Ant Macros
In Ant, a macro is a reusable block of code that can be parameterized and called from within an Ant build file. Macros can be used to simplify complex build processes and reduce duplication in build files. Here's an example of an Ant macro:
<macrodef name="compile-and-jar">
<attribute name="srcdir"/>
<attribute name="destdir"/>
<attribute name="jarfile"/>
<sequential>
<javac srcdir="@{srcdir}" destdir="@{destdir}"/>
<jar destfile="@{jarfile}" basedir="@{destdir}"/>
</sequential>
</macrodef>
In this example, we've defined a macro named "compile-and-jar" that compiles Java source files and creates a JAR file. The macro takes three attributes: "srcdir" specifies the directory containing the Java source files, "destdir" specifies the output directory for the compiled class files, and "jarfile" specifies the output JAR file. The macro uses the "sequential" task to execute the "javac" and "jar" tasks in sequence.
To use the macro in a build file, we can call it using the @ syntax to pass in values for the macro attributes:
<compile-and-jar srcdir="src" destdir="build/classes" jarfile="dist/MyProject.jar"/>
This will compile the Java source files located in the "src" directory, place the compiled class files in the "build/classes" directory, and create a JAR file named "MyProject.jar" in the "dist" directory.
Macros can also contain nested elements, allowing for even more complex build processes to be encapsulated and reused.
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