ant/manual/tutorial-writing-tasks.html

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<head>
<title>Tutorial: Writing Tasks</title>
<link rel="stylesheet" type="text/css" href="stylesheets/style.css"/>
</head>
<body>
<h1>Tutorial: Writing Tasks</h1>
<p>This document provides a step by step tutorial for writing
tasks.</p>
<h2>Content</h2>
<ul>
<li><a href="#buildenvironment">Set up the build environment</a></li>
<li><a href="#write1">Write the Task</a></li>
<li><a href="#use1">Use the Task</a></li>
<li><a href="#TaskAdapter">Integration with TaskAdapter</a></li>
<li><a href="#derivingFromTask">Deriving from Apache Ant's Task</a></li>
<li><a href="#accessTaskProject">Accessing the Task's Project</a></li>
<li><a href="#attributes">Attributes</a></li>
<li><a href="#NestedText">Nested Text</a></li>
<li><a href="#NestedElements">Nested Elements</a></li>
<li><a href="#complex">Our task in a little more complex version</a></li>
<li><a href="#TestingTasks">Test the Task</a></li>
<li><a href="#Debugging">Debugging</a></li>
<li><a href="#resources">Resources</a></li>
</ul>
<h2 id="buildenvironment">Set up the build environment</h2>
<p>Apache Ant builds itself, we are using Ant too (why we would write a task if not? :-) therefore we should use Ant for
our build.</p>
<p>We choose a directory as root directory. All things will be done here if I say nothing different. I will reference
this directory as <em>root-directory</em> of our project. In this root-directory we create a text file
names <samp>build.xml</samp>. What should Ant do for us?</p>
<ul>
<li>compiles my stuff</li>
<li>make the jar, so that I can deploy it</li>
<li>clean up everything</li>
</ul>
So the buildfile contains three targets.
<pre>
&lt;?xml version="1.0" encoding="UTF-8"?&gt;
&lt;project name="MyTask" basedir="." default="jar"&gt;
&lt;target name="clean" description="Delete all generated files"&gt;
&lt;delete dir="classes"/&gt;
&lt;delete file="MyTasks.jar"/&gt;
&lt;/target&gt;
&lt;target name="compile" description="Compiles the Task"&gt;
&lt;javac srcdir="src" destdir="classes"/&gt;
&lt;/target&gt;
&lt;target name="jar" description="JARs the Task"&gt;
&lt;jar destfile="MyTask.jar" basedir="classes"/&gt;
&lt;/target&gt;
&lt;/project&gt;</pre>
This buildfile uses often the same value (<samp>src</samp>, <samp>classes</samp>, <samp>MyTask.jar</samp>), so we should
rewrite that using <code>&lt;property&gt;</code>s. On second there are some handicaps: <code>&lt;javac&gt;</code>
requires that the destination directory exists; a call of <q>clean</q> with a non existing classes directory will
fail; <q>jar</q> requires the execution of some steps before. So the refactored code is:
<pre>
&lt;?xml version="1.0" encoding="UTF-8"?&gt;
&lt;project name="MyTask" basedir="." default="jar"&gt;
<b>&lt;property name="src.dir" value="src"/&gt;</b>
<b>&lt;property name="classes.dir" value="classes"/&gt;</b>
&lt;target name="clean" description="Delete all generated files"&gt;
&lt;delete dir="<b>${classes.dir}</b>" <b>failonerror="false"</b>/&gt;
&lt;delete file="<b>${ant.project.name}.jar</b>"/&gt;
&lt;/target&gt;
&lt;target name="compile" description="Compiles the Task"&gt;
<b>&lt;mkdir dir="${classes.dir}"/&gt;</b>
&lt;javac srcdir="<b>${src.dir}</b>" destdir="${classes.dir}"/&gt;
&lt;/target&gt;
&lt;target name="jar" description="JARs the Task" <b>depends="compile"</b>&gt;
&lt;jar destfile="${ant.project.name}.jar" basedir="${classes.dir}"/&gt;
&lt;/target&gt;
&lt;/project&gt;</pre>
<p><code>ant.project.name</code> is one of the <a href="properties.html#built-in-props" target="_top">build-in
properties [1]</a> of Ant.</p>
<h2 id="write1">Write the Task</h2>
<p>Now we write the simplest Task&mdash;a HelloWorld Task (what else?). Create a text file <samp>HelloWorld.java</samp>
in the src-directory with:</p>
<pre>
public class HelloWorld {
public void execute() {
System.out.println("Hello World");
}
}</pre>
<p>and we can compile and jar it with <kbd>ant</kbd> (default target is <q>jar</q> and via its <var>depends</var>
attribute the <q>compile</q> is executed before).</p>
<h2 id="use1">Use the Task</h2>
<p>But after creating the jar we want to use our new Task. Therefore we need a new target <q>use</q>. Before we can use
our new task we have to declare it with <a href="Tasks/taskdef.html" target="_top"><code>&lt;taskdef&gt;</code>
[2]</a>. And for easier process we change the <var>default</var> attribute:</p>
<pre>
&lt;?xml version="1.0" encoding="UTF-8"?&gt;
&lt;project name="MyTask" basedir="." default="<b>use</b>"&gt;
...
