Reader reader = DSLAdapter.getDSLContent(content, dslRuleEditor.getResource());
if (reader == null) {
throw new IllegalArgumentException("Could not find dsl definition.");
}
DSLMappingFile mapping = new DSLTokenizedMappingFile();
mapping.parseAndLoad(reader);
reader.close();
expander.addDSLMapping(mapping.getMapping());
expander.expand(content);
// if translation succeeds, change to drl viewer
drlRuleViewer.setInput(getEditorInput());