Sets a property if a certain condition holds true - this is a generalization of Available and Uptodate.

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 value attribute.

Conditions are specified as nested elements, you must specify exactly one condition.


Attribute Description Required
property The name of the property to set. Yes
value The value to set the property to. Defaults to "true". No
else The value to set the property to if the condition evaluates to false. By default the property will remain unset. Since Apache Ant 1.6.3 No

Parameters specified as nested elements

All conditions to test are specified as nested elements, for a complete list see here.


  <condition property="javamail.complete">
      <available classname="javax.activation.DataHandler"/>
      <available classname="javax.mail.Transport"/>

sets the property javamail.complete if both the JavaBeans Activation Framework and JavaMail are available in the classpath.

  <condition property="isMacOsButNotMacOsX">
      <os family="mac"/>

        <os family="unix"/>


sets the property isMacOsButNotMacOsX if the current operating system is MacOS, but not MacOS X - which Ant considers to be in the Unix family as well.

  <condition property="isSunOSonSparc">
    <os name="SunOS" arch="sparc"/>


sets the property isSunOSonSparc if the current operating system is SunOS and if it is running on a sparc architecture.