<b>&lt;target name="use" description="Use the Task" depends="jar"&gt;
&lt;taskdef name="helloworld" classname="HelloWorld" classpath="${ant.project.name}.jar"/&gt;
&lt;helloworld/&gt;
&lt;/target&gt;</b>
&lt;/project&gt;</pre>
<p>Important is the <var>classpath</var> attribute. Ant searches in its <samp>/lib</samp> directory for tasks and our
task isn't there. So we have to provide the right location.</p>
<p>Now we can type in <kbd>ant</kbd> and all should work ...</p>
<pre class="output">
Buildfile: build.xml
compile:
[mkdir] Created dir: C:\tmp\anttests\MyFirstTask\classes
[javac] Compiling 1 source file to C:\tmp\anttests\MyFirstTask\classes
jar:
[jar] Building jar: C:\tmp\anttests\MyFirstTask\MyTask.jar
use:
[helloworld] Hello World
BUILD SUCCESSFUL
Total time: 3 seconds</pre>
<h2 id="TaskAdapter">Integration with TaskAdapter</h2>
<p>Our class has nothing to do with Ant. It extends no superclass and implements no interface. How does Ant know to
integrate? Via name convention: our class provides a method with signature <code class="code">public void
execute()</code>. This class is wrapped by Ant's <code class="code">org.apache.tools.ant.TaskAdapter</code> which is a
task and uses reflection for setting a reference to the project and calling the <code class="code">execute()</code>
method.</p>
<p><em>Setting a reference to the project</em>? Could be interesting. The Project class gives us some nice abilities:
access to Ant's logging facilities getting and setting properties and much more. So we try to use that class:</p>
<pre>
import org.apache.tools.ant.Project;
public class HelloWorld {
private Project project;
public void setProject(Project proj) {
project = proj;
}
public void execute() {
String message = project.getProperty("ant.project.name");
project.log("Here is project '" + message + "'.", Project.MSG_INFO);
}
}</pre>
<p>and the execution with <kbd>ant</kbd> will show us the expected</p>
<pre class="output">
use:
Here is project 'MyTask'.</pre>
<h2 id="derivingFromTask">Deriving from Ant's Task</h2>
<p>Ok, that works ... But usually you will extend <code class="code">org.apache.tools.ant.Task</code>. That class is
integrated in Ant, gets the project reference, provides documentation fields, provides easier access to the logging
facility and (very useful) gives you the exact location where <em>in the buildfile</em> this task instance is used.</p>
<p>Oki-doki&mdash;let's us use some of these:</p>
<pre>
import org.apache.tools.ant.Task;
public class HelloWorld extends Task {
public void execute() {
// use of the reference to Project-instance
String message = getProject().getProperty("ant.project.name");
// Task's log method
log("Here is project '" + message + "'.");
// where this task is used?
log("I am used in: " + getLocation() );
}
}</pre>
<p>which gives us when running</p>
<pre class="output">
use:
[helloworld] Here is project 'MyTask'.
