I was curious about the contents of the validator of javax.validation.constraints.NotBlank
, so I checked it.
A code that returns true if it is blank
.
public boolean isBlank(CharSequence charSequence) {
if ( charSequence == null ) {
return true;
}
return charSequence.toString().trim().length() == 0;
}
This code is borrowed from the implementation of ʻorg.hibernate.validator.internal.constraintvalidators.bv.NotBlankValidator`.
/*
* Hibernate Validator, declare and validate application constraints
*
* License: Apache License, Version 2.0
* See the license.txt file in the root directory or <http://www.apache.org/licenses/LICENSE-2.0>.
*/
package org.hibernate.validator.internal.constraintvalidators.bv;
import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;
import javax.validation.constraints.NotBlank;
/**
* Check that a character sequence is not {@code null} nor empty after removing any leading or trailing whitespace.
*
* @author Guillaume Smet
*/
public class NotBlankValidator implements ConstraintValidator<NotBlank, CharSequence> {
/**
* Checks that the character sequence is not {@code null} nor empty after removing any leading or trailing
* whitespace.
*
* @param charSequence the character sequence to validate
* @param constraintValidatorContext context in which the constraint is evaluated
* @return returns {@code true} if the string is not {@code null} and the length of the trimmed
* {@code charSequence} is strictly superior to 0, {@code false} otherwise
*/
@Override
public boolean isValid(CharSequence charSequence, ConstraintValidatorContext constraintValidatorContext) {
if ( charSequence == null ) {
return false;
}
return charSequence.toString().trim().length() > 0;
}
}
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