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| <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><regexp id="myregexp" pattern="alpha(.+)beta"/></pre> |
| <p>Defines a regular expression for later use with <var>id</var> <q>myregexp</q>.</p> |
| <pre><regexp refid="myregexp"/></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> |
