Creating targets and their dependencies in ANT build file

A target is a collection of tasks that you want to run as one unit. Targets can have dependencies on other targets. When you create a new Ant buildfile project builder, the default target is set to be run for After a “Clean” and Manual Build and the remaining two kinds; Auto Build and During a “Clean” are set to not be executed. If you want to configure your builder to execute specific targets from your buildfile for specific build kinds then more understanding of what the build kinds are, and more importantly, when they will be executed is required.

We can create target and their dependencies as below in the application build file.

Creating simple Target without dependency

<?xml version="1.0"?>
   <project name="Hello World" default="info" basedir=".">
   
   <target name="info">
      <echo>Hello World - Welcome to Apache Ant Tutorial!!!</echo>
   </target>
   
</project>

 Attributes of target

• name-> The name of the target ant it is mandatory.
• depends-> Comma separated list of all targets that this target depends on and it is optional.
• description->A short description of the target and it is optional.
• if->Allows the execution of a target based on the trueness of a conditional attribute and it is optional.
• unless->Adds the target to the dependency list of the specified Extension Point. An Extension Point is similar to a target, but it does not have any tasks and it is optional.

Creating multiple Targets with dependencies

<?xml version="1.0" encoding="UTF-8"?>
<project name="AlgoTest.makejar" default="makejar" basedir=".">
  <property name="build.dir" value="build" />
  <target name="clean" description="cleans up the build by deleting the build,dist, web directories">
     <delete dir="${build.dir}"/>
   </target>
   <target name="init" depends="clean" description="Setup for build script">   
     <mkdir dir="${build.dir}"/>
   </target>
   <target name="compile" depends="init" description="Compiles .java files to WAR directory">
       <javac srcdir="src" destdir="bin" debug="true"   
            depend="true" includeantruntime="true">
       </javac>
     </target>    
      <target name ="makejar" description="Create a jar for the AlgoTest project" depends="compile">
     <jar jarfile="${build.dir}/AlgoTest.jar" includes="*.class" basedir="bin">
      <manifest>
        <attribute name = "Main-Class" value = "com.dineshonjava.algo.StringPermutation"/>
     </manifest>
     </jar>
   </target>
</project>

As per as we have define targets in the above file have dependencies such as a makejar target may have a dependency on the compile target and compile target may have dependency on the init target and init target may have dependency on the clean target.