DOMS object model creation from tree

General description

The goal of this document is to describe the work of transforming data files and accompanying metadata files in a tree structure on disk to a Content-Model less object tree in DOMS.

For this to be generic some assumptions needs to be taken:

• Data files and metadata files that belongs together have the same prefix
• Data files can be recognised by their file suffix.
• Checksum files is supposed to be represented as objects, but as a property of an object. They will thus be skipped as objects in the tree, but used for creation in the creation of the object they belong to.

General rules:

1. Directories are treated as a "hasPart" relation to a new object.
   
   1. The name of the relation is the directory name
   2. The new object's label is the path of the directory.
2. A data file is a file containing data. The actual data is stored outside DOMS.
3. A metadata file is a file containing metadata. The file is stored inside DOMS.
4. A grouping of files (files having a common prefix) is represented as a object with:
   1. Datastreams for each metadata file
   2. "hasFile" relations to data files

Pseudo code expressing the above rules

The following pseudo code is meant to express the above rules on a more formal basis.

In the codes, the methods:

• groupByPrefix(): returns an object which groups files by their common prefix.
• isDataFile(): returns a boolean telling if the given file is a datafile. 

void handleDir(myDir, domsParentObject) {
  thisDirObject = new Object(label = myDir.getName());
  domsParentObject.addHasPart(object = thisDirObject, relationName = myDir.getPath());
  for(dir in myDir.getDirectories()) {
    handleDir(dir, thisDirObject);
  }
  
  handleFiles(myDir.getFiles(), thisDirObject);
}

void handleFiles(myFiles, dirParentObject) {
  for(group in groupByPrefix(myFiles)) {
    if(group.size == 1) {
      handleFile(group.get(0), dirParentObject);
    } else {
      addHasPart(group, dirParentObject);
    }
  }
}

void handleFile(file, parentObject) {
  if(isDataFile(file)) {
    addHasFile(file, parentObject);
  } else {
    addDataStream(file, parentObject);
  }
}

void addHasPart(fileGroup, dirParentObject) {
  thisPartObject = new Object(label = fileGroup.getPrefix());
  dirParentObject.addHasPart(object = thisPartObject, relationName = fileGroup.getPrefix());
  
  for(file in fileGroup) {
    handleFile(file, thisPartObject);
  }
}