youys
/
ant

 
			
			   
				 
					
						
						
							
							<!DOCTYPE html>
<!--
   Licensed to the Apache Software Foundation (ASF) under one or more
   contributor license agreements.  See the NOTICE file distributed with
   this work for additional information regarding copyright ownership.
   The ASF licenses this file to You under the Apache License, Version 2.0
   (the "License"); you may not use this file except in compliance with
   the License.  You may obtain a copy of the License at

       https://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
-->
<html lang="en">

<head>
<link rel="stylesheet" type="text/css" href="../stylesheets/style.css">
<title>Regexp Type</title>
</head>

<body>

<h2 id="regexp">Regexp</h2>
<p>
Regexp represents a regular expression.
<h3>Parameters</h3>
<table class="attr">
  <tr>
    <th scope="col">Attribute</th>
    <th scope="col">Description</th>
    <th scope="col">Required</th>
  </tr>
  <tr>
    <td>pattern</td>
    <td>regular expression pattern</td>
    <td>Yes</td>
  </tr>
  <tr>
    <td>refid</td>
    <td>Makes this <code>regexp</code>
      a <a href="../using.html#references">reference</a> to
      a <code>regexp</code> defined elsewhere. If specified no other
      attributes or nested elements are allowed.</td>
    <td>No</td>
  </tr>
</table>

<h3>Examples</h3>
<pre>&lt;regexp id="myregexp" pattern="alpha(.+)beta"/&gt;</pre>
<p>Defines a regular expression for later use with <var>id</var> <q>myregexp</q>.</p>
<pre>&lt;regexp refid="myregexp"/&gt;</pre>
<p>Use the regular expression with <var>id</var> <q>myregexp</q>.</p>
<h3 id="implementation">Choice of regular expression implementation</h3>
<p>Apache Ant comes with wrappers for
the <a href="https://docs.oracle.com/javase/8/docs/api/java/util/regex/package-summary.html"
target="_top">java.util.regex
package</a>, <a href="https://attic.apache.org/projects/jakarta-regexp.html"
target="_top">jakarta-regexp</a> and <a href="https://attic.apache.org/projects/jakarta-oro.html"
target="_top">jakarta-ORO</a>, see <a href="../install.html#librarydependencies">installation
dependencies</a> concerning the supporting libraries.</p>
<p>The property <code>ant.regexp.regexpimpl</code> governs which regular expression implementation
will be chosen.  Possible values for this property are:</p>
<ul>
<li><code class="code">org.apache.tools.ant.util.regexp.Jdk14RegexpRegexp</code></li>
<li><code class="code">org.apache.tools.ant.util.regexp.JakartaOroRegexp</code></li>
<li><code class="code">org.apache.tools.ant.util.regexp.JakartaRegexpRegexp</code></li>
</ul>
<p>It can also be another implementation of the
interface <code class="code">org.apache.tools.ant.util.regexp.Regexp</code>.
If <code>ant.regexp.regexpimpl</code> is not defined, Ant uses Jdk14Regexp as this is always
available.</p>
<p>
There are cross-platform issues for matches related to line terminator.  For example if you
use <q>$</q> 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 <em>highly recommended</em> that you test your pattern on both Unix and Windows platforms before
you rely on it.</p>
<ul>
  <li>Jakarta Oro defines a line terminator as <q>\n</q> and is consistent with Perl.</li>
  <li>Jakarta RegExp uses a system-dependent line terminator.</li>
  <li>JDK 1.4 uses <q>\n</q>, <q>\r\n</q>, <q>\u0085</q>, <q>\u2028</q>, <q>\u2029</q> as a
    default but is configured in the wrapper to use only <q>\n</q> (UNIX_LINE)</li>
</ul>
<p><em>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.</em></p>
<h3>Usage</h3> The following tasks and types use the Regexp type:
<ul>
<li><a href="../Tasks/replaceregexp.html">ReplaceRegExp task</a></li>
<li><a href="filterchain.html#linecontainsregexp">LineContainsRegexp filter</a></li>
</ul>
<p>These string filters also use the mechanism of regexp to choose a regular expression
implementation:</p>
<ul>
<li><a href="filterchain.html#containsregex">ContainsRegex string filter</a></li>
<li><a href="filterchain.html#replaceregex">ReplaceRegex string filter</a></li>
<li><a href="selectors.html#filenameselect">filename selector</a></li>
<li><a href="resources.html#rsel.name">name resource selector</a></li>
<li><a href="selectors.html#regexpselect">containsregexp selector</a></li>
</ul>

</body>
</html>