optimize opml export (fix #687)

src/main/java/com/commafeed/backend/opml/OPMLExporter.java

@@ -13,6 +13,9 @@ import com.commafeed.backend.dao.FeedSubscriptionDAO;
 import com.commafeed.backend.model.FeedCategory;
 import com.commafeed.backend.model.FeedSubscription;
 import com.commafeed.backend.model.User;
+import com.google.common.base.Function;
+import com.google.common.collect.Multimap;
+import com.google.common.collect.Multimaps;
 import com.rometools.opml.feed.opml.Attribute;
 import com.rometools.opml.feed.opml.Opml;
 import com.rometools.opml.feed.opml.Outline;
@@ -21,6 +24,14 @@ import com.rometools.opml.feed.opml.Outline;
 @Singleton
 public class OPMLExporter {
 
+	private static Long ROOT_CATEGORY_ID = new Long(-1);
+	private static final Function<FeedSubscription, Long> SUBSCRIPTION_TO_CATEGORYID = new Function<FeedSubscription, Long>() {
+		@Override
+		public Long apply(FeedSubscription sub) {
+			return sub.getCategory() == null ? ROOT_CATEGORY_ID : sub.getCategory().getId();
+		}
+	};
+
 	private final FeedCategoryDAO feedCategoryDAO;
 	private final FeedSubscriptionDAO feedSubscriptionDAO;
 
@@ -31,7 +42,7 @@ public class OPMLExporter {
 		opml.setCreated(new Date());
 
 		List<FeedCategory> categories = feedCategoryDAO.findAll(user);
-		List<FeedSubscription> subscriptions = feedSubscriptionDAO.findAll(user);
+		Multimap<Long, FeedSubscription> subscriptions = Multimaps.index(feedSubscriptionDAO.findAll(user), SUBSCRIPTION_TO_CATEGORYID);
 
 		// export root categories
 		for (FeedCategory cat : categories) {
@@ -41,17 +52,15 @@ public class OPMLExporter {
 		}
 
 		// export root subscriptions
-		for (FeedSubscription sub : subscriptions) {
+		for (FeedSubscription sub : subscriptions.get(ROOT_CATEGORY_ID)) {
-			if (sub.getCategory() == null) {
+			opml.getOutlines().add(buildSubscriptionOutline(sub));
-				opml.getOutlines().add(buildSubscriptionOutline(sub));
-			}
 		}
 
 		return opml;
 
 	}
 
-	private Outline buildCategoryOutline(FeedCategory cat, List<FeedSubscription> subscriptions) {
+	private Outline buildCategoryOutline(FeedCategory cat, Multimap<Long, FeedSubscription> subscriptions) {
 		Outline outline = new Outline();
 		outline.setText(cat.getName());
 		outline.setTitle(cat.getName());
@@ -60,10 +69,8 @@ public class OPMLExporter {
 			outline.getChildren().add(buildCategoryOutline(child, subscriptions));
 		}
 
-		for (FeedSubscription sub : subscriptions) {
+		for (FeedSubscription sub : subscriptions.get(cat.getId())) {
-			if (sub.getCategory() != null && sub.getCategory().getId().equals(cat.getId())) {
+			outline.getChildren().add(buildSubscriptionOutline(sub));
-				outline.getChildren().add(buildSubscriptionOutline(sub));
-			}
 		}
 		return outline;
 	}

