components/camel-rss/src/main/java/org/apache/camel/component/rss/UpdatedDateFilter.java

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.camel.component.rss;

import java.util.Date;
import java.util.Map;

import com.sun.syndication.feed.synd.SyndEntry;
import org.apache.camel.component.feed.EntryFilter;
import org.apache.camel.component.feed.FeedEndpoint;
import org.apache.camel.util.LRUCache;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Filters out all entries which occur before the last time of the entry we saw
 * (assuming entries arrive sorted in order).
 */
public class UpdatedDateFilter implements EntryFilter {

    private static final Logger LOG = LoggerFactory.getLogger(UpdatedDateFilter.class);
    private Date lastUpdate;
    // use a LRU so we only keep the last 1000 elements to avoid growing to large
    private Map<Integer, Integer> entriesForLastUpdate = new LRUCache<Integer, Integer>(1000);

    public UpdatedDateFilter(Date lastUpdate) {
        this.lastUpdate = lastUpdate;
    }

    public boolean isValidEntry(FeedEndpoint endpoint, Object feed, Object entry) {
        Date updated = ((SyndEntry) entry).getUpdatedDate();
        if (updated == null) {
            // never been updated so get published date
            updated = ((SyndEntry) entry).getPublishedDate();
        }
        if (updated == null) {
            LOG.debug("No updated time for entry so assuming its valid: entry=[{}]", entry);
            return true;
        }
        if (lastUpdate != null) {
            if (lastUpdate.after(updated)) {
                LOG.debug("Entry is older than lastupdate=[{}], no valid entry=[{}]", lastUpdate, entry);
                return false;
            } else {
                Integer hash = entry.hashCode();
                if (lastUpdate.equals(updated)) {
                    if (entriesForLastUpdate.containsKey(hash)) {
                        LOG.debug("Already processed entry=[{}]", entry);
                        return false;
                    }
                } else {
                    entriesForLastUpdate.clear();
                }
                entriesForLastUpdate.put(hash, hash);
            }
        }
        lastUpdate = updated;
        return true;
    }
}