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EsperIO CSV
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/**************************************************************************************
 * Copyright (C) 2006-2015 EsperTech Inc. All rights reserved.                        *
 * http://www.espertech.com/esper                                                          *
 * http://www.espertech.com                                                           *
 * ---------------------------------------------------------------------------------- *
 * The software in this package is published under the terms of the GPL license       *
 * a copy of which has been included with this distribution in the license.txt file.  *
 **************************************************************************************/
package com.espertech.esperio.csv;

import java.util.Arrays;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import com.espertech.esper.client.EPException;

/**
 * A utility for resolving property order information based on a
 * propertyTypes map and the first record of a CSV file (which
 * might represent the title row).
 */
public class CSVPropertyOrderHelper
{
	private static final Log log = LogFactory.getLog(CSVPropertyOrderHelper.class);

	/**
	 * Resolve the order of the properties that appear in the CSV file,
	 * from the first row of the CSV file.
	 * @param firstRow - the first record of the CSV file
	 * @param propertyTypes - describes the event to send into the EPRuntime
	 * @return the property names in the order in which they occur in the file
	 */
	public static String[] resolvePropertyOrder(String[] firstRow, Map propertyTypes)
	{
		log.debug(".resolvePropertyOrder firstRow==" + Arrays.asList(firstRow));
		String[] result = null;

		if(isValidTitleRow(firstRow, propertyTypes))
		{
			result = firstRow;
			log.debug(".resolvePropertyOrder using valid title row, propertyOrder==" + Arrays.asList(result));
		}
		else
		{
			throw new EPException("Cannot resolve the order of properties in the CSV file");
		}

		return result;
	}

	private static boolean isValidTitleRow(String[] row, Map propertyTypes)
	{
		if(propertyTypes == null)
		{
			return true;
		}
		else
		{
			return isValidRowLength(row, propertyTypes) && eachPropertyNameRepresented(row, propertyTypes);
		}
	}

	private static boolean eachPropertyNameRepresented(String[] row, Map propertyTypes)
	{
		Set rowSet = new HashSet(Arrays.asList(row));
		return rowSet.containsAll(propertyTypes.keySet());
	}

	private static boolean isValidRowLength(String[] row, Map propertyTypes)
	{
		log.debug(".isValidRowLength");
		if(row == null)
		{
			return false;
		}
		// same row size, or with timestamp column added, or longer due to flatten nested properties
		return ( row.length == propertyTypes.size() ) || ( row.length == propertyTypes.size() + 1 ) || (row.length > propertyTypes.size());
	}

}