## Condition

### Description

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.

### Parameters

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.

### Examples

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

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

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

          <not>
            <os family="unix"/>

          </not>
        </and>
      </condition>

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"/>

      </condition>

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