Using Ant's classpath in Eclipse

Question

I have an Ant build.xml file that works just fine on the command line: it compiles, builds the JAR, and I am able to execute the main method from the JAR just f

Answer 1

An alternative to perl is to use an embedded groovy task:

<project name="demo" default="eclipse-files">

    <property name="src.dir"     location="src"/>
    <property name="classes.dir" location="build/classes"/>

    <path id="dep.runtime">
       <fileset dir="${lib}"       includes="**/*.jar"/>
       <fileset dir="${hive-util}" includes="**/*.jar"/>
       <fileset dir="${hpdb}"      includes="**/*.jar"/>
       <fileset dir="${static}"    includes="**/*.jar"/>
    </path>

    <target name="bootstrap">
        <mkdir dir="${user.home}/.ant/lib"/>
        <get dest="${user.home}/.ant/lib/groovy-all.jar" src="http://search.maven.org/remotecontent?filepath=org/codehaus/groovy/groovy-all/2.1.4/groovy-all-2.1.4.jar"/>
    </target>

    <target name="eclipse-files">
        <taskdef name="groovy" classname="org.codehaus.groovy.ant.Groovy"/>
        <groovy>
            import groovy.xml.MarkupBuilder

            project.log "Creating .classpath"

            new File(".classpath").withWriter { writer ->
                def xml = new MarkupBuilder(writer)

                xml.classpath() {
                    classpathentry(kind:"src",    path:properties["src.dir"])
                    classpathentry(kind:"output", path:properties["classes.dir"])
                    classpathentry(kind:"con",    path:"org.eclipse.jdt.launching.JRE_CONTAINER")

                    project.references."dep.runtime".each {
                        classpathentry(kind:"lib", path:it)
                    }
                }
            }
        </groovy>
    </target>

    <target name="clean">
        <delete file=".classpath"/>
    </target>

</project>

Notes:

• The bootstrap target will download the 3rd party groovy jar (No dependency on perl)
• Groovy can access the "dep.runtime" ANT path directly and iterate over its contents
• Groovy has excellent support for writing XML files.

The following answer is similar and additionally generates the Eclipse .project file.

• Using Apache Ivy with netbeans

Answer 2

I came up with the following workaround, inspired by the link provided by @leeand00.

First, I wrote a simple Perl script (called genClasspath.pl) that generates the .classpath file that Eclipse uses.

#!/usr/bin/perl
use strict;

if (@ARGV != 2) {
  print STDERR "Usage: $0 OUTFILE CLASSPATHSTRING\n";
  print STDERR "e.g., $0 .classpath path1:path2:path3\n";
  exit 1;
}

my $OUTFILE         = $ARGV[0];
my $CLASSPATHSTRING = $ARGV[1];

open my $out_fh, '>', $OUTFILE or die "Couldn't open output file: $!";

print $out_fh q{<?xml version="1.0" encoding="UTF-8"?>
<classpath>
    <classpathentry kind="src" path="src"/>
    <classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER"/>
    <classpathentry kind="output" path="build"/>
};

my @libs = split(":", $CLASSPATHSTRING);
foreach my $thisLib (@libs){
    print $out_fh "    <classpathentry kind=\"lib\" path=\"$thisLib\"/>\n";
}
print $out_fh "</classpath>\n";

Then, I have my build.xml file call this script with the content of dep.runtime:

<target name="compile" depends="init">
    <javac srcdir="${src}" destdir="${build}" debug="on" includeantruntime="false">
        <classpath refid="dep.runtime" />
    </javac>

    <property name="myclasspath" refid="dep.runtime"/>

    <exec dir="." executable="../../scripts/genClasspath.pl" os="Linux">
        <arg value=".classpath"/>
        <arg value="${myclasspath}"/>
    </exec>

</target>

The only catch is that I need to run Ant on the command line at least once before I open the project in Eclipse. But when I do, Eclipse is able to compile and execute my project just fine, since the classpath is exactly the same as Ant's.