Programming Ant

Common Features

1, Initialized Project:

import java.io.File; import org.apache.tools.ant.Project; import org.apache.tools.ant.ProjectHelper; public class InitializedProject extends Project {        public InitializedProject(File buildFile) {               super();               init();                           ProjectHelper projectHelper = ProjectHelper.getProjectHelper();               addReference("ant.projectHelper", projectHelper);               projectHelper.parse(this, buildFile);        } }

2, Share properties with plain java code

    <property file="

userhome/some.properties

" />

3, Organize layered build files or refer tasks/targets/properties in other build file for large scale application

    <import file="

../../../../../build/imports.xml

" />

4, id anywhere for reuse

    <path id="

test.dist.dir.temp

">  

    <pathelement location="

${test.dist.dir}

" />

    <pathelement location="

${dist.dir}

" />

</path>

5, method target anywhere for reuse

    <target name="

dotest

">

        <someoperate />

    </target>

<target name="

TestMemoryLeak

"> <antcall target="

dotest

"> <param name="

propfile

" value="

mem-leak.properties

" /> <param name="

testclass

" value="

MemoryLeakTest

" /> </antcall> </target>

6, synchronized call

    <target name="

xdoclet

" depends="

init, xdoclet.ejb, xdoclet.test

" />

6, script ant

although ant is not a script language, it does glue many operations together, it can combine any "executable programs", such as "Java Class", "OS script", "OS executable program", and ant scripts itself. ant also provides many useful tasks, you can use it instead of batch file.

Special Features for Large Scale Software

1, access environment variable:

<property environment="env"/>
  <echo message="Number of Processors = ${env.NUMBER_OF_PROCESSORS}"/>
  <echo message="ANT_HOME is set to = ${env.ANT_HOME}"/>
      

2, access JVM variable(http://java.sun.com/j2se/1.5.0/docs/api/java/lang/System.html#getProperties()):

Key	Description of Associated Value
java.version	Java Runtime Environment version
java.vendor	Java Runtime Environment vendor
java.vendor.url	Java vendor URL
java.home	Java installation directory
java.vm.specification.version	Java Virtual Machine specification version
java.vm.specification.vendor	Java Virtual Machine specification vendor
java.vm.specification.name	Java Virtual Machine specification name
java.vm.version	Java Virtual Machine implementation version
java.vm.vendor	Java Virtual Machine implementation vendor
java.vm.name	Java Virtual Machine implementation name
java.specification.version	Java Runtime Environment specification version
java.specification.vendor	Java Runtime Environment specification vendor
java.specification.name	Java Runtime Environment specification name
java.class.version	Java class format version number
java.class.path	Java class path
java.library.path	List of paths to search when loading libraries
java.io.tmpdir	Default temp file path
java.compiler	Name of JIT compiler to use
java.ext.dirs	Path of extension directory or directories
os.name	Operating system name
os.arch	Operating system architecture
os.version	Operating system version
file.separator	File separator ("/" on UNIX)
path.separator	Path separator (":" on UNIX)
line.separator	Line separator ("/n" on UNIX)
user.name	User's account name
user.home	User's home directory
user.dir	User's current working directory

3, property is immutable

for large scale software development, all source files include ant build files would be committed to SCM system, but many configuration items are not same in every machine, such as Application Server setup folder and listening port; Combining "environment variable, jvm variable, and immutable property", ant provides a perfect solution for this, you can commit default property files to SCM, and put custom property file in your ${user.home}, as long as your build file would load property files in ${user.home} first. 

(to be continue...)