Help with XMLConfiguration

[Mike Bates]

I am looking at using the Apache Commons Configuration with XML. When I save the configuration it writes out the XML twice. I know I am doing something wrong but can't figure it out. The other odd thing is that it puts out cntrl-Ms on each line (I removed them from the output.)

Here is the XML for input {readconfig4.xml}:

<?xml version="1.0" encoding="UTF-8"?>
<!--
    Document   : readconfig4.xml
    Created on : October 3, 2009, 4:54 PM
    Author     : 
    Description:
        Purpose of the document follows.
-->
<config>
    <comment>info</comment>
<comm>
    <port>/dev/ttyS0</port>
    <buad>19200</buad>
    <parity>none</parity>
    <stopbits>1</stopbits>
    <bits>8</bits>
    <flwcontrol>none</flwcontrol>
</comm>
</config>

Here is my test code:

import org.apache.commons.configuration.XMLConfiguration;
import org.apache.commons.configuration.ConfigurationException;

public class ReadXMLConfig {

    private static XMLConfiguration config;

    public static void main(String[] args) {

        try {
            config = new XMLConfiguration("readconfig4.xml");
            config.load();
            //Object obj = config.getProperty("database.url");
            System.out.println("URL: "+config.getString("comm.port"));
            // do something with config
            config.setProperty("comm.port", "COM1");
            config.setFileName("readconfigout4.xml");
            config.save();
        } catch(ConfigurationException cex) {
            // something went wrong, e.g. the file was not found
            cex.printStackTrace();
        }
    }

}

And here is the output {readconfigout4.xml}:

<?xml version="1.0" encoding="UTF-8"?>
<!--
    Document   : readconfig4.xml
    Created on : October 3, 2009, 4:54 PM
    Author     : 
    Description:
        Purpose of the document follows.
-->
<config>
<comment>info</comment>
<comm>
    <port>COM1</port>
    <buad>19200</buad>
    <parity>none</parity>
    <stopbits>1</stopbits>
    <bits>8</bits>
    <flwcontrol>none</flwcontrol>
</comm>
<comment>info</comment>
<comm>
<buad>19200</buad>
<parity>none</parity>
<stopbits>1</stopbits>
<bits>8</bits>
<flwcontrol>none</flwcontrol>
</comm>
</config>

Any thoughts or guidance would be great.

Thanks
Mike

[Paul Clapham]

I checked the API documentation for that XMLConfiguration constructor. It says:

Creates and loads the XML configuration from the specified resource.

Note the words "and loads" there.

As for the "cntrl-M" characters, those are also known as "carriage return" characters. They are perfectly legal whitespace in XML documents. Perhaps this software uses the system default line-endings when it writes XML, and if so then that's what you would see if you ran it on a Windows platform but not on a Unix platform.

(It's more traditional for XML software to use only "line feed" characters on all platforms, since XML parsers are supposed to normalize away the "carriage return" characters, but there's nothing wrong with either version.)

[Leandro Coutinho]

Paul Clapham wrote:Note the words "and loads" there.

I was trying to solve and it was a simple solution. :banghead:

[Mike Bates]

So what you are saying is even though there is a save method

void save(Writer writer)
Save the configuration to the specified writer.

This does not work as I would expect. I thought this would save the configuration?

Mike

[Leandro Coutinho]

Mike Bates wrote:So what you are saying is even though there is a save method

void save(Writer writer)
Save the configuration to the specified writer.

This does not work as I would expect. I thought this would save the configuration?

Mike

You need to remove this part: config.load();

[Mike Bates]

Ok, I understand now (a bit dense this weekend.)

So the XMLConfiguration does a config and load. The config.load I had in place, loaded the information again.

Thanks

[Paul Clapham]

Mike Bates wrote:Ok, I understand now (a bit dense this weekend.)

No, it was just that you had already decided (incorrectly) where the problem was located. That makes it difficult to look elsewhere for the problem, even when somebody specifically points to another location.