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| <head> |
| <meta http-equiv="Content-Language" content="en-us"> |
| <title>Scriptdef Task</title> |
| <link rel="stylesheet" type="text/css" href="../stylesheets/antmanual.css"> |
| </head> |
| |
| <body> |
| |
| <h2><a name="script">Script</a></h2> |
| <h3>Description</h3> |
| <p>Scriptdef can be used to define an Ant task using a scripting language. Ant |
| scripting languages supported by |
| <a href="http://jakarta.apache.org/bsf" target="_top">Apache BSF</a> may be |
| used to define the script. Scriptdef provides a mechanism to encapsulate |
| control logic from a build within an Ant task minimizing the need for |
| proviuding control style tasks in Ant itself. Complex logic can be made |
| available while retaining the simple structure of an Ant build file. Scriptdef |
| is also useful for prototyping new custom tasks. Certainly as the complexity |
| of the script increases it would be better to migrate the task definition |
| into a Java based custom task. |
| </p> |
| |
| <p><b>Note:</b> This task depends on external libraries not included in the |
| Ant distribution. See |
| <a href="../install.html#librarydependencies">Library Dependencies</a> |
| for more information.</p> |
| |
| <p>The attributes and nested elements supported by the task may be defined |
| using <attribute> and <element> nested elements. These are |
| available to the script that implements the task as two collection style |
| script variables <code>attributes</code> and <code>elements</code>. The |
| elements in the <code>attributes</code> collection may be accessed by the |
| attribute name. The <code>elements</code> collection is accessed by the nested |
| element name. This will return a list of all instances of the nested element. |
| The instances in this list may be accessed by an integer index. |
| </p> |
| |
| <p>The name "project" is a pre-defined reference to the Ant Project. For |
| more information on writing scripts, please refer to the |
| <a href="script.html"><script></a> task |
| </p> |
| |
| <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">name</td> |
| <td valign="top">the name of the task to be created using the script</td> |
| <td valign="top" align="center">Yes</td> |
| </tr> |
| <tr> |
| <td valign="top">language</td> |
| <td valign="top">The programming language the script is written in. |
| Must be a supported Apache BSF language</td> |
| <td valign="top" align="center">Yes</td> |
| </tr> |
| <tr> |
| <td valign="top">src</td> |
| <td valign="top">The location of the script as a file, if not inline</td> |
| <td valign="top" align="center">No</td> |
| </tr> |
| </table> |
| |
| <h3>Nested elements</h3> |
| <h4>attribute</h4> |
| <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">name</td> |
| <td valign="top">the name of the attribute</td> |
| <td valign="top" align="center">Yes</td> |
| </tr> |
| </table> |
| |
| <h4>element</h4> |
| <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">name</td> |
| <td valign="top">the name of the nested element to be supported by the |
| task defined by the script</td> |
| <td valign="top" align="center">Yes</td> |
| </tr> |
| <tr> |
| <td valign="top">classname</td> |
| <td valign="top">the classname of the class to be used for the nested element. |
| This specifies the class directly and is an alternative to specifying |
| the Ant type name.</td> |
| <td valign="top" align="center">No</td> |
| </tr> |
| <tr> |
| <td valign="top">type</td> |
| <td valign="top">This is the name of an Ant task or type which is to |
| be used when this element is to be created. This is an alternative |
| to specifying the class name directly</td> |
| <td valign="top" align="center">No</td> |
| </tr> |
| </table> |
| |
| |
| |
| <h3>Examples</h3> |
| |
| <p> |
| The following definition creates a task which supprts an attribute called |
| attr and two nested elements, one being a fileset and the other a path. When |
| executed, the resulting task logs the value of the attribute and the basedir |
| of the first fileset. |
| </p> |
| |
| <pre> |
| <scriptdef name="scripttest" language="javascript"> |
| <attribute name="attr1"/> |
| <element name="fileset" type="fileset"/> |
| <element name="path" type="path"/> |
| <![CDATA[ |
| |
| project.log("Hello from script"); |
| project.log("Attribute attr1 = " + attributes.get("attr1")); |
| project.log("First fileset basedir = " |
| + elements.get("fileset").get(0).getDir(project)); |
| |
| ]]> |
| </scriptdef> |
| |
| <scripttest attr1="test"> |
| <path> |
| <pathelement location="src"/> |
| </path> |
| <fileset dir="src"/> |
| <fileset dir="main"/> |
| </scripttest> |
| </pre> |
| |
| <p> |
| The following variation on the above script lists the number of fileset elements |
| and iterates through them |
| </p> |
| <pre> |
| <scriptdef name="scripttest2" language="javascript"> |
| <element name="fileset" type="fileset"/> |
| <![CDATA[ |
| filesets = elements.get("fileset"); |
| project.log("Number of filesets = " + filesets.size()); |
| for (i = 0; i < filesets.size(); ++i) { |
| project.log("fileset " + i + " basedir = " |
| + filesets.get(i).getDir(project)); |
| } |
| ]]> |
| </scriptdef> |
| |
| <scripttest2> |
| <fileset dir="src"/> |
| <fileset dir="main"/> |
| </scripttest2> |
| </pre> |
| |
| <p> |
| When a script has a syntax error, the scriptdef name will be listed in the |
| error. For example in the above script, removing the closing curly bracket |
| would result in this error |
| </p> |
| |
| <p><code>build.xml:15: SyntaxError: missing } in compound |
| statement (scriptdef <scripttest2>; line 10)</code></p> |
| |
| <p> |
| Script errors are only detected when a script task is actually executed. |
| </p> |
| |
| |
| <hr> |
| <p align="center">Copyright © 2000-2003 Apache Software Foundation. All rights |
| Reserved.</p> |
| |
| </body> |
| </html> |
