According to our experience a lot of users, do not care a lot about formats and don't want to. Users often don't know the format of a corpus, they just want to bring into the format, the tool they are using, needs. Therefore Pepper provides a possibility to automatically detect the source format of a corpus. Unfortunately this task highly depends on the format and the module processing the format. That makes the detection very individual and to a task of the modules implementor, so you. The mechanism of automatic detection is not a mandatory task, but it is very useful, what makes it recommended.

The interface org.corpus_tools.pepper.modules.PepperImporter defines the method org.corpus_tools.pepper.modules.PepperImporter.isImportable(URI corpusPath) which can be overridden. The passed URI locates the entry point of the entire corpus as given with the Pepper workflow (it points to the same location as org.corpus_tools.pepper.common.CorpusDesc.getCorpusPath()). Depending on the formats you want to support with your importer the detection can be very different. In the simplest case it only is necessary to search through the files at the given location (or to recursively traverse through directories, in case the location points to a directory), and to read their header section. For instance some formats like the xml formats PAULA (http://www.sfb632.uni-potsdam.de/en/paula.html) or TEI (http://www.tei-c.org/Guidelines/P5/) start with a header section like:

<?xml version="1.0" standalone="no"?>
<paula version="1.0">
<!-- ... -->

or

<?xml version="1.0" encoding="UTF-8"?>
<!-- ... -->
<TEI xmlns="http://www.tei-c.org/ns/1.0">
<!-- ... -->

The formats, where it fits reading only the first lines make automatic detection very easy. The method isImportable(URI corpusPath) shall return 1 if the corpus is importable by your importer, 0 if the corpus is not importable or a value between 0 < X < 1, if no definitive answer is possible. The default implementation returns 'null', what means that the method is not overridden and Pepper ignores the module in automatic detection phase.