How to loop macrodef in Ant script?

Currently, I am writing an Ant Script that removes the signatures of signed Jar files.

Removing the signature for a single jar file was successful using the script below.

<project name="unsign">
    <taskdef resource="net/sf/antcontrib/antcontrib.properties" classpath="ant-lib/ant-contrib-0.6.jar" />

    <property name="jarPath" location="C:\Users\Administrator\Desktop\tempDir" />
    <property name="resultPath" location="C:\Users\Administrator\Desktop\tempDir-result" />

    <target name="unsignJar">
        <unsignjar jarFile="${jarPath}/com.google.guava_15.0.0.v201403281430.jar" />
    </target>

    <macrodef name="unsignjar" description="Unsign a jar file">
        <attribute name="jarfile" description="Jar file to unsign " />
        <sequential>
            <copy toFile="@{jarFile}_MANIFEST.tmp">
                <resources>
                    <zipentry zipfile="@{jarFile}" name="META-INF/MANIFEST.MF" />
                </resources>
            </copy>

            <replaceregexp file="@{jarFile}_MANIFEST.tmp" match="\nName:(.+?)\nSH" replace="SH" flags="gis" byline="false" />
            <replaceregexp file="@{jarFile}_MANIFEST.tmp" match="SHA(.*)" replace="" flags="gis" byline="false" />
            <jar jarfile="@{jarFile}.tmp" manifest="@{jarFile}_MANIFEST.tmp">
                <zipfileset src="@{jarFile}">
                    <include name="**" />
                    <exclude name="META-INF/*.SF" />
                    <exclude name="META-INF/*.DSA" />
                    <exclude name="META-INF/*.RSA" />
                </zipfileset>
            </jar>
            <!-- Removing the temporary manifest -->
            <delete file="@{jarFile}_MANIFEST.tmp" />
            <!-- Swapping the original Jar file with the temporary one -->
            <move file="@{jarFile}.tmp" tofile="@{jarFile}" overwrite="true" />

        </sequential>
    </macrodef>
</project>