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Various utility functions to validate user input.
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| package com.example.util; | |
| import android.text.TextUtils; | |
| import android.util.Patterns; | |
| import androidx.annotation.NonNull; | |
| import java.util.Objects; | |
| import java.util.regex.Matcher; | |
| import java.util.regex.Pattern; | |
| /** | |
| * Various utility functions to validate user input. | |
| * | |
| * @author Abdallah Abdelazim | |
| */ | |
| public final class InputValidationUtils { | |
| private InputValidationUtils() { | |
| // Prevent instantiation | |
| } | |
| /** | |
| * Checks that the passed string is a valid email address. | |
| * | |
| * @param email the string to validate. | |
| * @return true if {@code s} contains a valid email address, false otherwise. | |
| */ | |
| public static boolean isEmailValid(String email) { | |
| return (!TextUtils.isEmpty(email) && Patterns.EMAIL_ADDRESS.matcher(email).matches()); | |
| } | |
| /** | |
| * Checks if a given string contains any special characters. | |
| * <br> | |
| * A special character is any character that is not A-Z, a-z, 0-9 or any whitespace. | |
| * | |
| * @param s the string to validate. | |
| * @return true if {@code s} contains one or more special characters, | |
| * false if it contains no special characters at all. | |
| */ | |
| public static boolean containsSpecialChar(String s) { | |
| return isRegexMatch("[^a-zA-Z0-9\\s]", s); | |
| } | |
| /** | |
| * Checks if a given string starts with a special character. | |
| * <br> | |
| * A special character is any character that is not A-Z, a-z, 0-9 or any whitespace. | |
| * | |
| * @param s the string to validate. | |
| * @return true if the string starts with a special character while ignoring all | |
| * leading whitespaces, false otherwise. | |
| */ | |
| public static boolean isStartingWithSpecialChar(String s) { | |
| return isRegexMatch("^\\s*[^a-zA-Z0-9\\s](.|\\s)*$", s); | |
| } | |
| /** | |
| * Checks if a given string contains only special characters. | |
| * <br> | |
| * A special character is any character that is not A-Z, a-z, 0-9 or any whitespace. | |
| * | |
| * @param s the string to validate. | |
| * @return true if all the non-whitespace characters in the string are special characters, | |
| * false otherwise. | |
| */ | |
| public static boolean isAllSpecialChars(String s) { | |
| return isRegexMatch("^(\\s*[^a-zA-Z0-9\\s]\\s*)+$", s); | |
| } | |
| /** | |
| * Checks if a given string starts with an invalid character. | |
| * <br> | |
| * An invalid character is any punctuation or control character. | |
| * | |
| * @param s the string to validate. | |
| * @return true if the string starts with an invalid character while ignoring all | |
| * leading whitespaces, false otherwise. | |
| */ | |
| public static boolean isStartingWithInvalidChar(String s) { | |
| return isRegexMatch("^\\s*[\\p{Punct}\\p{Cntrl}](.|\\s)*$", s); | |
| } | |
| /** | |
| * Checks if a given string contains only invalid characters. | |
| * <br> | |
| * An invalid character is any punctuation or control character. | |
| * | |
| * @param s the string to validate. | |
| * @return true if all the non-whitespace characters in the string are invalid characters, | |
| * false otherwise. | |
| */ | |
| public static boolean isAllInvalidChars(String s) { | |
| return isRegexMatch("^(\\s*[\\p{Punct}\\p{Cntrl}]\\s*)+$", s); | |
| } | |
| private static boolean isRegexMatch(@NonNull String regex, String s) { | |
| if (s == null || s.isEmpty()) | |
| return false; | |
| Pattern pattern = Pattern.compile(Objects.requireNonNull(regex, | |
| "The passed regex string cannot be null")); | |
| Matcher matcher = pattern.matcher(s); | |
| return matcher.matches(); | |
| } | |
| } |
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