3.3 Getting Information

3.3.1 Locations

So, where is my specific configuration looking for its contents?

To see where a Configuration instance gets its contents from, you can use getSourceLocations() like this:

 System.out.println("config locations: ");
 for (ConfigLocation location : cfg.getSourceLocations())
     System.out.println("\t" + location.getScope() + "\t" + location.getURI("entry", null));

And where is the overall mConfig factory instance looking, in general? There is getSearchList() from ConfigFactory.

 System.out.println("searchList: ");
 for (ConfigLocation location : searchList)
     System.out.println("\t" + location.getScope() + "\t" + location.getURI("entry", null));

Depending on your use case, you'll want different parts of the ConfigLocation entries. Above is just a little text dump.

3.3.2 Legacy support: BLOBs, and where to put files?

Use Configuration mechanisms where possible; this enables all the features, including scheme checking, network storage, and so on.

3.3.2.1 Raw Files (Text and Binary)

You may need to access the entire content of a file as a single String or byte array. mConfig provides two specialized formats for this purpose: text_file and binary_file.

Reading a text file as a single String: By using the text_file format, the entire file content is read into a single entry with an empty key "".

try (ConfigFactory factory = ConfigFactoryBuilder.create("myCompany", "myApplication")
        .setFeature(ConfigFeature.FILE_FORMAT_READING_PRIORITIES, List.of("text_file"))
        .build())
    {
    Configuration cfg = factory.getConfiguration("myTextFile");
    String content = cfg.getString("");
    }

Reading a binary file as a byte array: The binary_file format works similarly but provides the content as a byte array.

try (ConfigFactory factory = ConfigFactoryBuilder.create("myCompany", "myApplication")
        .setFeature(ConfigFeature.FILE_FORMAT_READING_PRIORITIES, List.of("binary_file"))
        .build())
    {
    Configuration cfg = factory.getConfiguration("myBinaryFile");
    byte[] content = cfg.getBytes("");
    }

3.3.2.2 Hierarchical BLOBs

In modern formats like JSON and YAML, binary data can be part of the hierarchical structure.

JSON (Base64): If a ConfigScheme defines a key as type BYTES, mConfig will automatically decode a Base64-encoded string in a JSON file.

YAML (!!binary): YAML supports binary data natively using the !!binary tag. mConfig will correctly retrieve these as byte arrays.

byte[] data = cfg.getBytes("server/certificate");

3.3.2.3 Legacy BLOBs

The second fallback for supporting legacy applications is that you can get filesystem paths for a given Scope. If there are several for the same Scope, mConfigUtil will prioritize the most specific entry, and prefer those which exist already over those which would need to be created.

Path localPath = ConfigUtil.whereToPutMyFiles(configFactory, ConfigScope.USER, false);

But please, consider using regular mConfig functionality instead where possible.