5

I'm developing a jee application which has to look at two files in order to load configuration parameters. Both files are properties-like files.

The first one contains a default configuration properties and the other one overrides them. So the first one is read-only and the other one can be modified. I need to react and update changes made on second configuration file.

I've take a look on several resources:

I've not been able to figure out what and how to make configuration strategy with commons-configuration2.

Up to now, I've been able to read from one configuration file:

FileBasedConfigurationBuilder<PropertiesConfiguration> builder =
    new FileBasedConfigurationBuilder<PropertiesConfiguration>(PropertiesConfiguration.class)
        .configure(new Parameters().properties()
            .setFileName(ConfigurationResources.PROPERTIES_FILEPATH)
            .setThrowExceptionOnMissing(true)
            .setListDelimiterHandler(new DefaultListDelimiterHandler(';'))
            .setIncludesAllowed(false));

Any ideas?

Jordi
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2 Answers2

3

You need CombinedConfiguration. Here is the sample code

Parameters params = new Parameters();
CombinedConfigurationBuilder builder = new CombinedConfigurationBuilder()
    .configure(params.fileBased().setFile(new File("configuration.xml")));
CombinedConfiguration cc = builder.getConfiguration();

Here configuration.xml file would contain the list of property files 

<configuration systemProperties="systemProperties.xml">
  <!-- Load the system properties -->
  <system/>
  <!-- Now load the config file, using a system property as file name -->
  <properties fileName="myprops1.properties"/>

  <properties fileName="myprops2.propert"/>
</configuration>

This documentation on Combined Configuration will be really helpful

100rabh
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3
Parameters params = new Parameters();

FileBasedConfigurationBuilder<FileBasedConfiguration> config1 = new FileBasedConfigurationBuilder<FileBasedConfiguration>(
        PropertiesConfiguration.class)
                .configure(params.properties().setFileNamesetFileName("file1.properties")));
FileBasedConfigurationBuilder<FileBasedConfiguration> config2 = new FileBasedConfigurationBuilder<FileBasedConfiguration>(
        PropertiesConfiguration.class).configure(params.properties().setFileName("default_file2.properties"));


CombinedConfiguration config = new CombinedConfiguration(new OverrideCombiner());
config.addConfiguration(config1.getConfiguration());//this overrides config2
config.addConfiguration(config2.getConfiguration());
return config;

This is something I have used in my project to create a combined configuration. A combined configuration naturally creates a hierarchy of configurations taken from different or same source. For example you could also write something like : FileBasedConfigurationBuilder<FileBasedConfiguration> config2 = new FileBasedConfigurationBuilder<FileBasedConfiguration>( PropertiesConfiguration.class).configure(params.properties()‌​.setFileName(System.‌​getProperty("default‌​_file2.properties"))‌​);

The FileBasedConfigurationBuilder can be substituted with any kind of configuration you may like. Refer to the link https://commons.apache.org/proper/commons-configuration/apidocs/org/apache/commons/configuration2/builder/BasicConfigurationBuilder.html

user6622569
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