Krdytkyu

Task

I want to handle a XML file from a source I cannot influence. All XML files from this source have the "problem" that the < and >symbols are represented by < and > respectively.

Problem

My program only sees the file on the local hard drive and is not influencing the genration of this file. The file size will never exceed 50 MiB. I encountered problems when parsing this XML file with the java DOM library and therefore decided to replace all occurences of < and > with their corresponding symbols.

Concern/Current solution

What I am concerned with, however, is the integrity of the file. So I came up with a solution using a temporary file.

private void modifyLog() throws FileNotFoundException, IOException {

    Path logFile = Paths.get(ConfigFileLoader.getInstance().getLogFileOption());

    if(!Files.isRegularFile(logFile)) {

        throw new FileNotFoundException("Log '" + logFile.toString() + "' not modified.");

    } else {

        Path tmpFile = Files.createTempFile("log_modified", "xml.tmp");



        try (FileWriter fw = new FileWriter(tmpFile.toAbsolutePath().toString())) {

            try (BufferedReader br = new BufferedReader(new FileReader(logFile.toAbsolutePath().toString()))) {

                while(br.ready()) {

                    fw.write(br.readLine().replaceAll("&lt;", "<").replaceAll("&gt;", ">"));

                    fw.write(System.lineSeparator());

                }

            }

        }



        Files.copy(tmpFile, logFile, StandardCopyOption.REPLACE_EXISTING);

        PackageBase.logger.trace("Successfully modified logfile at '{}'", logFile.toAbsolutePath().toString());

    }

}

Question

Does the above code snippet make sure that either the original file remains untouched or all strings mentioned above got replaced in the original file?

What do you think about the usage of the try-with-resources block?

Although the performance has already proven to be good enough for my application, could/should I further improve the runtime of the replacement process?