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| <html> |
| |
| <head> |
| <meta http-equiv="Content-Language" content="en-us"> |
| <link rel="stylesheet" type="text/css" href="../stylesheets/style.css"> |
| <title>Regexp Type</title> |
| </head> |
| |
| <body> |
| |
| <h2><a name="regexp">Regexp</a></h2> |
| <p> |
| Regexp represents a regular expression. |
| <h3>Parameters</h3> |
| <table border="1" cellpadding="2" cellspacing="0"> |
| <tr> |
| <td valign="top"><b>Attribute</b></td> |
| <td valign="top"><b>Description</b></td> |
| <td align="center" valign="top"><b>Required</b></td> |
| </tr> |
| <tr> |
| <td valign="top">pattern</td> |
| <td valign="top">regular expression pattern</td> |
| <td valign="top" align="center">Yes</td> |
| </tr> |
| </table> |
| |
| <h3>Examples</h3> |
| <blockquote><pre> |
| <regexp id="myregexp" pattern="alpha(.+)beta"/><br> |
| </pre></blockquote> |
| <p> |
| Defines a regular expression for later use with id myregexp. |
| </p> |
| <blockquote><pre> |
| <regexp refid="myregexp"/><br> |
| </pre></blockquote> |
| <p> |
| Use the regular expression with id myregexp. |
| </p> |
| <h3><a name="implementation">Choice of regular expression implementation</a></h3> |
| <p> |
| Ant comes with |
| wrappers for |
| <a href="http://java.sun.com/j2se/1.4/docs/api/java/util/regex/package-summary.html" target="_top">the java.util.regex package of JDK 1.4</a>, |
| <a href="http://jakarta.apache.org/regexp/" target="_top">jakarta-regexp</a> |
| and <a href="http://jakarta.apache.org/oro/" 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 : |
| <ul> |
| <li> |
| org.apache.tools.ant.util.regexp.Jdk14RegexpRegexp |
| </li> |
| <li> |
| org.apache.tools.ant.util.regexp.JakartaOroRegexp |
| </li> |
| <li> |
| org.apache.tools.ant.util.regexp.JakartaRegexpRegexp |
| </li> |
| </ul> |
| It can also be another implementation of the interface <code>org.apache.tools.ant.util.regexp.Regexp</code>. |
| If <code>ant.regexp.regexpimpl</code> is not defined, ant checks in the order Jdk14Regexp, JakartaOroRegexp, |
| JakartaRegexp for the availability of the corresponding library. The first of these 3 which is found will be used.</p> |
| <p> |
| 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. |
| <ul> |
| <li>Jakarta Oro defines a line terminator as '\n' and is consistent with Perl.</li> |
| <li>Jakarta RegExp uses a system-dependant line terminator.</li> |
| <li>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)</li> |
| </ul> |
| <em>We <b>strongly</b> recommend that you use Jakarta Oro.</em> |
| </p> |
| <h3>Usage</h3> |
| The following tasks and types use the Regexp type : |
| <ul> |
| <li><a href="../OptionalTasks/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> |
| </ul> |
| |
| </body> |
| </html> |
