Check Properties

In this section, you will learn how to check properties using environment variable whether is set or not.

Check Properties


This example illustrates how to check properties using environment variable whether it is set or not. In this code, there are three properties; the first two are used to define source directory and destination directory. The source directory is 'src' and the destination directory is 'build'. The element <property environment="env"> is a path of jar file dependent on environment variables, and these are available only if you use <property environment="env"> before you import the property file. The following example shows how to check whether TOMCAT_HOME environment variable is set or not. If TOMCAT_HOME environment variable is set, then the output will display build successful... as given below.



<project name="Check Properties" default="compile" basedir=".">

  <property name="dir.src" value="src"/>
  <property name="" value="build"/>
  <property environment="env"/>

  <target name="check">
<fail unless="env.TOMCAT_HOME">TOMCAT_HOME class path must be set</fail>  

  <target name="clean" depends="check">
  <delete dir="${}"/>

  <target name="prepare" depends="clean">
  <mkdir dir="${}"/>

  <target name="compile" depends="prepare" >
  <echo>Compile code...</echo>



But if TOMCAT_HOME environment variable is not set, then the following error message will be displayed.

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