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Free Java Reporting Library
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/*
 * JasperReports - Free Java Reporting Library.
 * Copyright (C) 2001 - 2019 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.data;

import java.util.Collection;
import java.util.Iterator;

import net.sf.jasperreports.engine.JRException;
import net.sf.jasperreports.engine.JRField;


/**
 * A data source implementation that wraps a collection of JavaBean objects.
 * 
 * It is common to access application data through object persistence layers like EJB,
 * Hibernate, or JDO. Such applications may need to generate reports using data they
 * already have available as arrays or collections of in-memory JavaBean objects.
 * 
 * This JavaBean-compliant data source can be used when data comes in a 
 * java.util.Collection of JavaBean objects.
 * 
 * @author Teodor Danciu ([email protected])
 */
public class JRBeanCollectionDataSource extends JRAbstractBeanDataSource
{
	

	/**
	 *
	 */
	private Collection data;
	private Iterator iterator;
	private Object currentBean;
	

	/**
	 *
	 */
	public JRBeanCollectionDataSource(Collection beanCollection)
	{
		this(beanCollection, true);
	}
	

	/**
	 *
	 */
	public JRBeanCollectionDataSource(Collection beanCollection, boolean isUseFieldDescription)
	{
		super(isUseFieldDescription);
		
		this.data = beanCollection;

		if (this.data != null)
		{
			this.iterator = this.data.iterator();
		}
	}
	

	@Override
	public boolean next()
	{
		boolean hasNext = false;
		
		if (this.iterator != null)
		{
			hasNext = this.iterator.hasNext();
			
			if (hasNext)
			{
				this.currentBean = this.iterator.next();
			}
		}
		
		return hasNext;
	}
	
	
	@Override
	public Object getFieldValue(JRField field) throws JRException
	{
		return getFieldValue(currentBean, field);
	}

	
	@Override
	public void moveFirst()
	{
		if (this.data != null)
		{
			this.iterator = this.data.iterator();
		}
	}

	/**
	 * Returns the underlying bean collection used by this data source.
	 * 
	 * @return the underlying bean collection
	 */
	public Collection getData()
	{
		return data;
	}

	/**
	 * Returns the total number of records/beans that this data source
	 * contains.
	 * 
	 * @return the total number of records of this data source
	 */
	public int getRecordCount()
	{
		return data == null ? 0 : data.size();
	}
	
	/**
	 * Clones this data source by creating a new instance that reuses the same
	 * underlying bean collection. 
	 * 
	 * @return a clone of this data source
	 */
	public JRBeanCollectionDataSource cloneDataSource()
	{
		return new JRBeanCollectionDataSource(data);
	}
}