Module java.base
Package java.util.regex

Interface MatchResult

  • All Known Implementing Classes:
    Matcher

    public interface MatchResult
    The result of a match operation.

    This interface contains query methods used to determine the results of a match against a regular expression. The match boundaries, groups and group boundaries can be seen but not modified through a MatchResult.

    Since:
    1.5
    See Also:
    Matcher

    • Method Summary

      All Methods Instance Methods Abstract Methods 
      Modifier and Type Method Description
      int end​()
      Returns the offset after the last character matched.
      int end​(int group)
      Returns the offset after the last character of the subsequence captured by the given group during this match.
      String group​()
      Returns the input subsequence matched by the previous match.
      String group​(int group)
      Returns the input subsequence captured by the given group during the previous match operation.
      int groupCount​()
      Returns the number of capturing groups in this match result's pattern.
      int start​()
      Returns the start index of the match.
      int start​(int group)
      Returns the start index of the subsequence captured by the given group during this match.

    • Method Detail

      • start

        int start​()
        Returns the start index of the match.
        Returns:
        The index of the first character matched
        Throws:
        IllegalStateException - If no match has yet been attempted, or if the previous match operation failed

      • start

        int start​(int group)
        Returns the start index of the subsequence captured by the given group during this match.

        Capturing groups are indexed from left to right, starting at one. Group zero denotes the entire pattern, so the expression m.start(0) is equivalent to m.start().

        Parameters:
        group - The index of a capturing group in this matcher's pattern
        Returns:
        The index of the first character captured by the group, or -1 if the match was successful but the group itself did not match anything
        Throws:
        IllegalStateException - If no match has yet been attempted, or if the previous match operation failed
        IndexOutOfBoundsException - If there is no capturing group in the pattern with the given index

      • end

        int end​()
        Returns the offset after the last character matched.
        Returns:
        The offset after the last character matched
        Throws:
        IllegalStateException - If no match has yet been attempted, or if the previous match operation failed

      • end

        int end​(int group)
        Returns the offset after the last character of the subsequence captured by the given group during this match.

        Capturing groups are indexed from left to right, starting at one. Group zero denotes the entire pattern, so the expression m.end(0) is equivalent to m.end().

        Parameters:
        group - The index of a capturing group in this matcher's pattern
        Returns:
        The offset after the last character captured by the group, or -1 if the match was successful but the group itself did not match anything
        Throws:
        IllegalStateException - If no match has yet been attempted, or if the previous match operation failed
        IndexOutOfBoundsException - If there is no capturing group in the pattern with the given index

      • group

        String group​()
        Returns the input subsequence matched by the previous match.

        For a matcher m with input sequence s, the expressions m.group() and s.substring(m.start(), m.end()) are equivalent.

        Note that some patterns, for example a*, match the empty string. This method will return the empty string when the pattern successfully matches the empty string in the input.

        Returns:
        The (possibly empty) subsequence matched by the previous match, in string form
        Throws:
        IllegalStateException - If no match has yet been attempted, or if the previous match operation failed

      • group

        String group​(int group)
        Returns the input subsequence captured by the given group during the previous match operation.

        For a matcher m, input sequence s, and group index g, the expressions m.group(g) and s.substring(m.start(g ), m.end(g)) are equivalent.

        Capturing groups are indexed from left to right, starting at one. Group zero denotes the entire pattern, so the expression m.group(0) is equivalent to m.group().

        If the match was successful but the group specified failed to match any part of the input sequence, then null is returned. Note that some groups, for example (a*), match the empty string. This method will return the empty string when such a group successfully matches the empty string in the input.

        Parameters:
        group - The index of a capturing group in this matcher's pattern
        Returns:
        The (possibly empty) subsequence captured by the group during the previous match, or null if the group failed to match part of the input
        Throws:
        IllegalStateException - If no match has yet been attempted, or if the previous match operation failed
        IndexOutOfBoundsException - If there is no capturing group in the pattern with the given index

      • groupCount

        int groupCount​()
        Returns the number of capturing groups in this match result's pattern.

        Group zero denotes the entire pattern by convention. It is not included in this count.

        Any non-negative integer smaller than or equal to the value returned by this method is guaranteed to be a valid group index for this matcher.

        Returns:
        The number of capturing groups in this matcher's pattern