result of this expression is used as the DB connection when instantiating the dataset.
	 * 
	 * @return the DB connection expression
	 */
	public JRExpression getConnectionExpression();

	
	/**
	 * Returns the data source expression.
	 * 
	 * The result of this expression is used as the data source when instantiating the dataset.
	 * 
	 * @return the data source expression
	 */
	public JRExpression getDataSourceExpression();
	
	/**
	 * Returns the list of values to be copied from the subdataset.
	 *
	 * @return the list of copied values.
	 */
	public List getReturnValues();

}