} by interpreting a {@link Pattern}. A matcher is created from a pattern by invoking the pattern's {@link Pattern#matcher matcher} method. Once created, a matcher can be usedto perform three different kinds of match operations:
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The {@link #matches matches} method attempts to match the entire inputsequence against the pattern.
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The {@link #lookingAt lookingAt} method attempts to match the input sequence,starting at the beginning, against the pattern.
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The {@link #find find} method scans the input sequence looking for the nextsubsequence that matches the pattern.
Each of these methods returns a boolean indicating success or failure. More information about a successful match can be obtained by querying the state of the matcher.
A matcher finds matches in a subset of its input called the region. By default, the region contains all of the matcher's input. The region can be modified via the {@link #region region} method and queried via the{@link #regionStart regionStart} and {@link #regionEnd regionEnd} methods.The way that the region boundaries interact with some pattern constructs can be changed. See {@link #useAnchoringBounds useAnchoringBounds} and{@link #useTransparentBounds useTransparentBounds} for more details.
This class also defines methods for replacing matched subsequences with new strings whose contents can, if desired, be computed from the match result. The {@link #appendReplacement appendReplacement} and {@link #appendTail appendTail} methods can be used in tandem in order to collect the result intoan existing string buffer, or the more convenient {@link #replaceAll replaceAll} method can be used to create a string in which every matchingsubsequence in the input sequence is replaced.
The explicit state of a matcher includes the start and end indices of the most recent successful match. It also includes the start and end indices of the input subsequence captured by each capturing group in the pattern as well as a total count of such subsequences. As a convenience, methods are also provided for returning these captured subsequences in string form.
The explicit state of a matcher is initially undefined; attempting to query any part of it before a successful match will cause an {@link IllegalStateException} to be thrown. The explicit state of a matcheris recomputed by every match operation.
The implicit state of a matcher includes the input character sequence as well as the append position, which is initially zero and is updated by the {@link #appendReplacement appendReplacement} method.
A matcher may be reset explicitly by invoking its {@link #reset()} method or,if a new input sequence is desired, its {@link #reset(java.lang.CharSequence) reset(CharSequence)} method. Resettinga matcher discards its explicit state information and sets the append position to zero.
Instances of this class are not safe for use by multiple concurrent threads.
@author Mike McCloskey
@author Mark Reinhold
@author JSR-51 Expert Group
@version 1.64, 06/04/07
@since 1.4
@spec JSR-51
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