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- <html lang="en">
-
- <head>
- <link rel="stylesheet" type="text/css" href="stylesheets/style.css">
- <title>Writing a Simple Buildfile</title>
- </head>
-
- <body>
- <h1>Using Apache Ant</h1>
- <h2 id="buildfile">Writing a Simple Buildfile</h2>
- <p>Apache Ant's buildfiles are written in XML. Each buildfile contains one project and at least one (default)
- target. Targets contain task elements. Each task element of the buildfile can have an <var>id</var> attribute and can
- later be referred to by the value supplied to this. The value has to be unique. (For additional information, see
- the <a href="#tasks">Tasks</a> section below.)</p>
-
- <h3 id="projects">Projects</h3>
- <p>A <em>project</em> has three attributes:</p>
- <table class="attr">
- <tr>
- <th scope="col">Attribute</th>
- <th scope="col">Description</th>
- <th scope="col">Required</th>
- </tr>
- <tr>
- <td>name</td>
- <td>the name of the project.</td>
- <td>No</td>
- </tr>
- <tr>
- <td>default</td>
- <td>the default target to use when no target is supplied.</td>
- <td>No; however, <em>since Ant 1.6.0</em>, every project includes an implicit target that contains any and all
- top-level tasks and/or types. This target will always be executed as part of the project's initialization, even
- when Ant is run with the <a href="running.html#options"><kbd>-projecthelp</kbd></a> option.
- </td>
- </tr>
- <tr>
- <td>basedir</td>
- <td>the base directory from which all path calculations are done. A relative path is resolved relative to the
- directory containing the buildfile.
- </td>
- <td>No; defaults to the parent directory of the buildfile, unless overridden by the project's <var>basedir</var> or
- the <code>basedir</code> property</td>
- </tr>
- </table>
- <p>Optionally, a description for the project can be provided as a top-level <code><description></code> element
- (see the <a href="Types/description.html">description</a> type).</p>
-
- <p>Each project defines one or more <em>targets</em>. A target is a set of <em>tasks</em> you want to be executed. When
- starting Ant, you can select which target(s) you want to have executed. When no target is given, the
- project's <var>default</var> is used.</p>
-
- <h3 id="targets">Targets</h3>
- <p>A target can depend on other targets. You might have a target for compiling, for example, and a target for creating a
- distributable. You can only build a distributable when you have compiled first, so the <q>distribute</q>
- target <em>depends on</em> the <q>compile</q> target. Ant resolves these dependencies.</p>
- <p>It should be noted, however, that Ant's <var>depends</var> attribute only specifies the <em>order</em> in which
- targets should be executed—it does not affect whether the target that specifies the dependency(s) gets executed if
- the dependent target(s) did not (need to) run.</p>
-
- <p>More information can be found in the dedicated <a href="targets.html">manual page</a>.</p>
-
- <h3 id="tasks">Tasks</h3>
- <p>A task is a piece of code that can be executed.</p>
- <p>A task can have multiple attributes (or arguments, if you prefer). The value of an attribute might contain references
- to a property. These references will be resolved before the task is executed.</p>
- <p>Tasks have a common structure:</p>
-
- <pre><<i>name</i> <var>attribute1</var>="<i>value1</i>" <var>attribute2</var>="<i>value2</i>" ... /></pre>
-
- <p>where <code><i>name</i></code> is the name of the task, <var>attributeN</var> is the attribute name,
- and <code><i>valueN</i></code> is the value for this attribute.</p>
- <p>There is a set of <a href="tasklist.html" target="navFrame">built-in tasks</a>, but it is also very easy
- to <a href="develop.html#writingowntask">write your own</a>.</p>
- <p>All tasks can have a <var>name</var> attribute. The value of this attribute will be used in the logging messages
- generated by Ant.</p>
- <p>Tasks can be assigned an <var>id</var> attribute:</p>
-
- <pre><<i>taskname</i> <var>id</var>="<i>taskID</i>" ... /></pre>
-
- <p>where <code><i>taskname</i></code> is the name of the task, and <code><i>taskID</i></code> is a unique identifier for
- this task. You can refer to the corresponding task object in scripts or other tasks via this name. For example, in
- scripts you could do:</p>
-
- <pre>
- <script ... >