[helloworld] I am used in: C:\tmp\anttests\MyFirstTask\build.xml:23:</pre>
<h2 id="accessTaskProject">Accessing the Task's Project</h2>
<p>The parent project of your custom task may be accessed through method <code class="code">getProject()</code>.
However, do not call this from the custom task constructor, as the return value will be null. Later, when node
attributes or text are set, or method <code class="code">execute()</code> is called, the Project object is
available.</p>
<p>Here are two useful methods from class Project:</p>
<ul>
<li><code class="code">String getProperty(String propertyName)</code></li>
<li><code class="code">String replaceProperties(String value)</code></li>
</ul>
<p>The method <code class="code">replaceProperties()</code> is discussed further in section <a href="#NestedText">Nested
Text</a>.</p>
<h2 id="attributes">Attributes</h2>
<p>Now we want to specify the text of our message (it seems that we are rewriting the <code>&lt;echo/&gt;</code> task
:-). First we well do that with an attribute. It is very easy&mdash;for each attribute provide
a <code class="code">public void set<i>Attributename</i>(<i>Type</i> newValue)</code> method and Ant will do the rest
via reflection.</p>
<pre>
import org.apache.tools.ant.Task;
import org.apache.tools.ant.BuildException;
public class HelloWorld extends Task {
String message;
public void setMessage(String msg) {
message = msg;
}
public void execute() {
if (message == null) {
throw new BuildException("No message set.");
}
log(message);
}
}</pre>
<p>Oh, what's that in <code class="code">execute()</code>? Throw a <code>BuildException</code>? Yes, that's the usual
way to show Ant that something important is missed and complete build should fail. The string provided there is written
as build-fails-message. Here it's necessary because the <code class="code">log()</code> method can't handle
a <code>null</code> value as parameter and throws a <code>NullPointerException</code>. (Of course you can initialize
the <var>message</var> with a default string.)</p>
<p>After that we have to modify our buildfile:</p>
<pre>
&lt;target name="use" description="Use the Task" depends="jar"&gt;
&lt;taskdef name="helloworld"
classname="HelloWorld"
classpath="${ant.project.name}.jar"/&gt;
&lt;helloworld <b>message="Hello World"</b>/&gt;
&lt;/target&gt;</pre>
<p>That's all.</p>
<p>Some background for working with attributes: Ant supports any of these datatypes as arguments of the set-method:</p>
<ul>
<li>primitive data types like <code class="code">int</code>, <code class="code">long</code>, ...</li>
<li>their wrapper classes like <code class="code">java.lang.Integer</code>, <code class="code">java.lang.Long</code>,
...</li>
<li><code class="code">java.lang.String</code></li>
<li>some other classes (e.g. <code class="code">java.io.File</code>; see <a href="develop.html#set-magic">Manual
'Writing Your Own Task' [3]</a>)</li>
<li>Any Java Object parsed from Ant 1.8's <a href="Tasks/propertyhelper.html">Property
Helper</a></li>
</ul>
<p>Before calling the set-method all properties are resolved. So a <code>&lt;helloworld message="${msg}"/&gt;</code>
would not set the message string to <q>${msg}</q> if there is a property <code>msg</code> with a set value.</p>
<h2 id="NestedText">Nested Text</h2>
<p>Maybe you have used the <code>&lt;echo&gt;</code> task in a way like <code>&lt;echo&gt;Hello
World&lt;/echo&gt;</code>. For that you have to provide a <code class="code">public void addText(String text)</code>
method.</p>
<pre>
...
public class HelloWorld extends Task {
private String message;
...
public void addText(String text) {
message = text;
}
...
}</pre>
<p>But here properties are <strong>not</strong> resolved! For resolving properties we have to use
Project's <code class="code">replaceProperties(String propname)</code> method which takes the property name as argument
and returns its value (or <code>${propname}</code> if not set).</p>
<p>Thus, to replace properties in the nested node text, our method <code class="code">addText()</code> can be written
as:</p>
<pre>
public void addText(String text) {
message = getProject().replaceProperties(text);
}</pre>
<h2 id="NestedElements">Nested Elements</h2>
<p>There are several ways for inserting the ability of handling nested elements. See
the <a href="develop.html#nested-elements">Manual [4]</a> for other. We use the first way of the three described
ways. There are several steps for that:</p>
<ol>
<li>We create a class for collecting all the info the nested element should contain. This class is created by the same
rules for attributes and nested elements as for the task (<code class="code">set<i>Attributename</i>()</code>
methods).</li>
<li>The task holds multiple instances of this class in a list.</li>
<li>A factory method instantiates an object, saves the reference in the list and returns it to Ant Core.</li>
<li>The <code class="code">execute()</code> method iterates over the list and evaluates its values.</li>
</ol>
<pre>
import java.util.ArrayList;
import java.util.List;
...
