Apache Ant

Apache Ant Hussain Fakhruddin [email_address]

Topics

What , Why, Where?

Installing Ant

build.xml

What is Ant “ Apache Ant is a Java-based build tool. In theory, it is kind of like Make, but without Make's wrinkles” -Apache Ant Website

Why Another such tool?

Q) Why create another tool when make, gnumake, jam, nmake already exist?

They all have some limitations

They are more Shell Based

Limits you to one kind of OS

Why Ant then?

Ant is different

Ant has Java Class like extensions

Use of XML instead of Shell Scripts

Each task is taken care by creating its object

Standardized

Platform Independent

Where to get it

You can get Ant from the following links:

Apache Ant Homepage: http://ant.apache.org/ (Download > Current Release of Ant > apache-ant<version>-bin.zip 11MB Approx)

IDE: Ant comes in as bundled 3 rd party tool/modules with IDEs like Eclipse, Netbeans, Jdeveloper,IntelliJ IDEA

Ant directory structure

Installing Ant

Step 1: Add the bin directory to your path.

Installing Ant

Step 2: Set the ANT_HOME environment variable to the directory where you installed Ant

Installing Ant

Step 3: set the JAVA_HOME environment variable to your JDK

build.xml

Similar to makefile but an XML file

Its the default file where ant will look for what to build, how to build

Has projects, targets, tasks

build.xml ..Cont A build.xml file contains the following: Root Tag : <project> Child Tag: <target> (at least one) Sub Child Tag: <task>

Sample build.xml <project name="example" default="hello"> <target name="hello"> <echo message="My First Ant" /> </target> </project> Project tag(only one ) Task tag Target Tag (at least one)

Output

name: [Optional] Name of the project

basedir: [Optional] The base directory for path calculation.If not set then directory of the build file will be taken as the basedir

default: [Required] The default target to be called when no target is specified in command line. Example: <project name=”hello” default=”first” basedir=”.”>

Three attributes of <project>

A <project> may have one or more <target>

A <target> defines set of <task>

A <target> may depend on other <target>

A <target> gets executed only once

A <target> has properties which determines how it will be executed

A <target> can be specified when executing ant from command line Example: <target name="jar" depends="compile" description="create a Jar file for the application">

<task>

Independent code which can be executed

Can have multiple attributes

Ant has some built-in ready to be used tasks

Example: <jar destfile="hello.jar">

jar is the command, destfile is the parameter

This ant task has the same name as the common java command-line utility, JAR, but is really a call to the ant program's built in jar/zip file support.

Properties

A <project> can have a set of properties

They are kind of Variables.

Project properties can be set using the <property> tag

Example: <property name= “src” location= “src” />

<property name= “build” location= “build” />

<property name= “dist” location= “dist” />

Properties ..Cont

Properties are case sensitive

Can be set in an external file

Task can use/reference this property by “${prop_name}”

Ant supports all system properties. Example: ${os.name} expands to Operating System name

Ant also has built in properties. Example: ${ant.java.version} expands to JVM version ant detected ${ant.file} expands to absolute path of the build.xml

Sample build.xml with properties <project name="MyProject" default="dist" basedir="."> <description> simple example build file </description>  <property name="src" location="src"/> <property name="build" location="build"/> <property name="dist" location="dist"/> <target name="init">  <tstamp/>  <mkdir dir="${build}"/> </target> <target name="compile" depends="init" description="compile the source " >  <javac srcdir="${src}" destdir="${build}"/> </target> <target name="dist" depends="compile" description="generate the distribution" >  <mkdir dir="${dist}/lib"/>  <jar jarfile="${dist}/lib/MyProject-${DSTAMP}.jar" basedir="${build}"/> </target> <target name="clean" description="clean up" >  <delete dir="${build}"/> <delete dir="${dist}"/> </target> </project>

Hello World with Ant Lets compile , pack and run a simple Hello World program in Java. Step 1: Write your Java source code Step 2: Write a build.xml file Step 3: Run Ant with the build.xml

Step 1: Write a simple Hello World in Java public class HelloWorld{ public static void main(String []args) { System.out.println(“Hi, I am from Ant”); } }

Lets write the build.xml

First of all , lets examine what you want to do:

You'd like to Compile

You'd like to package it into a Jar file.

You'd also like to clean up the mess.

Finally you'd like to run your application

Lets create the root tags

<project name= “Hello World” default= “compile”>

..

</project>

build.xml ..cont. Write a project with tasks to compile, package clean and run <project name="Hello World" default="compile"> <target name="compile"> <mkdir dir="dist" /> <javac srcdir="." destdir="dist" /> </target> </project> Make a directory called “dist” Provide source and destination directories

build.xml ..cont <project name="Hello World" default="compile"> <target name="jar"> <mkdir dir="dist/jar"/> <jar destfile="dist/jar/HelloWorld.jar" basedir="dist"> <manifest> <attribute name="Main-Class" value="HelloWorld"/> </manifest> </jar> </target> <target name="compile"> <mkdir dir="dist" /> <javac srcdir="." destdir="dist" /> </target> </project> Package Class Name

build.xml ..cont <project name="Hello World" default="compile"> <target name="run"> <java jar="dist/jar/HelloWorld.jar" fork="true"/> </target> <target name="clean"> <delete dir="dist"/> </target> <target name="jar"> <mkdir dir="dist/jar"/> <jar destfile="dist/jar/HelloWorld.jar" basedir="dist"> <manifest> <attribute name="Main-Class" value="HelloWorld"/> </manifest> </jar> </target> <target name="compile"> <mkdir dir="dist" /> <javac srcdir="." destdir="dist" /> </target> </project> delete the directory created by <mkdir> in the beginning Execute this jar file

Run the Ant Place your files in the classpath and execute: ant compile ant jar ant run or simply, ant compile jar run

Output

Ant Resources Homepage: http://ant.apache.org User Manual: http://jakarta.apache.org/ant/manual/index.html Wiki: http://wiki.apache.org/ant/FrontPage FAQ: http://ant.apache.org/faq.html Books: http://sourceforge.net/projects/antbook Contribution: http://www.apache.org/foundation/contributing.html

Queries?

Thanks for your time About the Author: Hussain Fakhruddin [email_address]