Introducing Spring Framework

Chapter 8 ■ Give Advice to Your Spring Application
public class SearchEngineService implements SearchEngine {
private static final Logger log = LoggerFactory.getLogger(SearchEngineService.class);
private DocumentDAO documentDAO;
public SearchEngineService(){
if(log.isDebugEnabled())
log.debug("SearchEngineService created: " + this);
}
public DocumentDAO getDocumentDAO() {
return documentDAO;
}
public void setDocumentDAO(DocumentDAO documentDAO) {
if(log.isDebugEnabled())
log.debug("Document DAO set: " + documentDAO);
}
this.documentDAO = documentDAO;
public List findByType(Type documentType) {
if(log.isDebugEnabled())
log.debug("Start Params: " + documentType);
List result = new ArrayList();
for(Document doc : listAll()){
if(doc.getType().getName().equals(documentType.getName()))
result.add(doc);
}
}
if(log.isDebugEnabled())
log.debug("End Result: " + result);
return result;
public List listAll() {
if(log.isDebugEnabled())
log.debug("Start Params: ");
List result = Arrays.asList(documentDAO.getAll());
if(log.isDebugEnabled())
log.debug("End Result: " + result);
return result;
}
}
In Listing 8-1 you are using the “if” statement because debugging is enabled and it is calling the log.debug
method. But take a closer look; those “if” statements are in every method: in the constructor, in the findByType,
listAll, and in the setter of the DocumentDAO. Also these statements are in different classes as well. This is called
tangling and scattering code, as shown in Figure 8-1.
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