java.util.regex.MatchResult Maven / Gradle / Ivy
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package java.util.regex;
/**
* 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
* @see Matcher
* @since 1.5
*/
public interface MatchResult {
/**
* 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
*/
public int start();
/**
* 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().
*
* @param 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
*
* @throws IndexOutOfBoundsException
* If there is no capturing group in the pattern
* with the given index
*/
public int start(int group);
/**
* 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
*/
public int end();
/**
* 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().
*
* @param 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
*
* @throws IndexOutOfBoundsException
* If there is no capturing group in the pattern
* with the given index
*/
public int end(int 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.
*
* @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
*/
public String 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.
*
* @param 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
*
* @throws IndexOutOfBoundsException
* If there is no capturing group in the pattern
* with the given index
*/
public String group(int group);
/**
* 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
*/
public int groupCount();
}