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This trail teaches the regular expression syntax supported by the
java.util.regex API and presents several working examples to illustrate
how the various objects interact.
In the world of regular expressions, there are
many different flavors to choose from, such as
grep, Perl, Tcl, Python, PHP, and awk. The regular expression syntax in
the java.util.regex API is most similar to that found in Perl.
java.util.regex package primarily consists of three classes:
Pattern,
Matcher, and
PatternSyntaxException.
Pattern object is a compiled representation of a regular expression.
The Pattern class provides no public constructors.
To create a pattern, you must first invoke one of its public static
compile methods, which will then return a Pattern object. These methods accept a regular expression as the first argument;
the first few lessons of this trail will teach you the required syntax.
Matcher object is the engine that interprets the
pattern and performs match operations against an input string.
Like the Pattern class, Matcher defines no public constructors. You obtain a Matcher object by invoking
the matcher method on a Pattern object.
PatternSyntaxException object is an unchecked exception that indicates a syntax error in a regular expression pattern.
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