Package com.helger.commons.regex

Class RegExHelper

java.lang.Object
com.helger.commons.regex.RegExHelper
@Immutable public final class RegExHelper extends Object
This class offers helper methods that work on cached regular expression pattern as offered by RegExCache.
Author:
Philip Helger

  • Method Details

    • getSplitToArray

      @Nonnull public static String[] getSplitToArray(@Nullable CharSequence sText, @Nonnull @RegEx String sRegEx)
      Split the passed text with the given regular expression. If you do not need a regular expression, StringHelper.getExploded(String, String) is a faster option.
      Parameters:
      sText - The text to be split. May be null.
      sRegEx - The regular expression to use for splitting. May neither be null nor empty.
      Returns:
      An empty array if the text is null, a non- null array otherwise. If both text and regular expression are null an empty array is returned as well since the text parameter is checked first.

    • getSplitToArray

      @Nonnull public static String[] getSplitToArray(@Nullable CharSequence sText, @Nonnull @RegEx String sRegEx, @Nonnegative int nLimit)
      Split the passed text with the given regular expression returning at most the given number of tokens. If you do not need a regular expression, StringHelper.getExploded(String, String, int) is a faster option.
      Parameters:
      sText - The text to be split. May be null.
      sRegEx - The regular expression to use for splitting. May neither be null nor empty.
      nLimit - The maximum number of tokens to return if the value is > 0. If the value is ≤ 0 it has no effect and all tokens are returned.
      Returns:
      An empty array if the text is null, a non- null array otherwise. If both text and regular expression are null an empty array is returned as well since the text parameter is checked first.

    • getSplitToList

      @Nonnull public static ICommonsList<String> getSplitToList(@Nullable CharSequence sText, @Nonnull @RegEx String sRegEx)
      Split the passed text with the given regular expression. If you do not need a regular expression, StringHelper.getExploded(String, String) is a faster option.
      Parameters:
      sText - The text to be split. May be null.
      sRegEx - The regular expression to use for splitting. May neither be null nor empty.
      Returns:
      An empty list if the text is null, a non- null list otherwise. If both text and regular expression are null an empty list is returned as well since the text parameter is checked first.

    • getSplitToList

      @Nonnull public static ICommonsList<String> getSplitToList(@Nullable CharSequence sText, @Nonnull @RegEx String sRegEx, @Nonnegative int nLimit)
      Split the passed text with the given regular expression. If you do not need a regular expression, StringHelper.getExploded(String, String, int) is a faster option.
      Parameters:
      sText - The text to be split. May be null.
      sRegEx - The regular expression to use for splitting. May neither be null nor empty.
      nLimit - The maximum number of tokens to return if the value is > 0. If the value is ≤ 0 it has no effect and all tokens are returned.
      Returns:
      An empty list if the text is null, a non- null list otherwise. If both text and regular expression are null an empty list is returned as well since the text parameter is checked first.

    • getMatcher

      @Nonnull public static Matcher getMatcher(@Nonnull @RegEx String sRegEx, @Nonnull String sValue)
      Get the Java Matcher object for the passed pair of regular expression and value.
      Parameters:
      sRegEx - The regular expression to use. May neither be null nor empty.
      sValue - The value to create the matcher for. May not be null.
      Returns:
      A non-null matcher.

    • getMatcher

      @Nonnull public static Matcher getMatcher(@Nonnull @RegEx String sRegEx, @Nonnegative int nOptions, @Nonnull String sValue)
      Get the Java Matcher object for the passed pair of regular expression and value.
      Parameters:
      sRegEx - The regular expression to use. May neither be null nor empty.
      nOptions - The pattern compilations options to be used.
      sValue - The value to create the matcher for. May not be null.
      Returns:
      A non-null matcher.
      See Also:

    • stringMatchesPattern

      public static boolean stringMatchesPattern(@Nonnull @RegEx String sRegEx, @Nonnull String sValue)
      A shortcut helper method to determine whether a string matches a certain regular expression or not.
      Parameters:
      sRegEx - The regular expression to be used. The compiled regular expression pattern is cached. May neither be null nor empty.
      sValue - The string value to compare against the regular expression.
      Returns:
      true if the string matches the regular expression, false otherwise.

    • stringMatchesPattern

      public static boolean stringMatchesPattern(@Nonnull @RegEx String sRegEx, @Nonnegative int nOptions, @Nonnull String sValue)
      A shortcut helper method to determine whether a string matches a certain regular expression or not.
      Parameters:
      sRegEx - The regular expression to be used. The compiled regular expression pattern is cached. May neither be null nor empty.
      nOptions - The pattern compilations options to be used.
      sValue - The string value to compare against the regular expression.
      Returns:
      true if the string matches the regular expression, false otherwise.
      See Also:

    • stringReplacePattern

      @Nonnull public static String stringReplacePattern(@Nonnull @RegEx String sRegEx, @Nonnull String sValue, @Nullable String sReplacement)

    • stringReplacePattern

      @Nonnull public static String stringReplacePattern(@Nonnull @RegEx String sRegEx, @Nonnegative int nOptions, @Nonnull String sValue, @Nullable String sReplacement)

    • getAsIdentifier

      @Nullable public static String getAsIdentifier(@Nullable String s)
      Convert an identifier to a programming language identifier by replacing all non-word characters with an underscore ("_").
      Parameters:
      s - The string to convert. May be null or empty.
      Returns:
      The converted string or null if the input string is null.

    • getAsIdentifier

      @Nullable public static String getAsIdentifier(@Nullable String s, char cReplacement)
      Convert an identifier to a programming language identifier by replacing all non-word characters with an underscore.
      Parameters:
      s - The string to convert. May be null or empty.
      cReplacement - The replacement character to be used for all non-identifier characters
      Returns:
      The converted string or null if the input string is null.

    • getAsIdentifier

      @Nullable public static String getAsIdentifier(@Nullable String s, @Nonnull String sReplacement)
      Convert an identifier to a programming language identifier by replacing all non-word characters with an underscore.
      Parameters:
      s - The string to convert. May be null or empty.
      sReplacement - The replacement string to be used for all non-identifier characters. May be empty but not be null.
      Returns:
      The converted string or null if the input string is null. Maybe an invalid identifier, if the replacement is empty, and the identifier starts with an illegal character, or if the replacement is empty and the source string only contains invalid characters!

    • isValidPattern

      public static boolean isValidPattern(@Nonnull @RegEx String sRegEx)
      Check if the passed regular expression is invalid.
      Note: this method may be a performance killer, as it calls Pattern.compile(String) each time, which is CPU intensive and has a synchronization penalty.
      Parameters:
      sRegEx - The regular expression to validate. May not be null.
      Returns:
      true if the pattern is valid, false otherwise.

    • getAllMatchingGroupValues

      @Nullable public static String[] getAllMatchingGroupValues(@Nonnull @RegEx String sRegEx, @Nonnull String sValue)
      Get the values of all groups (RegEx (...)) for the passed value.
      Note: groups starting with "?:" are non-capturing groups (e.g. (?:a|b))
      Parameters:
      sRegEx - The regular expression containing the groups
      sValue - The value to check
      Returns:
      null if the passed value does not match the regular expression. An empty array if the regular expression contains no capturing group.