Add some JavaDoc to Fetchers

src/main/java/org/jabref/logic/importer/EntryBasedFetcher.java

@@ -6,7 +6,7 @@
 
 /**
  * Searches web resources for bibliographic information based on a {@link BibEntry}.
- * Useful to complete an existing entry with fetched information.
+ * Useful to <emph>complete</emph> an existing entry with fetched information.
  * May return multiple search hits.
  */
 public interface EntryBasedFetcher extends WebFetcher {

src/main/java/org/jabref/logic/importer/IdBasedFetcher.java

@@ -6,6 +6,7 @@
 
 /**
  * Searches web resources for bibliographic information based on an identifier.
+ * Examples are ISBN numbers and DOIs.
  */
 public interface IdBasedFetcher extends WebFetcher {
 

src/main/java/org/jabref/logic/importer/SearchBasedFetcher.java

@@ -15,6 +15,9 @@
 /**
  * Searches web resources for bibliographic information based on a free-text query.
  * May return multiple search hits.
+ * <p>
+ *    This interface is used for web resources which directly return BibTeX data ({@link BibEntry})
+ * </p>
  */
 public interface SearchBasedFetcher extends WebFetcher {
 

src/main/java/org/jabref/logic/importer/SearchBasedParserFetcher.java

@@ -13,12 +13,25 @@
 import org.apache.lucene.queryparser.flexible.core.nodes.QueryNode;
 
 /**
- * Provides a convenient interface for search-based fetcher, which follow the usual three-step procedure:
+ * Provides a convenient interface for search-based fetcher, which follows the usual three-step procedure:
  * <ol>
  *     <li>Open a URL based on the search query</li>
  *     <li>Parse the response to get a list of {@link BibEntry}</li>
  *     <li>Post-process fetched entries</li>
  * </ol>
+ * <p>
+ *     This interface is used for web resources which do NOT provide BibTeX data (@link {@link BibEntry)}.
+ *     JabRef's infrastructure to convert arbitrary input data to BibTeX is {@link Parser}.
+ * </p>
+ * <p>
+ *     This interface inherits {@link SearchBasedFetcher}, because the methods <code>performSearch</code> have to be provided by both.
+ *     As non-BibTeX web fetcher one could do "magic" stuff without this helper interface and directly use {@link WebFetcher}, but this is more work.
+ * </p>
+ * <p>
+ *     Note that this interface "should" be an abstract class.
+ *     However, Java does not support multi inheritance with classes (but with interfaces).
+ *     We need multi inheritance, because a fetcher might implement multiple query types (such as id fetching {@link IdBasedFetcher)}, complete entry {@link EntryBasedFetcher}, and search-based fetcher (this class).
+ * </p>
  */
 public interface SearchBasedParserFetcher extends SearchBasedFetcher {
 

src/main/java/org/jabref/logic/importer/fileformat/ACMPortalParser.java

@@ -71,8 +71,8 @@ public List<String> parseDoiSearchPage(InputStream stream) throws ParseException
             Elements doiHrefs = doc.select("div.issue-item__content-right > h5 > span > a");
 
             for (Element elem : doiHrefs) {
-                String fullSegement = elem.attr("href");
-                String doi = fullSegement.substring(fullSegement.indexOf("10"));
+                String fullSegment = elem.attr("href");
+                String doi = fullSegment.substring(fullSegment.indexOf("10"));
                 doiList.add(doi);
             }
         } catch (IOException ex) {