new setting for deleting old entries (fix #524)

src/main/java/com/commafeed/CommaFeedConfiguration.java

@@ -110,6 +110,10 @@ public class CommaFeedConfiguration extends Configuration {
 		@Min(0)
 		private int keepStatusDays;
 
+		@NotNull
+		@Min(0)
+		private int maxFeedCapacity;
+
 		@NotNull
 		@Min(0)
 		private int refreshIntervalMinutes;

src/main/java/com/commafeed/CommaFeedModule.java

@@ -15,6 +15,7 @@ import com.commafeed.backend.favicon.AbstractFaviconFetcher;
 import com.commafeed.backend.favicon.DefaultFaviconFetcher;
 import com.commafeed.backend.favicon.FacebookFaviconFetcher;
 import com.commafeed.backend.favicon.YoutubeFaviconFetcher;
+import com.commafeed.backend.task.OldEntriesCleanupTask;
 import com.commafeed.backend.task.OldStatusesCleanupTask;
 import com.commafeed.backend.task.OrphansCleanupTask;
 import com.commafeed.backend.task.ScheduledTask;
@@ -49,6 +50,7 @@ public class CommaFeedModule extends AbstractModule {
 
 		Multibinder<ScheduledTask> taskMultibinder = Multibinder.newSetBinder(binder(), ScheduledTask.class);
 		taskMultibinder.addBinding().to(OldStatusesCleanupTask.class);
+		taskMultibinder.addBinding().to(OldEntriesCleanupTask.class);
 		taskMultibinder.addBinding().to(OrphansCleanupTask.class);
 	}
 }

src/main/java/com/commafeed/backend/dao/FeedEntryDAO.java

@@ -1,11 +1,13 @@
 package com.commafeed.backend.dao;
 
-import java.util.Date;
 import java.util.List;
 
 import javax.inject.Inject;
 import javax.inject.Singleton;
 
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+
 import org.apache.commons.codec.digest.DigestUtils;
 import org.hibernate.SessionFactory;
 
@@ -13,6 +15,9 @@ import com.commafeed.backend.model.Feed;
 import com.commafeed.backend.model.FeedEntry;
 import com.commafeed.backend.model.QFeedEntry;
 import com.google.common.collect.Iterables;
+import com.google.common.collect.Lists;
+import com.mysema.query.Tuple;
+import com.mysema.query.types.expr.NumberExpression;
 
 @Singleton
 public class FeedEntryDAO extends GenericDAO<FeedEntry> {
@@ -30,10 +35,27 @@ public class FeedEntryDAO extends GenericDAO<FeedEntry> {
 		return Iterables.getFirst(list, null);
 	}
 
-	public int delete(Date olderThan, int max) {
-		List<FeedEntry> list = newQuery().from(entry).where(entry.inserted.lt(olderThan)).limit(max).list(entry);
+	public List<FeedCapacity> findFeedsExceedingCapacity(long maxCapacity, long max) {
+		List<FeedCapacity> list = Lists.newArrayList();
+		NumberExpression<Long> count = entry.id.countDistinct();
+		List<Tuple> tuples = newQuery().from(entry).groupBy(entry.feed).having(count.gt(maxCapacity)).limit(max).list(entry.feed.id, count);
+		for (Tuple tuple : tuples) {
+			list.add(new FeedCapacity(tuple.get(entry.feed.id), tuple.get(count)));
+		}
+		return list;
+	}
+
+	public int deleteOldEntries(Long feedId, long max) {
+		List<FeedEntry> list = newQuery().from(entry).where(entry.feed.id.eq(feedId)).orderBy(entry.updated.asc()).limit(max).list(entry);
 		int deleted = list.size();
 		delete(list);
 		return deleted;
 	}
+
+	@AllArgsConstructor
+	@Getter
+	public static class FeedCapacity {
+		private Long id;
+		private Long capacity;
+	}
 }

src/main/java/com/commafeed/backend/service/DatabaseCleaningService.java

@@ -1,9 +1,7 @@
 package com.commafeed.backend.service;
 
