Scriptdef can be used to define an Ant task using a scripting language. Ant +scripting languages supported by +Apache BSF 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. +
+ +Note: This task depends on external libraries not included in the +Ant distribution. See +Library Dependencies +for more information.
+ +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 attributes and elements. The
+elements in the attributes collection may be accessed by the
+attribute name. The elements 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.
+
The name "project" is a pre-defined reference to the Ant Project. For +more information on writing scripts, please refer to the +<script> task +
+ +| Attribute | +Description | +Required | +
| name | +the name of the task to be created using the script | +Yes | +
| language | +The programming language the script is written in. + Must be a supported Apache BSF language | +Yes | +
| src | +The location of the script as a file, if not inline | +No | +
| Attribute | +Description | +Required | +
| name | +the name of the attribute | +Yes | +
| Attribute | +Description | +Required | +
| name | +the name of the nested element to be supported by the + task defined by the script | +Yes | +
| classname | +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. | +No | +
| type | +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 | +No | +
+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. +
+ +
+ <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>
+
+
++The following variation on the above script lists the number of fileset elements +and iterates through them +
+
+ <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>
+
+
++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 +
+ +build.xml:15: SyntaxError: missing } in compound
+statement (scriptdef <scripttest2>; line 10)
+Script errors are only detected when a script task is actually executed. +
+ + +Copyright © 2000-2003 Apache Software Foundation. All rights +Reserved.
+ + + \ No newline at end of file