package innovimax.mixthem.operation;

import innovimax.mixthem.MixException;
import innovimax.mixthem.arguments.ParamValue;
import innovimax.mixthem.arguments.RuleParam;

import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

/**
* <p>Joins two lines on a common field.</p>
* @see ILineOperation
* @author Innovimax
* @version 1.0
*/
public class DefaultLineJoining extends AbstractLineOperation {
	
	private final int col1;
	private final int col2;
	
	/**
 	* @param params The list of parameters (maybe empty)
	* @see innovimax.mixthem.operation.RuleParam
	* @see innovimax.mixthem.operation.ParamValue
	*/
	public DefaultLineJoining(Map<RuleParam, ParamValue> params) {
		super(params);
		this.col1 = this.params.containsKey(RuleParam.JOIN_COL1) ? this.params.get(RuleParam.JOIN_COL1).asInt() : JoinOperation.DEFAULT_JOIN_COLUMN.toInteger();
		this.col2 = this.params.containsKey(RuleParam.JOIN_COL2) ? this.params.get(RuleParam.JOIN_COL2).asInt() : JoinOperation.DEFAULT_JOIN_COLUMN.toInteger();
	}	

	@Override
	public void process(String line1, String line2, LineResult result) throws MixException {
		result.reset();
		if (line1 != null && line2 != null) {
			List<String> list1 = Arrays.asList(line1.split(CellOperation.DEFAULT_SPLIT_CELL_REGEX.toString()));
			List<String> list2 = Arrays.asList(line2.split(CellOperation.DEFAULT_SPLIT_CELL_REGEX.toString()));		
			String cell1 = list1.size() >= this.col1 ? list1.get(this.col1 - 1) : null;
      		String cell2 = list2.size() >= this.col2 ? list1.get(this.col2 - 1) : null;
			if (cell1 != null && cell2 != null) {
				switch (cell1.compareTo(cell2)) {
					case 0:
						String part1 = list1.get(this.col1 - 1);
						String part2 = list1.stream().filter(s -> !s.equals(part1)).collect(Collectors.joining(CellOperation.DEFAULT_CELL_SEPARATOR.toString()));
						String part3 = list2.stream().filter(s -> !s.equals(part1)).collect(Collectors.joining(CellOperation.DEFAULT_CELL_SEPARATOR.toString()));
						result.setResult(part1 + CellOperation.DEFAULT_CELL_SEPARATOR.toString()  + 
								 part2 + CellOperation.DEFAULT_CELL_SEPARATOR.toString() + part3);
						result.exploreBothFiles();
						break;
					case 1:
						result.preserveFirstLine();
						break;
					default:
						result.preserveSecondLine();
				}
			}
		}
	}

}

package innovimax.mixthem.operation;

import innovimax.mixthem.MixException;
import innovimax.mixthem.arguments.ParamValue;
import innovimax.mixthem.arguments.RuleParam;

import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

/**
* <p>Joins two lines on a common field.</p>
* @see ILineOperation
* @author Innovimax
* @version 1.0
*/
public class DefaultLineJoining extends AbstractLineOperation {
	
	private final int col1;
	private final int col2;
	
	/**
 	* @param params The list of parameters (maybe empty)
	* @see innovimax.mixthem.operation.RuleParam
	* @see innovimax.mixthem.operation.ParamValue
	*/
	public DefaultLineJoining(Map<RuleParam, ParamValue> params) {
		super(params);
		this.col1 = this.params.containsKey(RuleParam.JOIN_COL1) ? this.params.get(RuleParam.JOIN_COL1).asInt() : JoinOperation.DEFAULT_JOIN_COLUMN.toInteger();
		this.col2 = this.params.containsKey(RuleParam.JOIN_COL2) ? this.params.get(RuleParam.JOIN_COL2).asInt() : JoinOperation.DEFAULT_JOIN_COLUMN.toInteger();
	}	

	@Override
	public void process(String line1, String line2, LineResult result) throws MixException {
		result.reset();
		if (line1 != null && line2 != null) {
			List<String> list1 = Arrays.asList(line1.split(CellOperation.DEFAULT_SPLIT_CELL_REGEX.toString()));
			List<String> list2 = Arrays.asList(line2.split(CellOperation.DEFAULT_SPLIT_CELL_REGEX.toString()));		
			String cell1 = list1.size() >= this.col1 ? list1.get(this.col1 - 1) : null;
			String cell2 = list2.size() >= this.col2 ? list1.get(this.col2 - 1) : null;
			if (cell1 != null && cell2 != null) {
				switch (cell1.compareTo(cell2)) {
					case 0:
						String part1 = list1.get(this.col1 - 1);
						String part2 = list1.stream().filter(s -> !s.equals(part1)).collect(Collectors.joining(CellOperation.DEFAULT_CELL_SEPARATOR.toString()));
						String part3 = list2.stream().filter(s -> !s.equals(part1)).collect(Collectors.joining(CellOperation.DEFAULT_CELL_SEPARATOR.toString()));
						result.setResult(part1 + CellOperation.DEFAULT_CELL_SEPARATOR.toString()  + 
								 part2 + CellOperation.DEFAULT_CELL_SEPARATOR.toString() + part3);
						result.exploreBothFiles();
						break;
					case 1:
						result.preserveFirstLine();
						break;
					default:
						result.preserveSecondLine();
				}
			}
		}
	}

}

Update DefaultLineJoining.java