package com.opencsv.validators;

import com.opencsv.exceptions.CsvValidationException;

This validator is used when the number of columns is not neccessarily known but must be consistent.
The first row validated will always be considered valid, unless null or empty, and after that the each
subsequent row must have the same number of columns as the first.

Arrays that are empty or null are considered to have 0 elements.  An empty or null first row is considered
invalid.

As with all row validators the assumption is you have control of the data and have skipped any initial
empty lines.    If you have data that has empty lines or separators lines in your data then you should not
use this class.   Either extend it or write your own validator.
Author:
Scott Conway
Since:
5.0/**
 * This validator is used when the number of columns is not neccessarily known but must be consistent.
 * The first row validated will always be considered valid, unless null or empty, and after that the each
 * subsequent row must have the same number of columns as the first.
 * <p>
 * Arrays that are empty or null are considered to have 0 elements.  An empty or null first row is considered
 * invalid.
 * <p>
 * As with all row validators the assumption is you have control of the data and have skipped any initial
 * empty lines.    If you have data that has empty lines or separators lines in your data then you should not
 * use this class.   Either extend it or write your own validator.
 *
 * @author Scott Conway
 * @since 5.0
 */
public class RowMustHaveSameNumberOfColumnsAsFirstRowValidator implements RowValidator {
    private static final int NO_ROWS = 0;
    private int numRows = NO_ROWS;

    
Default constructor.
/**
     * Default constructor.
     */
    public RowMustHaveSameNumberOfColumnsAsFirstRowValidator() {
    }

    @Override
    public boolean isValid(String[] row) {
        if (row == null || row.length == 0) {
            return false;
        }

        if (firstRowNotSetYet()) {
            numRows = row.length;
        }
        return row.length == numRows;
    }

    @Override
    public void validate(String[] row) throws CsvValidationException {
        if (!isValid(row)) {
            if (firstRowNotSetYet()) {
                throw new CsvValidationException("First row should not be empty or null");
            } else if (row == null || row.length == 0) {
                throw new CsvValidationException("Row should not be empty or null");
            } else {
                throw new CsvValidationException(String.format("Row was expected to have %d elements but had %d instead", numRows, row.length));
            }

        }
    }

    private boolean firstRowNotSetYet() {
        return numRows == NO_ROWS;
    }
}