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
.
Matcher
int start()
Returns the start index of the match.
IllegalStateException
- If no match has yet been attempted, or if the previous match operation failedint 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()
.
group
- The index of a capturing group in this matcher's pattern-1
if the match was successful but the group itself did not match anythingIllegalStateException
- If no match has yet been attempted, or if the previous match operation failedIndexOutOfBoundsException
- If there is no capturing group in the pattern with the given indexint end()
Returns the offset after the last character matched.
IllegalStateException
- If no match has yet been attempted, or if the previous match operation failedint 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()
.
group
- The index of a capturing group in this matcher's pattern-1
if the match was successful but the group itself did not match anythingIllegalStateException
- If no match has yet been attempted, or if the previous match operation failedIndexOutOfBoundsException
- If there is no capturing group in the pattern with the given indexString 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.
IllegalStateException
- If no match has yet been attempted, or if the previous match operation failedString 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.
group
- The index of a capturing group in this matcher's patternnull
if the group failed to match part of the inputIllegalStateException
- If no match has yet been attempted, or if the previous match operation failedIndexOutOfBoundsException
- If there is no capturing group in the pattern with the given indexint 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.
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