Conditions

Conditions are nested elements of the <condition> and <waitfor> tasks. There are core conditions and custom conditions. Custom conditions are described in Custom Conditions. Core Conditions are described below.

Core Conditions

These are the nested elements that can be used as conditions in the <condition> and <waitfor> tasks.

not

The <not> 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.

and

The <and> 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.

The <and> 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.

or

The <or> 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.

The <or> 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.

xor

The <xor> element performs an exclusive or on all nested elements, similar to the ^ operator in Java. It only evaluates to true if an odd number of nested conditions are true. There is no shortcutting of evaluation, unlike the <and> and <or> tests. It doesn't have any attributes and accepts all nested elements of the condition task as nested elements as well.

available

This condition is identical to the Available task, all attributes and nested elements of that task are supported, the property and value attributes are redundant and will be ignored.

uptodate

This condition is identical to the Uptodate task, all attributes and nested elements of that task are supported, the property and value attributes are redundant and will be ignored.

os

Test whether the current operating system is of a given type. Each defined attribute is tested and the result is true only if all the tests succeed.

Supported values for the family attribute are:

• windows—for all versions of Microsoft Windows
• dos—for all Microsoft DOS based operating systems including Microsoft Windows and OS/2
• mac—for all Apple Macintosh systems prior to Mac OS X
• unix—for all Unix(-like) operating systems, including Linux and Mac OS X/macOS
• netware—for Novell NetWare
• os/2—for OS/2
• tandem—for HP's NonStop Kernel, formerly Tandem
• win9x—for Microsoft Windows 95 and 98, ME and CE
• winnt—for Microsoft Windows NT-based systems, including Windows 2000, XP and successors
• z/os—for z/OS and OS/390
• os/400—for OS/400
• openvms—for OpenVMS

equals

Tests whether the two given values are equal.

isset

Test whether a given property has been set in this project.

checksum

This condition is identical to the Checksum task, all attributes and nested elements of that task are supported, the property and overwrite attributes are redundant and will be ignored.

http

The http condition checks for a valid response from a web server of the specified URL. By default, HTTP responses errors of 400 or greater are viewed as invalid.

socket

The socket condition checks for the existence of a TCP/IP listener at the specified host and port.

filesmatch

Test two files for matching. Nonexistence of one file results in false, although if neither exists they are considered equal in terms of content. This test does a byte for byte comparison, so test time scales with byte size. Note: if the files are different sizes, one of them is missing or the filenames match the answer is so obvious the detailed test is omitted.

contains

Tests whether a string contains another one.

istrue

Tests whether a string equals any of the Ant definitions of true, that is true, yes, or on

<istrue value="${someproperty}"/>
<istrue value="false"/>

isfalse

Tests whether a string is not true, the negation of <istrue>

<isfalse value="${someproperty}"/>
<isfalse value="false"/>

isreference

Test whether a given reference has been defined in this project and—optionally—is of an expected type.

Since Apache Ant 1.6.

issigned

Test whether a jarfile is signed. If the name of the signature is passed, the file is checked for presence of that particular signature; otherwise the file is checked for the existence of any signature. It does not perform rigorous signature validation; it only looks for the presence of a signature.

Since Apache Ant 1.7.

isfileselected

Test whether a file passes an embedded selector.

Since Apache Ant 1.6.3.

Example usage:

<isfileselected file="a.xml">
  <date datetime="06/28/2000 2:02 pm" when="equal"/>
</isfileselected>

typefound

Test whether a given type is defined, and that its implementation class can be loaded. Types include tasks, datatypes, scriptdefs, macrodefs and presetdefs.

Since Apache Ant 1.7.

Example usages:

<typefound name="junit"/>
<typefound uri="antlib:org.apache.maven.artifact.ant" name="artifact"/>

scriptcondition

Evaluate a condition based on a script in any Apache BSF or JSR 223 supported language.

See the Script task for an explanation of scripts and dependencies.

Since Apache Ant 1.7.

Parameters specified as nested elements

classpath

See the script task for using this nested element.

Description

The script supports script language inline, this script has access to the same beans as the <script> task, and to the self bean, which refers back to the condition itself. If the script evaluates to a boolean result, this is the result of the condition's evaluation (since Ant 1.7.1). Alternatively, self.value can be used to set the evaluation result.

Example:

<scriptcondition language="javascript"
        value="true">
    self.setValue(false);
</scriptcondition>

Sets the default value of the condition to true, then in the script, sets the value to false. This condition always evaluates to false.

parsersupports

Tests whether Ant's XML parser supports a given feature or property, as per the SAX/JAXP specifications, by attempting to set the appropriate property/feature

Since Apache Ant 1.7.

<parsersupports feature="http://xml.org/sax/features/namespaces"/>

Check for namespace support. All SAX2 parsers should have this.

<or>
  <parsersupports
    feature="http://apache.org/xml/features/validation/schema"/>
  <parsersupports
    feature="http://java.sun.com/xml/jaxp/properties/schemaSource"/>
</or>

Check for XML Schema support.