public void execute() {
if (message != null) log(message);
for (Message msg : messages) { <b>// 4</b>
log(msg.getMsg());
}
}
List&lt;Message&gt; messages = new ArrayList&lt;&gt;(); <b>// 2</b>
public Message createMessage() { <b>// 3</b>
Message msg = new Message();
messages.add(msg);
return msg;
}
public class Message { <b>// 1</b>
public Message() {}
String msg;
public void setMsg(String msg) { this.msg = msg; }
public String getMsg() { return msg; }
}
...</pre>
<p>Then we can use the new nested element. But where is XML-name for that defined? The mapping XML-name &rarr;
classname is defined in the factory method: <code class="code">public <i>classname</i>
create<i>XML-name</i>()</code>. Therefore we write in the buildfile</p>
<pre>
&lt;helloworld&gt;
&lt;message msg="Nested Element 1"/&gt;
&lt;message msg="Nested Element 2"/&gt;
&lt;/helloworld&gt;</pre>
<p>Note that if you choose to use methods 2 or 3, the class that represents the nested element must be declared
as <code>static</code></p>
<h2 id="complex">Our task in a little more complex version</h2>
<p>For recapitulation now a little refactored buildfile:</p>
<pre>
&lt;?xml version="1.0" encoding="UTF-8"?&gt;
&lt;project name="MyTask" basedir="." default="use"&gt;
&lt;property name="src.dir" value="src"/&gt;
&lt;property name="classes.dir" value="classes"/&gt;
&lt;target name="clean" description="Delete all generated files"&gt;
&lt;delete dir="${classes.dir}" failonerror="false"/&gt;
&lt;delete file="${ant.project.name}.jar"/&gt;
&lt;/target&gt;
&lt;target name="compile" description="Compiles the Task"&gt;
&lt;mkdir dir="${classes.dir}"/&gt;
&lt;javac srcdir="${src.dir}" destdir="${classes.dir}"/&gt;
&lt;/target&gt;
&lt;target name="jar" description="JARs the Task" depends="compile"&gt;
&lt;jar destfile="${ant.project.name}.jar" basedir="${classes.dir}"/&gt;
&lt;/target&gt;
&lt;target name="use.init"
description="Taskdef the HelloWorld-Task"
depends="jar"&gt;
&lt;taskdef name="helloworld"
classname="HelloWorld"
classpath="${ant.project.name}.jar"/&gt;
&lt;/target&gt;
&lt;target name="use.without"
description="Use without any"
depends="use.init"&gt;
&lt;helloworld/&gt;
&lt;/target&gt;
&lt;target name="use.message"
description="Use with attribute 'message'"
depends="use.init"&gt;
&lt;helloworld message="attribute-text"/&gt;
&lt;/target&gt;
&lt;target name="use.fail"
description="Use with attribute 'fail'"
depends="use.init"&gt;
&lt;helloworld fail="true"/&gt;
&lt;/target&gt;
&lt;target name="use.nestedText"
description="Use with nested text"
depends="use.init"&gt;
&lt;helloworld&gt;nested-text&lt;/helloworld&gt;
&lt;/target&gt;
&lt;target name="use.nestedElement"
description="Use with nested 'message'"
depends="use.init"&gt;
&lt;helloworld&gt;
&lt;message msg="Nested Element 1"/&gt;
&lt;message msg="Nested Element 2"/&gt;
&lt;/helloworld&gt;
&lt;/target&gt;
&lt;target name="use"
description="Try all (w/out use.fail)"
depends="use.without,use.message,use.nestedText,use.nestedElement"/&gt;
&lt;/project&gt;</pre>
<p>And the code of the task:</p>
<pre>
import org.apache.tools.ant.Task;
import org.apache.tools.ant.BuildException;
import java.util.ArrayList;
import java.util.List;
/**
* The task of the tutorial.