- task1.setFoo("bar");
- </script></pre>
- <p>to set the <code>foo</code> attribute of this particular task instance. In another task (written in Java), you can
- access the instance via <code class="code">project.getReference("task1")</code>.</p>
- <p>Note 1: If <q>task1</q> has not been run yet, then it has not been configured (ie., no attributes have been set), and
- if it is going to be configured later, anything you've done to the instance may be overwritten.</p>
- <p>Note 2: Future versions of Ant will most likely <em>not</em> be backward-compatible with this behaviour, since there
- will likely be no task instances at all, only proxies.</p>
-
- <h3 id="properties">Properties</h3>
-
- <p>Properties are an important way to customize a build process or
- to just provide shortcuts for strings that are used repeatedly
- inside a buildfile.</p>
-
- <p>In its most simple form properties are defined in the buildfile
- (for example by the <a href="Tasks/property.html">property</a>
- task) or might be set outside Ant. A property has a name and a
- value; the name is case-sensitive. Properties may be used in the
- value of task attributes or in the nested text of tasks that support
- them. This is done by placing the property name between
- <q>${</q> and <q>}</q> in the
- attribute value. For example, if there is a <code>builddir</code>
- property with the value <q>build</q>, then this could be used
- in an attribute like this: <samp>${builddir}/classes</samp>. This
- is resolved at run-time as <samp>build/classes</samp>.</p>
-
- <p><em>Since Ant 1.8.0</em>, property expansion has become much more powerful
- than simple key value pairs, more details can be
- found <a href="properties.html">in the concepts section</a> of this
- manual.</p>
-
- <h3 id="example">Example Buildfile</h3>
- <pre>
- <project name="MyProject" default="dist" basedir=".">
- <description>
- simple example build file
- </description>
- <!-- set global properties for this build -->
- <property name="src" location="src"/>
- <property name="build" location="build"/>
- <property name="dist" location="dist"/>
-
- <target name="init">
- <!-- Create the time stamp -->
- <tstamp/>
- <!-- Create the build directory structure used by compile -->
- <mkdir dir="${build}"/>
- </target>
-
- <target name="compile" depends="init"
- description="compile the source">
- <!-- Compile the Java code from ${src} into ${build} -->
- <javac srcdir="${src}" destdir="${build}"/>
- </target>
-
- <target name="dist" depends="compile"
- description="generate the distribution">
- <!-- Create the distribution directory -->
- <mkdir dir="${dist}/lib"/>
-
- <!-- Put everything in ${build} into the MyProject-${DSTAMP}.jar file -->
- <jar jarfile="${dist}/lib/MyProject-${DSTAMP}.jar" basedir="${build}"/>
- </target>
-
- <target name="clean"
- description="clean up">
- <!-- Delete the ${build} and ${dist} directory trees -->
- <delete dir="${build}"/>
- <delete dir="${dist}"/>
- </target>
- </project></pre>
-
- <p>Notice that we are declaring properties outside any target. <em>Since Ant 1.6</em>, all tasks can be declared outside
- targets (earlier version only allowed <code><property></code>, <code><typedef></code>
- and <code><taskdef></code>). When you do this they are evaluated before any targets are executed. Some tasks
- will generate build failures if they are used outside of targets as they may cause infinite loops otherwise
- (<code><antcall></code> for example).</p>
-
- <p>We have given some targets descriptions; this causes the <kbd>-projecthelp</kbd> invocation option to list them as
- public targets with the descriptions; the other target is internal and not listed.</p>
- <p>Finally, for this target to work the source in the <samp>src</samp> subdirectory should be stored in a directory tree
- which matches the package names. Check the <code><javac></code> task for details.</p>
-
- <h3 id="filters">Token Filters</h3>
- <p>A project can have a set of tokens that might be automatically expanded if found when a file is copied, when the
- filtering-copy behavior is selected in the tasks that support this. These might be set in the buildfile by
- the <a href="Tasks/filter.html">filter</a> task.</p>
- <p>Since this can potentially be a very harmful behavior, the tokens in the files <strong>must</strong> be of the
