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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 Also:
Since:1.5
/**
 * The result of a match operation.
 *
 * <p>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 {@code MatchResult}.
 *
 * @author  Michael McCloskey
 * @see Matcher
 * @since 1.5
 */
public interface MatchResult {

    
Returns the start index of the match.

Throws:
Returns: The index of the first character matched
/**
     * 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(). 


Params:
  • group – 
        The index of a capturing group in this matcher's pattern
Throws:
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
/**
     * Returns the start index of the subsequence captured by the given group
     * during this match.
     *
     * <p> <a href="Pattern.html#cg">Capturing groups</a> are indexed from left
     * to right, starting at one.  Group zero denotes the entire pattern, so
     * the expression <i>m.</i>{@code start(0)} is equivalent to
     * <i>m.</i>{@code start()}.  </p>
     *
     * @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 {@code -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.

Throws:
Returns: The offset after the last character matched
/**
     * Returns the offset after the last character matched.
     *
     * @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(). 


Params:
  • group – 
        The index of a capturing group in this matcher's pattern
Throws:
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
/**
     * Returns the offset after the last character of the subsequence
     * captured by the given group during this match.
     *
     * <p> <a href="Pattern.html#cg">Capturing groups</a> are indexed from left
     * to right, starting at one.  Group zero denotes the entire pattern, so
     * the expression <i>m.</i>{@code end(0)} is equivalent to
     * <i>m.</i>{@code end()}.  </p>
     *
     * @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 {@code -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. 


Throws:
Returns:The (possibly empty) subsequence matched by the previous match,
        in string form
/**
     * Returns the input subsequence matched by the previous match.
     *
     * <p> For a matcher <i>m</i> with input sequence <i>s</i>,
     * the expressions <i>m.</i>{@code group()} and
     * <i>s.</i>{@code substring(}<i>m.</i>{@code start(),}&nbsp;<i>m.</i>{@code end())}
     * are equivalent.  </p>
     *
     * <p> Note that some patterns, for example {@code a*}, match the empty
     * string.  This method will return the empty string when the pattern
     * successfully matches the empty string in the input.  </p>
     *
     * @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. 


Params:
  • group – 
        The index of a capturing group in this matcher's pattern
Throws:
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
/**
     * Returns the input subsequence captured by the given group during the
     * previous match operation.
     *
     * <p> For a matcher <i>m</i>, input sequence <i>s</i>, and group index
     * <i>g</i>, the expressions <i>m.</i>{@code group(}<i>g</i>{@code )} and
     * <i>s.</i>{@code substring(}<i>m.</i>{@code start(}<i>g</i>{@code
     * ),}&nbsp;<i>m.</i>{@code end(}<i>g</i>{@code ))}
     * are equivalent.  </p>
     *
     * <p> <a href="Pattern.html#cg">Capturing groups</a> are indexed from left
     * to right, starting at one.  Group zero denotes the entire pattern, so
     * the expression {@code m.group(0)} is equivalent to {@code m.group()}.
     * </p>
     *
     * <p> If the match was successful but the group specified failed to match
     * any part of the input sequence, then {@code null} is returned. Note
     * that some groups, for example {@code (a*)}, match the empty string.
     * This method will return the empty string when such a group successfully
     * matches the empty string in the input.  </p>
     *
     * @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 {@code 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.  


Returns:The number of capturing groups in this matcher's pattern
/**
     * Returns the number of capturing groups in this match result's pattern.
     *
     * <p> Group zero denotes the entire pattern by convention. It is not
     * included in this count.
     *
     * <p> 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.  </p>
     *
     * @return The number of capturing groups in this matcher's pattern
     */
    public int groupCount();

}