// Model initialization
fileDirty = false;
dirtyTypeNameHash = new HashSet();
descriptorCAS = new DescriptorTCAS(this);
allTypes = new AllTypes(this);
definedTypesWithSupers = new DefinedTypesWithSupers(this);
// reasonable initial values
aeDescription = UIMAFramework.getResourceSpecifierFactory().createAnalysisEngineDescription();
typeSystemDescription = null;
importedTypeSystemDescription = null;