- form <code>@<var>token</var>@</code>, where <var>token</var> is the token name that is set in
- the <code><filter></code> task. This token syntax matches the syntax of other build systems that perform such
- filtering and remains sufficiently orthogonal to most programming and scripting languages, as well as with documentation
- systems.</p>
- <p><strong>Note</strong>: If a token with the format <code>@<var>token</var>@</code> is found in a file, but no filter
- is associated with that token, no changes take place; therefore, no escaping method is available—but as long as
- you choose appropriate names for your tokens, this should not cause problems.</p>
- <p><strong>Warning</strong>: If you copy binary files with filtering turned on, you can corrupt the files. This feature
- should be used with text files <em>only</em>.</p>
-
- <h3 id="path">Path-like Structures</h3>
- <p>You can specify <code>PATH</code>- and <code>CLASSPATH</code>-type references using both <q>:</q> and <q>;</q> as
- separator characters. Ant will convert the separator to the correct character of the current operating system.</p>
- <p>Wherever path-like values need to be specified, a nested element can be used. This takes the general form of:</p>
- <pre>
- <classpath>
- <pathelement path="${classpath}"/>
- <pathelement location="lib/helper.jar"/>
- </classpath></pre>
- <p>The <var>location</var> attribute specifies a single file or directory relative to the project's base directory (or
- an absolute filename), while the <var>path</var> attribute accepts colon- or semicolon-separated lists of
- locations. The <var>path</var> attribute is intended to be used with predefined paths—in any other case, multiple
- elements with <var>location</var> attributes should be preferred.</p>
- <p><em>Since Ant 1.8.2</em> the <var>location</var> attribute can also contain a wildcard in its last path component
- (i.e. it can end in a <q>*</q>) in order to support wildcard <code>CLASSPATH</code>s introduced with Java 6. Ant will
- not expand or evaluate the wildcards and the resulting path may not work as anything else but
- a <code>CLASSPATH</code>—or even as a <code>CLASSPATH</code> for JVM prior to Java 6.</p>
- <p>As a shortcut, the <code><classpath></code> tag
- supports <var>path</var> and
- <var>location</var> attributes of its own, so:</p>
- <pre>
- <classpath>
- <pathelement path="${classpath}"/>
- </classpath>
- </pre>
- <p>can be abbreviated to:</p>
- <pre><classpath path="${classpath}"/></pre>
- <p>In addition, one or more <a href="Types/resources.html#collection">resource collections</a> can be specified as
- nested elements (these must consist of <a href="Types/resources.html#file">file</a>-type resources only). Additionally,
- it should be noted that although resource collections are processed in the order encountered, certain resource
- collection types such as <a href="Types/fileset.html">fileset</a>, <a href="Types/dirset.html">dirset</a>
- and <a href="Types/resources.html#files">files</a> are undefined in terms of order.</p>
- <pre>
- <classpath>
- <pathelement path="${classpath}"/>
- <fileset dir="lib">
- <include name="**/*.jar"/>
- </fileset>
- <pathelement location="classes"/>
- <dirset dir="${build.dir}">
- <include name="apps/**/classes"/>
- <exclude name="apps/**/*Test*"/>
- </dirset>
- <filelist refid="third-party_jars"/>
- </classpath></pre>
- <p>This builds a path that holds the value of <samp>${classpath}</samp>, followed by all jar files in
- the <samp>lib</samp> directory, the <samp>classes</samp> directory, all directories named <samp>classes</samp> under
- the <samp>apps</samp> subdirectory of <samp>${build.dir}</samp>, except those that have the text <code>Test</code> in
- their name, and the files specified in the referenced FileList.</p>
- <p>If you want to use the same path-like structure for several tasks, you can define them with
- a <code><path></code> element at the same level as <code><target></code>s, and reference them via their
- <var>id</var> attribute—see <a href="#references">References</a> for an
- example.</p>
-
- <p>By default a path-like structure will re-evaluate all nested resource collections whenever it is used, which may lead
- to unnecessary re-scanning of the filesystem. <em>Since Ant 1.8.0</em>, path has an optional <var>cache</var>
- attribute, if it is set to <q>true</q>, the path instance will only scan its nested resource collections once and assume