* Print a message or let the build fail.
* @since 2003-08-19
*/
public class HelloWorld extends Task {
/** The message to print. As attribute. */
String message;
public void setMessage(String msg) {
message = msg;
}
/** Should the build fail? Defaults to <i>false</i>. As attribute. */
boolean fail = false;
public void setFail(boolean b) {
fail = b;
}
/** Support for nested text. */
public void addText(String text) {
message = text;
}
/** Do the work. */
public void execute() {
// handle attribute 'fail'
if (fail) throw new BuildException("Fail requested.");
// handle attribute 'message' and nested text
if (message != null) log(message);
// handle nested elements
for (Message msg : messages) {
log(msg.getMsg());
}
}
/** Store nested 'message's. */
List&lt;Message&gt; messages = new ArrayList&lt;&gt;();
/** Factory method for creating nested 'message's. */
public Message createMessage() {
Message msg = new Message();
messages.add(msg);
return msg;
}
/** A nested 'message'. */
public class Message {
// Bean constructor
public Message() {}
/** Message to print. */
String msg;
public void setMsg(String msg) { this.msg = msg; }
public String getMsg() { return msg; }
}
}</pre>
<p>And it works:</p>
<pre class="output">
C:\tmp\anttests\MyFirstTask&gt;ant
Buildfile: build.xml
compile:
[mkdir] Created dir: C:\tmp\anttests\MyFirstTask\classes
[javac] Compiling 1 source file to C:\tmp\anttests\MyFirstTask\classes
jar:
[jar] Building jar: C:\tmp\anttests\MyFirstTask\MyTask.jar
use.init:
use.without:
use.message:
[helloworld] attribute-text
use.nestedText:
[helloworld] nested-text
use.nestedElement:
[helloworld]
[helloworld]
[helloworld]
[helloworld]
[helloworld] Nested Element 1
[helloworld] Nested Element 2
use:
BUILD SUCCESSFUL
Total time: 3 seconds
C:\tmp\anttests\MyFirstTask&gt;ant use.fail
Buildfile: build.xml
compile:
jar:
use.init:
use.fail:
BUILD FAILED
C:\tmp\anttests\MyFirstTask\build.xml:36: Fail requested.
Total time: 1 second
C:\tmp\anttests\MyFirstTask&gt;</pre>
<p>Next step: test ...</p>
<h2 id="TestingTasks">Test the Task</h2>
<p>We have written a test already: the <q>use.*</q> targets in the buildfile. But it's difficult to test that
automatically. Commonly (and in Ant) JUnit is used for that. For testing tasks Ant provides a JUnit
Rule <code class="code">org.apache.tools.ant.BuildFileRule</code>. This class provides some for testing tasks useful
methods: initialize Ant, load a buildfile, execute targets, capture debug and run logs ...</p>
<p>In Ant it is usual that the testcase has the same name as the task with a prepended <code>Test</code>, therefore we
will create a file <samp>HelloWorldTest.java</samp>. Because we have a very small project we can put this file
into <samp>src</samp> directory (Ant's own testclasses are in <samp>/src/testcases/...</samp>). Because we have already
written our tests for "hand-test" we can use that for automatic tests, too. All test supporting classes are a part of
the binary distribution of Ant <em>since Ant 1.7.0</em> in form of <samp>ant-testutil.jar</samp>. You can also build the
jar file from source distro with target "test-jar".
<p>For executing the test and creating a report we need the optional tasks <code>&lt;junit&gt;</code>
and <code>&lt;junitreport&gt;</code>. So we add to the buildfile:</p>
<pre>
<span style="color:gray">&lt;project name="MyTask" basedir="." </span>default="test"<span style="color:gray">&gt;</span>
...
