http://opencsv.sf.net: A simple library for reading and writing CSV in Java
  • Glen Smith
  • Tom Squires
  • Maciek Opala
  • J.C. Romanda
  • Sean Sullivan
  • Kyle Miller
  • Vladimir Dolzhenko
  • Scott Conway
  • Andrew Rucker Jones 
package com.opencsv.bean.validators;

import com.opencsv.bean.BeanField;
import com.opencsv.exceptions.CsvValidationException;


This is the interface for validators for a single String value. 
Currently this is used by the PreAssignmentValidator to check the value of a string before time is taken to convert it.


For post-conversion validation there are already a plethora of third
party libraries that can be incorporated into the bean, or you can
just modify the setter to validate inputs.


Author:Scott Conway
Since:5.0
/**
 * This is the interface for validators for a single
 * {@link java.lang.String} value.
 * <p>Currently this is used by the {@link PreAssignmentValidator} to check the
 * value of a string before time is taken to convert it.</p>
 * <p>For post-conversion validation there are already a plethora of third
 * party libraries that can be incorporated into the bean, <em>or</em> you can
 * just modify the setter to validate inputs.</p>
 *
 * @author Scott Conway
 * @since 5.0
 */
public interface StringValidator {
    
Performs the validation check on the string and returns the result.

Params:
  • value – String to be validated
Returns:true if the value is valid, false otherwise
/**
     * Performs the validation check on the string and returns the result.
     *
     * @param value String to be validated
     * @return {@code true} if the value is valid, {@code false} otherwise
     */
    boolean isValid(String value);

    
Performs the validation check on the string and throws an exception if
invalid.

Params:
  • value – String to be validated
  • field – Name of the field in the bean. This will be used in the CsvValidationException if the value is not valid.
Throws:
/**
     * Performs the validation check on the string and throws an exception if
     * invalid.
     *
     * @param value String to be validated
     * @param field Name of the field in the bean.  This will be used in
     *                  the {@link CsvValidationException} if the value is not
     *                  valid.
     * @throws CsvValidationException If the input is invalid. Should contain a
     * message describing the error.
     */
    void validate(String value, BeanField field) throws CsvValidationException;

    
This allows the validator extending StringValidator to be used by multiple fields by allowing you to pass in data for the validator to be used. 
Those data might be forbidden characters or regular expressions, to
name two possibilities.


If the validator needs multiple parameters, then you will need to
combine them into a single string using some sort of delimiter, say a
comma, and parse them out using some library that allows you to parse
such strings 😁.


If the validator does not need a value then just create an empty
method like the MustStartWithACapitalLetter validator used by the
BeanFieldValidatorTest.


Params:
  • value – Information used by the validator to validate the string
/**
     * This allows the validator extending {@link StringValidator} to be used
     * by multiple fields by allowing you to pass in data for the validator to
     * be used.
     * <p>Those data might be forbidden characters or regular expressions, to
     * name two possibilities.</p>
     * <p>If the validator needs multiple parameters, then you will need to
     * combine them into a single string using some sort of delimiter, say a
     * comma, and parse them out using some library that allows you to parse
     * such strings 😁.</p>
     * <p>If the validator does not need a value then just create an empty
     * method like the MustStartWithACapitalLetter validator used by the
     * BeanFieldValidatorTest.</p>
     *
     * @param value Information used by the validator to validate the string
     */
    void setParameterString(String value);
}