- it doesn't change during the build anymore (the default for <var>cache</var> still is <q>false</q>). Even if you are
- using the path only in a single task it may improve overall performance to set <var>cache</var> to <q>true</q> if you
- are using complex nested constructs.</p>
-
- <p>A path-like structure can include a reference to another path-like structure (a path being itself a resource
- collection) via nested <code><path></code> elements:</p>
- <pre>
- <path id="base.path">
- <pathelement path="${classpath}"/>
- <fileset dir="lib">
- <include name="**/*.jar"/>
- </fileset>
- <pathelement location="classes"/>
- </path>
-
- <path id="tests.path" cache="true">
- <path refid="base.path"/>
- <pathelement location="testclasses"/>
- </path></pre>
- <p>The shortcuts previously mentioned for <code><classpath></code> are also valid
- for <code><path></code>. For example:</p>
- <pre>
- <path id="base.path">
- <pathelement path="${classpath}"/>
- </path></pre>
- <p>can be written as:</p>
- <pre><path id="base.path" path="${classpath}"/></pre>
- <h4 id="pathshortcut">Path Shortcut</h4>
- <p><em>Since Ant 1.6</em>, there is a shortcut for converting paths to OS specific strings in properties. One can use
- the expression <samp>${toString:<em>pathreference</em>}</samp> to convert a path element reference to a string that can
- be used for a path argument. For example:</p>
- <pre>
- <path id="lib.path.ref">
- <fileset dir="lib" includes="*.jar"/>
- </path>
- <javac srcdir="src" destdir="classes">
- <compilerarg arg="-Xbootclasspath/p:${toString:lib.path.ref}"/>
- </javac></pre>
-
- <h3 id="arg">Command-line Arguments</h3>
- <p>Several tasks take arguments that will be passed to another process on the command line. To make it easier to specify
- arguments that contain space characters, nested <code>arg</code> elements can be used.</p>
- <table class="attr">
- <tr>
- <th scope="col">Attribute</th>
- <th scope="col">Description</th>
- <th scope="col">Required</th>
- </tr>
- <tr>
- <td>value</td>
- <td>a single command-line argument; can contain space characters.</td>
- <td rowspan="5">Exactly one of these.</td>
- </tr>
- <tr>
- <td>file</td>
- <td class="left">The name of a file as a single command-line argument; will be replaced with the absolute filename
- of the file.</td>
- </tr>
- <tr>
- <td>path</td>
- <td class="left">A string that will be treated as a path-like string as a single command-line argument; you can
- use <q>;</q> or <q>:</q> as path separators and Ant will convert it to the platform's local conventions.</td>
- </tr>
- <tr>
- <td>pathref</td>
- <td class="left"><a href="#references">Reference</a> to a path defined elsewhere. Ant will convert it to the
- platform's local conventions.</td>
- </tr>
- <tr>
- <td>line</td>
- <td class="left">a space-delimited list of command-line arguments.</td>
- </tr>
- <tr>
- <td>prefix</td>
- <td>A fixed string to be placed in front of the argument. In the case of a line broken into parts, it will be placed
- in front of every part. <em>Since Ant 1.8.</em></td>
- <td>No</td>
- </tr>
- <tr>
- <td>suffix</td>
- <td>A fixed string to be placed immediately after the argument. In the case of a line broken into parts, it will be
- placed after every part. <em>Since Ant 1.8.</em></td>
- <td>No</td>
- </tr>
- </table>
-
- <p>It is highly recommended to avoid the <var>line</var> version when possible. Ant will try to split the command line
- in a way similar to what a (Unix) shell would do, but may create something that is very different from what you expect
- under some circumstances.</p>
-
- <h4>Examples</h4>
- <pre><arg value="-l -a"/></pre>
- <p>is a single command-line argument containing a space character, <em>not</em> separate options <q>-l</q>
- and <q>-a</q>.</p>
- <pre><arg line="-l -a"/></pre>
- <p>This is a command line with two separate options, <q>-l</q> and <q>-a</q>.</p>
- <pre><arg path="/dir;/dir2:\dir3"/></pre>
- <p>is a single command-line argument with the value <code>\dir;\dir2;\dir3</code> on DOS-based systems
- and <code>/dir:/dir2:/dir3</code> on Unix(-like) systems.</p>
-
- <h3 id="references">References</h3>
-
- <p>Any project element can be assigned an identifier using its <var>id</var> attribute. In most cases the element can