&lt;property name="ant.test.lib" value="ant-testutil.jar"/&gt;
&lt;property name="report.dir" value="report"/&gt;
&lt;property name="junit.out.dir.xml" value="${report.dir}/junit/xml"/&gt;
&lt;property name="junit.out.dir.html" value="${report.dir}/junit/html"/&gt;
&lt;path id="classpath.run"&gt;
&lt;path path="${java.class.path}"/&gt;
&lt;path location="${ant.project.name}.jar"/&gt;
&lt;/path&gt;
&lt;path id="classpath.test"&gt;
&lt;path refid="classpath.run"/&gt;
&lt;path location="${ant.test.lib}"/&gt;
&lt;/path&gt;
&lt;target name="clean" description="Delete all generated files"&gt;
&lt;delete failonerror="false" includeEmptyDirs="true"&gt;
&lt;fileset dir="." includes="${ant.project.name}.jar"/&gt;
&lt;fileset dir="${classes.dir}"/&gt;
&lt;fileset dir="${report.dir}"/&gt;
&lt;/delete&gt;
&lt;/target&gt;
<span style="color:gray">&lt;target name="compile" description="Compiles Vector the Task"&gt;
&lt;mkdir dir="${classes.dir}"/&gt;
&lt;javac srcdir="${src.dir}" destdir="${classes.dir}" </span>classpath="${ant.test.lib}"<span style="color:gray">/&gt;
&lt;/target&gt;</span>
...
&lt;target name="junit" description="Runs the unit tests" depends="jar"&gt;
&lt;delete dir="${junit.out.dir.xml}"/&gt;
&lt;mkdir dir="${junit.out.dir.xml}"/&gt;
&lt;junit printsummary="yes" haltonfailure="no"&gt;
&lt;classpath refid="classpath.test"/&gt;
&lt;formatter type="xml"/&gt;
&lt;batchtest fork="yes" todir="${junit.out.dir.xml}"&gt;
&lt;fileset dir="${src.dir}" includes="**/*Test.java"/&gt;
&lt;/batchtest&gt;
&lt;/junit&gt;
&lt;/target&gt;
&lt;target name="junitreport" description="Create a report for the rest result"&gt;
&lt;mkdir dir="${junit.out.dir.html}"/&gt;
&lt;junitreport todir="${junit.out.dir.html}"&gt;
&lt;fileset dir="${junit.out.dir.xml}"&gt;
&lt;include name="*.xml"/&gt;
&lt;/fileset&gt;
&lt;report format="frames" todir="${junit.out.dir.html}"/&gt;
&lt;/junitreport&gt;
&lt;/target&gt;
&lt;target name="test"
depends="junit,junitreport"
description="Runs unit tests and creates a report"/&gt;
...
<span style="color:gray">&lt;/project&gt;</span></pre>
<p>Back to the <samp>src/HelloWorldTest.java</samp>. We create a class with a
public <code class="code">BuildFileRule</code> field annotated with JUnit's <code class="code">@Rule</code>
annotation. As per conventional JUnit4 tests, this class should have no constructors, nor a default no-args constructor,
setup methods should be annotated with <code class="code">@Before</code>, tear down methods annotated
with <code class="code">@After</code> and any test method annotated with <code class="code">@Test</code>.
<pre>
import org.apache.tools.ant.BuildFileRule;
import org.junit.Assert;
import org.junit.Test;
import org.junit.Before;
import org.junit.Rule;
import org.apache.tools.ant.AntAssert;
import org.apache.tools.ant.BuildException;
public class HelloWorldTest {
@Rule
public final BuildFileRule buildRule = new BuildFileRule();
@Before
public void setUp() {
// initialize Ant
buildRule.configureProject("build.xml");
}
@Test
public void testWithout() {
buildRule.executeTarget("use.without");
assertEquals("Message was logged but should not.", buildRule.getLog(), "");
}
public void testMessage() {
// execute target 'use.nestedText' and expect a message
// 'attribute-text' in the log
buildRule.executeTarget("use.message");
Assert.assertEquals("attribute-text", buildRule.getLog());
}
@Test
public void testFail() {
// execute target 'use.fail' and expect a BuildException
// with text 'Fail requested.'
