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.

@author
Michael McCloskey
@version
1.5 06/28/04
@since
1.5
See Also
Matcher
Returns the offset after the last character matched.

Return
@return The offset after the last character matched
Throws
IllegalStateException If no match has yet been attempted, or if the previous match operation failed
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
Return
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
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.

Return
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
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
Return
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
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.

Return
The number of capturing groups in this matcher's pattern
Returns the start index of the match.
Return
The index of the first character matched
Throws
IllegalStateException If no match has yet been attempted, or if the previous match operation failed
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
Return
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