Apache Ant "which" scriptdef

ant-which.xml

<property environment="env" />
<property name="env.PATH" value="${env.Path}" /><!-- because windows -->

<scriptdef name="which" language="javascript">
  <attribute name="command" />
  <attribute name="property" />
  <![CDATA[
    var cmd   = attributes.get("command")  || "";
    var prop  = attributes.get("property") || "";

    if ("" == cmd ) throw new Error("The attribute 'command' is required for the Which task.");
    if ("" == prop) throw new Error("The attribute 'property' is required for the Which task.");

    var path  = project.getProperty("env.PATH")    || "";
    var exts  = project.getProperty("env.PATHEXT") || ""; // only windows will have this

    var uri   = null;
    var res   = cmd + ".uri";

    var which = project.createTask("whichresource");
    which.setProperty(res);
    which.createClasspath().createPath().setPath(path);

    for each (var ext in exts.split(";")) {
      which.setResource(cmd + ext);
      which.execute();
      uri = project.getProperty(res);
      if (null !== uri) {
        importClass(Packages.org.apache.tools.ant.util.FileUtils);
        project.setNewProperty(prop, FileUtils.getFileUtils().fromURI(uri));
        break;
      }
    }
  ]]>
</scriptdef>