private String createTempindexDir(SolrCore core,String tmpIdxDirName){
  String tmpIdxDir=core.getDataDir() + tmpIdxDirName;
  return tmpIdxDir;
}

private String createTempindexDir ( SolrCore core , String tmpIdxDirName ) { String tmpIdxDir = core . getDataDir ( ) + tmpIdxDirName ; return tmpIdxDir ; }
all the files are copied to a temp dir first