-import java.util.Calendar;
 import java.util.Date;
 import java.util.List;
-import java.util.concurrent.TimeUnit;
 
 import javax.inject.Inject;
 import javax.inject.Singleton;
@@ -16,6 +14,7 @@ import org.hibernate.SessionFactory;
 import com.commafeed.backend.dao.FeedDAO;
 import com.commafeed.backend.dao.FeedEntryContentDAO;
 import com.commafeed.backend.dao.FeedEntryDAO;
+import com.commafeed.backend.dao.FeedEntryDAO.FeedCapacity;
 import com.commafeed.backend.dao.FeedEntryStatusDAO;
 import com.commafeed.backend.dao.UnitOfWork;
 import com.commafeed.backend.model.Feed;
@@ -75,23 +74,37 @@ public class DatabaseCleaningService {
 		return total;
 	}
 
-	public long cleanEntriesOlderThan(long value, TimeUnit unit) {
-		final Calendar cal = Calendar.getInstance();
-		cal.add(Calendar.MINUTE, -1 * (int) unit.toMinutes(value));
-
+	public long cleanEntriesForFeedsExceedingCapacity(final int maxFeedCapacity) {
 		long total = 0;
-		int deleted = 0;
-		do {
-			deleted = new UnitOfWork<Integer>(sessionFactory) {
+		while (true) {
+			List<FeedCapacity> feeds = new UnitOfWork<List<FeedCapacity>>(sessionFactory) {
 				@Override
-				protected Integer runInSession() throws Exception {
-					return feedEntryDAO.delete(cal.getTime(), BATCH_SIZE);
+				protected List<FeedCapacity> runInSession() throws Exception {
+					return feedEntryDAO.findFeedsExceedingCapacity(maxFeedCapacity, BATCH_SIZE);
 				}
 			}.run();
-			total += deleted;
-			log.info("removed {} entries", total);
-		} while (deleted != 0);
-		log.info("cleanup done: {} entries deleted", total);
+
+			if (feeds.isEmpty()) {
+				break;
+			}
+
+			for (final FeedCapacity feed : feeds) {
+				long remaining = feed.getCapacity() - maxFeedCapacity;
+				do {
+					final long rem = remaining;
+					int deleted = new UnitOfWork<Integer>(sessionFactory) {
+						@Override
+						protected Integer runInSession() throws Exception {
+							return feedEntryDAO.deleteOldEntries(feed.getId(), Math.min(BATCH_SIZE, rem));
+						};
+					}.run();
+					total += deleted;
+					remaining -= deleted;
+					log.info("removed {} entries for feeds exceeding capacity", total);
+				} while (remaining > 0);
+			}
+		}
+		log.info("cleanup done: {} entries for feeds exceeding capacity deleted", total);
 		return total;
 	}
 

src/main/java/com/commafeed/backend/task/OldEntriesCleanupTask.java

@@ -0,0 +1,43 @@
+package com.commafeed.backend.task;
+
+import java.util.concurrent.TimeUnit;
+
+import javax.inject.Inject;
+import javax.inject.Singleton;
+
+import lombok.RequiredArgsConstructor;
+
+import com.commafeed.CommaFeedConfiguration;
+import com.commafeed.backend.service.DatabaseCleaningService;
+
+@RequiredArgsConstructor(onConstructor = @__({ @Inject }))
+@Singleton
+public class OldEntriesCleanupTask extends ScheduledTask {
+
+	private final CommaFeedConfiguration config;
+	private final DatabaseCleaningService cleaner;
+
+	@Override
+	public void run() {
+		int maxFeedCapacity = config.getApplicationSettings().getMaxFeedCapacity();
+		if (maxFeedCapacity > 0) {
+			cleaner.cleanEntriesForFeedsExceedingCapacity(maxFeedCapacity);
+		}
+	}
+
+	@Override
+	public long getInitialDelay() {
+		return 5;
+	}
+
+	@Override
+	public long getPeriod() {
+		return 60;
+	}
+
+	@Override
+	public TimeUnit getTimeUnit() {
+		return TimeUnit.MINUTES;
+	}
+
+}

src/main/java/com/commafeed/backend/task/OldStatusesCleanupTask.java

@@ -28,7 +28,7 @@ public class OldStatusesCleanupTask extends ScheduledTask {
 
 	@Override
 	public long getInitialDelay() {
-		return 10;
+		return 15;
 	}
 
 	@Override

src/main/java/com/commafeed/backend/task/OrphansCleanupTask.java

@@ -23,7 +23,7 @@ public class OrphansCleanupTask extends ScheduledTask {
 
 	@Override
 	public long getInitialDelay() {
-		return 5;
+		return 10;
 	}
 
 	@Override