code: @Override
      public void execute () throws BuildException
      {
          // make sure everything was set up properly
          ensureSet(_target, "Must specify the path to the target bundle " +
                    "file via the 'target' attribute.");
          ensureSet(_mapfile, "Must specify the path to the component map " +
                    "file via the 'mapfile' attribute.");
          ensureSet(_actionDef, "Must specify the action sequence " +
                    "definitions via the 'actiondef' attribute.");
  
          // enumerate all the dirs/files to be processed
          List<Tuple<File,List<String>>> sourceDirs = Lists.newArrayList();
          for (FileSet fs : _filesets) {
              DirectoryScanner ds = fs.getDirectoryScanner(getProject());
              File fromDir = fs.getDir(getProject());
              String[] srcFiles = ds.getIncludedFiles();
              sourceDirs.add(Tuple.newTuple(fromDir, Arrays.asList(srcFiles)));
          }
  
          // do the deed!
          createBundler().execute(_root, _target, sourceDirs);
      }
docs: Performs the actual work of the task.