try {
buildRule.executeTarget("use.fail");
fail("BuildException should have been thrown as task was set to fail");
} catch (BuildException ex) {
Assert.assertEquals("fail requested", ex.getMessage());
}
}
@Test
public void testNestedText() {
buildRule.executeTarget("use.nestedText");
Assert.assertEquals("nested-text", buildRule.getLog());
}
@Test
public void testNestedElement() {
buildRule.executeTarget("use.nestedElement");
AntAssert.assertContains("Nested Element 1", buildRule.getLog());
AntAssert.assertContains("Nested Element 2", buildRule.getLog());
}
}</pre>
<p>When starting <kbd>ant</kbd> we'll get a short message to STDOUT and a nice HTML report.</p>
<pre class="output">
C:\tmp\anttests\MyFirstTask&gt;ant
Buildfile: build.xml
compile:
[mkdir] Created dir: C:\tmp\anttests\MyFirstTask\classes
[javac] Compiling 2 source files to C:\tmp\anttests\MyFirstTask\classes
jar:
[jar] Building jar: C:\tmp\anttests\MyFirstTask\MyTask.jar
junit:
[mkdir] Created dir: C:\tmp\anttests\MyFirstTask\report\junit\xml
[junit] Running HelloWorldTest
[junit] Tests run: 5, Failures: 0, Errors: 0, Time elapsed: 2,334 sec
junitreport:
[mkdir] Created dir: C:\tmp\anttests\MyFirstTask\report\junit\html
[junitreport] Using Xalan version: Xalan Java 2.4.1
[junitreport] Transform time: 661ms
test:
BUILD SUCCESSFUL
Total time: 7 seconds
C:\tmp\anttests\MyFirstTask&gt;</pre>
<h2 id="Debugging">Debugging</h2>
<p>Try running Ant with the flag <kbd>-verbose</kbd>. For more information, try flag <kbd>-debug</kbd>.</p>
<p>For deeper issues, you may need to run the custom task code in a Java debugger. First, get the source for Ant and
build it with debugging information.</p>
<p>Since Ant is a large project, it can be a little tricky to set the right breakpoints. Here are two important
breakpoints for version 1.8:</p>
<ul>
<li>Initial <code class="code">main()</code>
function: <code class="code">com.apache.tools.ant.launch.Launcher.main()</code></li>
<li>Task entry point: <code class="code">com.apache.tools.ant.UnknownElement.execute()</code></li>
</ul>
<p>If you need to debug when a task attribute or the text is set, begin by debugging into
method <code class="code">execute()</code> of your custom task. Then set breakpoints in other methods. This will
ensure the class bytecode has been loaded by JVM.</p>
<h2 id="resources">Resources</h2>
<p>This tutorial and its resources are available via <a href="https://issues.apache.org/bugzilla/show_bug.cgi?id=22570"
target="_top">BugZilla [5]</a>. The ZIP provided there contains</p>
<ul>
<li>this initial version of this tutorial</li>
<li>the buildfile (last version)</li>
<li>the source of the task (last version)</li>
<li>the source of the unit test (last version)</li>
<li>the ant-testutil.jar (nightly build of 2003-08-18)</li>
<li>generated classes</li>
<li>generated jar</li>
<li>generated reports</li>
</ul>
<p>The last sources and the buildfile are also available <a href="tutorial-writing-tasks-src.zip">here [6]</a> inside
the manual.</p>
<p>Used Links:</p>
<ol class="refs">
<li><a href="properties.html#built-in-props">https://ant.apache.org/manual/properties.html#built-in-props</a></li>
<li><a href="Tasks/taskdef.html">https://ant.apache.org/manual/Tasks/taskdef.html</a></li>
<li><a href="develop.html#set-magic">https://ant.apache.org/manual/develop.html#set-magic</a></li>
<li><a href="develop.html#nested-elements">https://ant.apache.org/manual/develop.html#nested-elements</a></li>
<li><a href="https://issues.apache.org/bugzilla/show_bug.cgi?id=22570"
target="_top">https://issues.apache.org/bugzilla/show_bug.cgi?id=22570</a></li>
<li><a href="tutorial-writing-tasks-src.zip">tutorial-writing-tasks-src.zip</a></li>
</ol>
</body>
</html>