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<h2><a name="Condition">Condition</a></h2>
<h3>Description</h3>
<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>
<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">property</td>
<td valign="top">The name of the property to set.</td>
<td valign="top" align="center">Yes</td>
</tr>
<tr>
<td valign="top">value</td>
<td valign="top">The value to set the property to. Defaults to
"true".</td>
<td valign="top" align="center">No</td>
</tr>
</table>
<h3><a name="nested">Parameters specified as nested elements</a></h3>
<p>All conditions to test are specified as nested elements.</p>
<h4>not</h4>
<p>The <code><not></code> element expects exactly one other
condition to be nested into this element, negating the result of the
condition. It doesn't have any attributes and accepts all nested
elements of the condition task as nested elements as well.</p>
<h4>and</h4> <p>
The <code><and></code> element doesn't have any attributes and
accepts an arbitrary number of conditions as nested elements - all
nested elements of the condition task are supported. This condition
is true if all of its contained conditions are, conditions will be
evaluated in the order they have been specified in the build file.</p>
<p>The <code><and></code> condition has the same shortcut
semantics as the Java && operator, as soon as one of the
nested conditions is false, no other condition will be evaluated.</p>
<h4>or</h4> <p>
The <code><or></code> element doesn't have any attributes and
accepts an arbitrary number of conditions as nested elements - all
nested elements of the condition task are supported. This condition
is true if at least one of its contained conditions is, conditions
will be evaluated in the order they have been specified in the build
file.</p> <p>The <code><or></code> condition has the same
shortcut semantics as the Java || operator, as soon as one of the
nested conditions is true, no other condition will be evaluated.</p>
<h4>available</h4>
<p>This condition is identical to the <a
href="available.html">Available</a> task, all attributes and nested
elements of that task are supported, the property and value attributes
are redundant and will be ignored.</p>
<h4>uptodate</h4>
<p>This condition is identical to the <a
href="uptodate.html">Uptodate</a> task, all attributes and nested
elements of that task are supported, the property and value attributes
are redundant and will be ignored.</p>
<h4>os</h4>
<p>Test whether the current operating system is of a given type.</p>
<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">family</td>
<td valign="top">The name of the operating system family to expect.</td>
<td valign="top" align="center">No</td>
</tr>
</table>
<p>Supported values for the family attribute are:
<ul>
<li>windows (for all versions of Microsoft Windows)</li>
<li>dos (for all Microsoft DOS based operating systems including
Microsoft Windows and OS/2)</li>
<li>mac (for all Apple Macintosh systems)</li>
<li>unix (for all Unix and Unix-like operating systems)</li>
<li>netware (for Novell NetWare)</li>
<li>os/2 (for OS/2)</li>
</ul>
<h4>equals</h4>
<p>Tests whether the two given Strings are identical</p>
<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">arg1</td>
<td valign="top">First string to test.</td>
<td valign="top" align="center">Yes</td>
</tr>
<tr>
<td valign="top">arg2</td>
<td valign="top">Second string to test.</td>
<td valign="top" align="center">Yes</td>
</tr>
</table>
<h4>isset</h4>
<p>Test whether a given property has been set in this project.</p>
<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">property</td>
<td valign="top">The name of the property to test.</td>
<td valign="top" align="center">Yes</td>
</tr>
</table>
<h4>checksum</h4>
<p>This condition is identical to the <a
href="checksum.html">Checksum</a> task, all attributes and nested
elements of that task are supported, the property and overwrite
attributes are redundant and will be ignored.</p>
<h3>Examples</h3>
<pre>
<condition property="javamail.complete">
<and>
<available classname="javax.activation.DataHandler" />
<available classname="javax.mail.Transport" />
</and>
</condition>
</pre>
<p>sets the property <code>javamail.complete</code> if both the
JavaBeans Activation Framework and JavaMail are available in the
classpath.</p>
<pre>
<condition property="isMacOsButNotMacOsX">
<and>
<os family="mac" />
<not>
<os family="unix" />
</not>
</and>
</condition>
</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>
<hr>
<p align="center">Copyright © 2001 Apache Software
Foundation. All rights Reserved.</p>
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