youys
/
ant

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<html>
<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 class="code">
&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 class="code">
&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="_blank">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 class="code">
public class HelloWorld {
    public void execute() {
        System.out.println("Hello World");
    }
}</pre>
<p>and we can compile and jar it with <code>ant</code> (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="_blank"><code>&lt;taskdef&gt;</code>
[2]</a>.  And for easier process we change the <var>default</var> attribute:</p>
<pre class="code">
&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 <code>ant</code> 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>public void execute()</code>. This
class is wrapped by Ant's <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>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 class="code">
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 <code>ant</code> 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>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 class="code">
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>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>execute()</code> is called, the Project object is available.</p>
<p>Here are two useful methods from class Project:</p>
<ul>
  <li><code>String getProperty(String propertyName)</code></li>
  <li><code>String replaceProperties(String value)</code></li>
</ul>

<p>The method <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>public void
set<code>&lt;attributename&gt;</code>(<code>&lt;type&gt;</code> newValue)</code> method and Ant will do the rest via
reflection.</p>
<pre class="code">
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>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>log()</code> method can't handle a <code>null</code> value as
parameter and throws a NullPointerException.  (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 class="code">
    &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>int</code>, <code>long</code>, ...</li>
<li>their wrapper classes like <code>java.lang.Integer</code>, <code>java.lang.Long</code>, ...</li>
<li><code>java.lang.String</code></li>
<li>some other classes (e.g. <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>public void addText(String text)</code> method.</p>
<pre class="code">
...
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>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>addText()</code> can be written as:</p>
<pre class="code">
    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>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>execute()</code> method iterates over the list and evaluates its values.</li>
</ol>
<pre class="code">
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>public <i>classname</i> create<i>XML-name</i>()</code>. Therefore we
write in the buildfile</p>
<pre class="code">
        &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 class="code">
&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 class="code">
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 <em>false</em>. 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>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 prepending <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 class="code">
<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>BuildFileRule</code> field
annotated with JUnit's <code>@Rule</code> annotation. As per conventional JUnit4 tests, this class should have no
constructors, or a default no-args constructor, setup methods should be annotated with <code>@Before</code>, tear down
methods annotated with <code>@After</code> and any test method annotated with <code>@Test</code>.
<pre class="code">
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 <code>ant</code> 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 <code>-verbose</code>.  For more information, try flag <code>-debug</code>.</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>main()</code> function: <code>com.apache.tools.ant.launch.Launcher.main()</code></li>
  <li>Task entry point: <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>execute()</code>
of your custom task.  Then set breakpoints in other methods.  This will ensure the class byte-code 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">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">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>