src/test/java/com/commafeed/backend/opml/OPMLExporterTest.java

@@ -0,0 +1,141 @@
+package com.commafeed.backend.opml;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+import static org.mockito.Mockito.when;
+
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+
+import com.commafeed.backend.dao.FeedCategoryDAO;
+import com.commafeed.backend.dao.FeedSubscriptionDAO;
+import com.commafeed.backend.model.Feed;
+import com.commafeed.backend.model.FeedCategory;
+import com.commafeed.backend.model.FeedSubscription;
+import com.commafeed.backend.model.User;
+import com.rometools.opml.feed.opml.Opml;
+import com.rometools.opml.feed.opml.Outline;
+
+public class OPMLExporterTest {
+
+	@Mock
+	private FeedCategoryDAO feedCategoryDAO;
+	@Mock
+	private FeedSubscriptionDAO feedSubscriptionDAO;
+
+	private User user = new User();
+
+	private FeedCategory cat1 = new FeedCategory();
+	private FeedCategory cat2 = new FeedCategory();
+
+	private FeedSubscription rootFeed = newFeedSubscription("rootFeed", "rootFeed.com");
+	private FeedSubscription cat1Feed = newFeedSubscription("cat1Feed", "cat1Feed.com");
+	private FeedSubscription cat2Feed = newFeedSubscription("cat2Feed", "cat2Feed.com");
+
+	private List<FeedCategory> categories = new ArrayList<>();
+	private List<FeedSubscription> subscriptions = new ArrayList<>();
+
+	@Before
+	public void before_each_test() {
+		MockitoAnnotations.initMocks(this);
+
+		user.setName("John Doe");
+
+		cat1.setId(1l);
+		cat1.setName("cat1");
+		cat1.setParent(null);
+		cat1.setChildren(new HashSet<FeedCategory>());
+		cat1.setSubscriptions(new HashSet<FeedSubscription>());
+
+		cat2.setId(2l);
+		cat2.setName("cat2");
+		cat2.setParent(cat1);
+		cat2.setChildren(new HashSet<FeedCategory>());
+		cat2.setSubscriptions(new HashSet<FeedSubscription>());
+
+		cat1.getChildren().add(cat2);
+
+		rootFeed.setCategory(null);
+		cat1Feed.setCategory(cat1);
+		cat2Feed.setCategory(cat2);
+
+		cat1.getSubscriptions().add(cat1Feed);
+		cat2.getSubscriptions().add(cat2Feed);
+
+		categories.add(cat1);
+		categories.add(cat2);
+
+		subscriptions.add(rootFeed);
+		subscriptions.add(cat1Feed);
+		subscriptions.add(cat2Feed);
+	}
+
+	private Feed newFeed(String url) {
+		Feed feed = new Feed();
+		feed.setUrl(url);
+		return feed;
+	}
+
+	private FeedSubscription newFeedSubscription(String title, String url) {
+		FeedSubscription feedSubscription = new FeedSubscription();
+		feedSubscription.setTitle(title);
+		feedSubscription.setFeed(newFeed(url));
+		return feedSubscription;
+	}
+
+	@Test
+	public void generates_OPML_correctly() {
+		when(feedCategoryDAO.findAll(user)).thenReturn(categories);
+		when(feedSubscriptionDAO.findAll(user)).thenReturn(subscriptions);
+
+		Opml opml = new OPMLExporter(feedCategoryDAO, feedSubscriptionDAO).export(user);
+
+		List<Outline> rootOutlines = opml.getOutlines();
+		assertEquals(2, rootOutlines.size());
+		assertTrue(containsCategory(rootOutlines, "cat1"));
+		assertTrue(containsFeed(rootOutlines, "rootFeed", "rootFeed.com"));
+
+		Outline cat1Outline = getCategoryOutline(rootOutlines, "cat1");
+		List<Outline> cat1Children = cat1Outline.getChildren();
+		assertEquals(2, cat1Children.size());
+		assertTrue(containsCategory(cat1Children, "cat2"));
+		assertTrue(containsFeed(cat1Children, "cat1Feed", "cat1Feed.com"));
+
+		Outline cat2Outline = getCategoryOutline(cat1Children, "cat2");
+		List<Outline> cat2Children = cat2Outline.getChildren();
+		assertEquals(1, cat2Children.size());
+		assertTrue(containsFeed(cat2Children, "cat2Feed", "cat2Feed.com"));
+	}
+
+	private boolean containsCategory(List<Outline> outlines, String category) {
+		for (Outline o : outlines)
+			if (!"rss".equals(o.getType()))
+				if (category.equals(o.getTitle()))
+					return true;
+
+		return false;
+	}
+
+	private boolean containsFeed(List<Outline> outlines, String title, String url) {
+		for (Outline o : outlines)
+			if ("rss".equals(o.getType()))
+				if (title.equals(o.getTitle()) && o.getAttributeValue("xmlUrl").equals(url))
+					return true;
+
+		return false;
+	}
+
+	private Outline getCategoryOutline(List<Outline> outlines, String title) {
+		for (Outline o : outlines)
+			if (o.getTitle().equals(title))
+				return o;
+
+		return null;
+	}
+}