<parsersupports
  property="http://apache.org/xml/properties/schema/external-noNamespaceSchemaLocation"
  value="document.xsd"/>

Check for Xerces-specific definition of the location of the no namespace schema.

isreachable

Uses Java 5+ networking APIs to probe for a (remote) system being reachable. Exactly what probe mechanisms are used is an implementation feature of the JVM. They may include ICMP "ping" packets, UDP or TCP connections to port 7 "echo service" or other means.

This condition turns unknown host exceptions into false conditions. This is because on a laptop, DNS is one of the first services when the network goes; you are implicitly offline.

If a URL is supplied instead of a host, the hostname is extracted and used in the test—all other parts of the URL are discarded.

The test may not work through firewalls, that is, something may be reachable using a protocol such as HTTP, while the lower level ICMP packets get dropped on the floor. Similarly, a host may detected as reachable with ICMP, but not reachable on other ports (i.e. port 80), because of firewalls.

Since Apache Ant 1.7.

<condition property="offline">
  <isreachable url="https://ibiblio.org/maven/"/>
</condition>

Probe for the Maven repository being reachable.

<condition property="offline">
  <isreachable host="ibiblio.org" timeout="10"/>
</condition>

Probe for the Maven repository being reachable using the hostname, ten second timeout.

length

Since Ant 1.6.3

This condition is a facet of the Length task. It is used to test the length of a string or one or more files.

<length string=" foo " trim="true" length="3"/>

Verify a string is of a certain length.

<length file="foo" when="greater" length="0"/>

Verify that file foo is not empty.

isfailure

Since Ant 1.7

Test the return code of an executable (see the Exec task) for failure.

resourcecount

Since Ant 1.7

This condition is a facet of the ResourceCount task. It is used to test the size of a resource collection.

<resourcecount refid="myresourcecollection" when="greater" count="0"/>

Verify that a resource collection is not empty.

resourcesmatch

Since Ant 1.7

Test resources for matching. Nonexistence of one or more resources results in false, although if none exists they are considered equal in terms of content. By default, this test does a byte for byte comparison, so test time scales with byte size. Note: if the files are different sizes, one of them is missing or the filenames match the answer is so obvious the detailed test is omitted. The resources to check are specified as nested resource collections, meaning that more than two resources can be checked; in this case all resources must match.

resourcecontains

Since Ant 1.7.1

Tests whether a resource contains a given (sub)string.

The resources to check are specified via references or—in the case of file resources—via the resource attribute.

hasmethod

Since Ant 1.7

Tests for a class having a method or field. If the class is not found or fails to load, the build fails.

There is also a nested <classpath> element, which can be used to specify a classpath.

<hasmethod classname="java.util.ArrayList" method="trimToSize"/>

Looks for the method trimToSize() in the java.util.ArrayList class.

matches

Since Ant 1.7

Test if the specified string matches the specified regular expression pattern

There is also an optional <regexp> element, which can be used to specify a regular expression instead of the pattern attribute. See Regexp Type for the description of the nested element regexp and of the choice of regular expression implementation.

An example:

<condition property="legal-password">
  <matches pattern="[1-9]" string="${user-input}"/>
</condition>
<fail message="Your password should at least contain one number"
      unless="legal-password"/>

The following example sets the property ok if the property input is three characters long, starting with a and ending with b.

<condition property="ok">
  <matches string="${input}" pattern="^a.b$"/>
</condition>

The following defines a reference regular expression for matching dates and then uses antunit to check if the property today is in the correct format:

<regexp id="date.pattern" pattern="^[0123]\d-[01]\d-[12]\d\d\d$"/>

<au:assertTrue xmlns:au="antlib:org.apache.ant.antunit">
  <matches string="${today}">
    <regexp refid="date.pattern"/>
  </matches>
</au:assertTrue>

The following example shows the use of the singleline and the casesensitive flags.

<au:assertTrue>
  <matches string="AB${line.separator}C" pattern="^ab.*C$"
           casesensitive="false"
           singleline="true"/>
</au:assertTrue>
<au:assertFalse>
  <matches string="AB${line.separator}C" pattern="^ab.*C$"
           casesensitive="false"
           singleline="false"/>
</au:assertFalse>

antversion

This condition is identical to the Antversion task, all attributes are supported, the property attribute is redundant and will be ignored.

hasfreespace

Since Ant 1.7.0

Tests a partition to see if there is enough space.

Needed attribute can be specified using standard computing terms:

• K : Kilobytes (1024 bytes)
• M : Megabytes (1024 K)
• G : Gigabytes (1024 M)
• T : Terabytes (1024 G)
• P : Petabytes (1024 T)

An example:

<hasfreespace partition="c:" needed="100M"/>

islastmodified

Since Ant 1.8.0

Tests the last modified date of a resource.

The actual resource to test is specified as a nested element.

An example:

<islastmodified dateTime="08/18/2009 04:41:19 AM" mode="not-before">
  <file file="${file}"/>
</islastmodified>

resourceexists

Since Ant 1.8.0

Tests a resource for existence.

The actual resource to test is specified as a nested element.

An example:

<resourceexists>
  <file file="${file}"/>
</resourceexists>

javaversion

Since Ant 1.10.2

Tests the version of the JVM executing Ant.

An example:

<javaversion atleast="9"/>

will evaluate to true if the current JVM is Java 9 or above.