<p>When I use the  task, the property is only set to TRUE if the resource (say file) is available. If not, the property is undefined.</p>

<p>When I print the value of the property, it gives true if the resource was available, but otherwise just prints the property name.</p>

<p>Is there a way to set the property to some value if the resource is <em>not</em> available? I have tried setting the property explicitly before the available check, but then ant complains:</p>

<pre>
[available] DEPRECATED -  used to override an existing property.
[available]   Build file should not reuse the same property name for different values.
</pre>

You can use a condition in combination with not:
http://ant.apache.org/manual/Tasks/condition.html
```
```
<condition property="fooDoesNotExist">
    <not>
      <available filepath="path/to/foo"/>
    </not>
  </condition>
```
```