package org.msh.reports.tableoperations;

import org.msh.reports.datatable.DataTable;
import org.msh.reports.datatable.Row;
import org.msh.reports.datatable.impl.DataTableImpl;

/**
 * Concatenates two tables vertically, i.e, creates a new {@link DataTableImpl}
 * which will contain all rows of both data tables. The two source data tables
 * must have the same columns
 *  
 * @author Ricardo Memoria
 *
 */
public class ConcatTables {

	/**
	 * Concatenate the rows of two data tables
	 * @param tbl1
	 * @param tbl2
	 * @return a new instance of the {@link DataTableImpl} containing all rows
	 */
	public static DataTable concatenate(DataTable tbl1, DataTable tbl2) {
		DataTableImpl target = new DataTableImpl(tbl1.getColumnCount(), 0);
		insertRows(target, tbl1);
		insertRows(target, tbl2);
		return target;
	}
	
	
	/**
	 * Insert rows from data table source into data table target
	 * @param target
	 * @param source
	 * @return
	 */
	public static void insertRows(DataTable target, DataTable source) {
		// check if source table fits on target table
		while (target.getColumnCount() < source.getColumnCount())
			target.addColumn();
		
		for (Row row: source.getRows()) {
			Row trow = target.addRow();
			int index = 0;
			for (Object value: row.getValues())
				trow.setValue(index++, value);
		}
	}
}