- subsequently be referenced by specifying the <var>refid</var> attribute on an element of the same type. This can be
- useful if you are going to replicate the same snippet of XML over and over again—using
- a <code><classpath></code> structure more than once, for example.</p>
- <p>The following example:</p>
- <pre>
- <project ... >
- <target ... >
- <rmic ...>
- <classpath>
- <pathelement location="lib/"/>
- <pathelement path="${java.class.path}/"/>
- <pathelement path="${additional.path}"/>
- </classpath>
- </rmic>
- </target>
-
- <target ... >
- <javac ...>
- <classpath>
- <pathelement location="lib/"/>
- <pathelement path="${java.class.path}/"/>
- <pathelement path="${additional.path}"/>
- </classpath>
- </javac>
- </target>
- </project></pre>
- <p>could be rewritten as:</p>
- <pre>
- <project ... >
- <path id="project.class.path">
- <pathelement location="lib/"/>
- <pathelement path="${java.class.path}/"/>
- <pathelement path="${additional.path}"/>
- </path>
-
- <target ... >
- <rmic ...>
- <classpath refid="project.class.path"/>
- </rmic>
- </target>
-
- <target ... >
- <javac ...>
- <classpath refid="project.class.path"/>
- </javac>
- </target>
- </project></pre>
- <p>All tasks that use nested elements
- for <a href="Types/patternset.html">PatternSet</a>s, <a href="Types/fileset.html">FileSet</a>s, <a href="Types/zipfileset.html">ZipFileSet</a>s
- or <a href="#path">path-like structures</a> accept references to these structures as shown in the
- examples. Using <var>refid</var> on a task will ordinarily have the same effect (referencing a task already declared),
- but the user should be aware that the interpretation of this attribute is dependent on the implementation of the element
- upon which it is specified. Some tasks (the <a href="Tasks/property.html">property</a> task is a handy example)
- deliberately assign a different meaning to <var>refid</var>.</p>
-
- <h3 id="external-tasks">Use of external tasks</h3>
- <p>Ant supports a plugin mechanism for using third party tasks. For using them you have to do two steps:</p>
- <ol>
- <li>place their implementation somewhere where Ant can find them.</li>
- <li>declare them.</li>
- </ol>
- <p>Don't add anything to the <code>CLASSPATH</code> environment variable—this is often the reason for very obscure
- errors. Use Ant's own <a href="install.html#optionalTasks">mechanisms</a> for adding libraries:</p>
- <ul>
- <li>via command line argument <kbd>-lib</kbd></li>
- <li>adding to <code>${user.home}/.ant/lib</code></li>
- <li>adding to <code>${ant.home}/lib</code></li>
- </ul>
- <p>For the declaration there are several ways:</p>
- <ul>
- <li>declare a single task per using instruction using
- <code><<a href="Tasks/taskdef.html">taskdef</a> name="taskname"
- classname="ImplementationClass"/></code><br/>
- <code class="code"><taskdef name="for" classname="net.sf.antcontrib.logic.For"/> <for
- ... /></code>
- </li>
- <li>declare a bundle of tasks using a <samp>properties</samp> file holding these taskname–ImplementationClass
- pairs and <code><taskdef></code><br/>
- <code class="code"><taskdef resource="net/sf/antcontrib/antcontrib.properties"/> <for
- ... /></code>
- </li>
- <li>declare a bundle of tasks using an <a href="Types/antlib.html">xml file</a> holding these
- taskname-ImplementationClass-pairs and <code><taskdef></code><br/>
- <code class="code"><taskdef resource="net/sf/antcontrib/antlib.xml"/> <for ... /></code>
- </li>
- <li>declare a bundle of tasks using an xml file named <samp>antlib.xml</samp>, XML namespace
- and <a href="Types/antlib.html#antlibnamespace"><code>antlib:</code> protocol handler</a><br/>
- <code class="code"><project xmlns:ac="antlib:net.sf.antcontrib"/> <ac:for ... /></code>
- </li>
- </ul>
-
- If you need a special function, you should
- <ol>
- <li>have a look at this manual, because Ant provides lot of tasks</li>
- <li>have a look at the external task page <a href="https://ant.apache.org/external.html" target="_top">online</a></li>
- <li>have a look at the external task <a href="https://wiki.apache.org/ant/AntExternalTaskdefs" target="_top">wiki
- page</a></li>
- <li>ask on the <a href="https://ant.apache.org/mail.html#User%20List" target="_top">Ant user</a> list</li>
- <li><a href="tutorial-writing-tasks.html">implement</a> (and share) your own</li>
- </ol>
-
- </body>
- </html>
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