Regexp
Regexp represents a regular expression.
Parameters
Attribute Description Required pattern regular expression pattern Yes Examples
<regexp id="myregexp" pattern="alpha(.+)beta"/>
Defines a regular expression for later use with id myregexp.
<regexp refid="myregexp"/>
Use the regular expression with id myregexp.
Choice of regular expression implementation
Apache Ant comes with wrappers for the java.util.regex package, jakarta-regexp and jakarta-ORO, See installation dependencies concerning the supporting libraries.
The property
ant.regexp.regexpimplgoverns which regular expression implementation will be chosen. Possible values for this property are :It can also be another implementation of the interface
- org.apache.tools.ant.util.regexp.Jdk14RegexpRegexp
- org.apache.tools.ant.util.regexp.JakartaOroRegexp
- org.apache.tools.ant.util.regexp.JakartaRegexpRegexp
org.apache.tools.ant.util.regexp.Regexp. Ifant.regexp.regexpimplis not defined, Ant uses Jdk14Regexp as this is always available.There are cross-platform issues for matches related to line terminator. For example if you use $ to anchor your regular expression on the end of a line the results might be very different depending on both your platform and the regular expression library you use. It is 'highly recommended' that you test your pattern on both Unix and Windows platforms before you rely on it.
We used to recommend that you use Jakarta ORO but since its development has been retired Java's built-in regex package is likely the best choice going forward.
- Jakarta Oro defines a line terminator as '\n' and is consistent with Perl.
- Jakarta RegExp uses a system-dependent line terminator.
- JDK 1.4 uses '\n', '\r\n', '\u0085', '\u2028', '\u2029' as a default but is configured in the wrapper to use only '\n' (UNIX_LINE)
Usage
The following tasks and types use the Regexp type :These string filters also use the mechanism of regexp to choose a regular expression implementation :