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.

Attribute Description Required
family The name of the operating system family to expect. No
name The name of the operating system to expect. No
arch The architecture of the operating system to expect. No
version The version of the operating system to expect. No

Supported values for the family attribute are:

equals

Tests whether the two given values are equal.

Attribute Description Required
arg1 First value to test. Yes
arg2 Second value to test. Yes
casesensitive Perform a case sensitive comparison. Default is true. No
trim Trim whitespace from arguments before comparing them. Default is false. No
forcestring Force string comparison of arg1/arg2. Default is false. Since Apache Ant 1.8.1 No

isset

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

Attribute Description Required
property The name of the property to test. Yes

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.

Attribute Description Required
url The full URL of the page to request. The web server must return a status code below the value of errorsBeginAt Yes.
errorsBeginAt The lowest HTTP response code that signals an error; by default '400'; server errors, not-authorized, not-found and the like are detected No
requestMethod The HTTP method to be used when issuing the request. Any of GET, POST, HEAD, OPTIONS, PUT, DELETEm and TRACE are valid, subject to protocol restrictions. The default if not specified is "GET".
since Ant 1.8.0		 No
followRedirects Whether redirects should be followed. The default is true
since Ant 1.9.7		 No

socket

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

Attribute Description Required
server The DNS name or IP address of the server. Yes.
port The port number to connect to. Yes.

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. NB: 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.

Attribute Description Required
file1 First file to test Yes
file2 Second file to test Yes
textfile Whether to ignore line endings when comparing files; defaults to false which triggers a binary comparison. Since Ant 1.7 No

contains

Tests whether a string contains another one.

Attribute Description Required
string The string to search in. Yes
substring The string to search for. Yes
casesensitive Perform a case sensitive comparison. Default is true. No

istrue

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

Attribute Description Required
value value to test Yes 
<istrue value="${someproperty}"/>
<istrue value="false"/>

isfalse

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

Attribute Description Required
value value to test Yes 
<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.

This condition has been added in Apache Ant 1.6.

Attribute Description Required
refid The id of the reference to test. Yes
type Name of the data type or task this reference is expected to be. No

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.

This condition was added in Apache Ant 1.7.

Attribute Description Required
file The jarfile that is to be tested for the presence of a signature. Yes
name The signature name to check for. No

isfileselected

Test whether a file passes an embedded selector.

This condition was added in Apache Ant 1.6.3.

Attribute Description Required
file The file to check if is passes the embedded selector. Yes
basedir The base directory to use for name based selectors. It this is not set, the project's basedirectory will be used. No

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.

This condition was added in Apache Ant 1.7.

Attribute Description Required
name name of the type Yes
uri The uri that this type lives in. No

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.

This condition was added in Apache Ant 1.7.

Attribute Description Required
language script language Yes
manager The script engine manager to use. See the script task for using this attribute. No - default is "auto"
value default boolean value No -default is "false"
src filename of script source No
setbeans whether to have all properties, references and targets as global variables in the script. since Ant 1.8.0 No, default is "true".
classpath The classpath to pass into the script. No
classpathref The classpath to use, given as a reference to a path defined elsewhere. No
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/

This condition was added in Apache Ant 1.7.

Attribute Description Required
property property to set one of property or feature
feature feature to set one of property or feature
value string (property) or boolean (feature) For property tests, but not for feature tests 
<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 Java1.5+ 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.

This condition was added in Apache Ant 1.7.

Attribute Description Required
host host to check for one of url or host
url URL containing hostname one of url or host
timeout timeout in seconds no, default is 30s 
<condition property="offline">
  <isreachable url="http://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

This condition is a facet of the Length task. It is used to test the length of a string or one or more files. Since Ant 1.6.3 

<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

Test the return code of an executable (see the Exec task) for failure. Since Ant 1.7

Attribute Description Required
code The return code to test. Yes

resourcecount

This condition is a facet of the ResourceCount task. It is used to test the size of a resource collection. Since Ant 1.7 

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

Verify that a resource collection is not empty.

resourcesmatch

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. NB: 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. Since Ant 1.7

Attribute Description Required
astext Whether to ignore line endings when comparing resource content; defaults to false, while true triggers a binary comparison. No

resourcecontains

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. Since Ant 1.7.1

Attribute Description Required
resource Name of a file that is the resource to test. One of the two
refid Reference to a resource defined inside the project.
substring The string to search for. Yes
casesensitive Perform a case sensitive comparison. Default is true. No

hasmethod

Tests for a class having a method or field. If the class is not found or fails to load, the build fails. Since Ant 1.7

Attribute Description Required
classname name of the class to load yes
field name of a field to look for one of field or method
method name of a method to look for one of field or method
ignoreSystemClasses should system classes be ignored? No -default is false
classpath a class path No
classpathref reference to a class path No

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 ArrayList class.

matches

Test if the specified string matches the specified regular expression pattern. Since Ant 1.7

Attribute Description Required
string The string to test. Yes
pattern The regular expression pattern used to test. Yes, unless there is a nested <regexp> element.
casesensitive Perform a case sensitive match. Default is true. No
multiline Perform a multi line match. Default is false. No
singleline This allows '.' to match new lines. SingleLine is not to be confused with multiline, SingleLine is a perl regex term, it corresponds to dotall in java regex. Default is false. No

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

Tests a partition to see if there is enough space. Since Ant 1.7.0

Needed attribute can be specified using standard computing terms:

Attribute Description Required
partition The partition or filesystem to check for freespace Yes
needed The amount of freespace needed. Yes

An example: 

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

islastmodified

Tests the last modified date of a resource. Since Ant 1.8.0

Attribute Description Required
millis Specifies the expected modification time of the resource in milliseconds since midnight Jan 1 1970. Exactly one of the two.
datetime Specifies the expected modification time of the resource. The special value "now" indicates the current time.
pattern SimpleDateFormat-compatible pattern string. Defaults to MM/DD/YYYY HH:MM AM_or_PM or MM/DD/YYYY HH:MM:SS AM_or_PM. No
mode How to compare the timestamp. Accepted values are "equals", "before", "not-before", "after" and "not-after". No, defaults to "equals".

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

Tests a resource for existence. since Ant 1.8.0

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

An example: 

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

javaversion

Tests the version of the JVM executing Ant. Since Ant 1.9.10

Attribute Description Required
atleast The version that this JVM is at least. The format is major.minor.point. Starting with Java9 really only the major number is determined. No One of these.
exactly The version that this JVM is exactly. The format is major.minor.point. Starting with Java9 really only the major number is determined. No

An example: 

<javaversion atleast="9"/>

will evaluate to true if the current JVM is Java9 or above.