trunk/proposal/xdocs/src/org/apache/tools/ant/taskdefs/ConditionTask.xml

<!-- Condition task -->
<external>
<description>

<p>Sets a property if a certain condition holds true - this is a
generalization of <a href="available.html">Available</a> and <a
href="uptodate.html">Uptodate</a>.</p>
<p>If the condition holds true, the property value is set to true by
default; otherwise, the property is not set. You can set the value to
something other than the default by specifying the <code>value</code>
attribute.</p>
<p>Conditions are specified as <a href="#nested">nested elements</a>,
you must specify exactly one condition.</p>

</description>

<section anchor="examples" name="Examples">

<pre>
  &lt;condition property=&quot;javamail.complete&quot;&gt;
    &lt;and&gt;
      &lt;available classname=&quot;javax.activation.DataHandler&quot; /&gt;
      &lt;available classname=&quot;javax.mail.Transport&quot; /&gt;
    &lt;/and&gt;
  &lt;/condition&gt;
</pre>
<p>sets the property <code>javamail.complete</code> if both the
JavaBeans Activation Framework and JavaMail are available in the
classpath.</p>

<pre>
  &lt;condition property=&quot;isMacOsButNotMacOsX&quot;&gt;
    &lt;and&gt;
      &lt;os family=&quot;mac&quot; />
      &lt;not&gt;
        &lt;os family=&quot;unix&quot; />
      &lt;/not&gt;
    &lt;/and&gt;
  &lt;/condition&gt;
</pre>
<p>sets the property <code>isMacOsButNotMacOsX</code> if the current
operating system is MacOS, but not MacOS X - which Ant considers to be
in the Unix family as well.</p>

<pre>
  &lt;condition property=&quot;isSunOSonSparc&quot;&gt;
    &lt;os name=&quot;SunOS&quot; arch=&quot;sparc&quot; />
  &lt;/condition&gt;
</pre>
<p>sets the property <code>isSunOSonSparc</code> if the current
operating system is SunOS and if it is running on a sparc architecture.</p>

</section>
</external>