/**
* Licensed to The Apereo Foundation under one or more contributor license
* agreements. See the NOTICE file distributed with this work for additional
* information regarding copyright ownership.
*
*
* The Apereo Foundation licenses this file to you under the Educational
* Community 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://opensource.org/licenses/ecl2.txt
*
* 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.opencastproject.feed.impl;
import org.opencastproject.feed.api.Feed.Type;
import org.opencastproject.feed.api.FeedGenerator;
import org.opencastproject.search.api.SearchQuery;
import org.opencastproject.search.api.SearchResult;
import org.opencastproject.search.impl.solr.Schema;
import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.Properties;
/**
* This feed generator creates a feed for the latest episodes across a set of series as specified by the service
* property <code>feed.series</code>.
* <p>
* The service will answer requests matching the service property <code>feed.selector</code> as the first query argument
* passed to the {@link #accept(String[])} method.
*/
public class AggregationFeedService extends AbstractFeedService implements FeedGenerator {
/** Logging facility */
private static Logger logger = LoggerFactory.getLogger(AggregationFeedService.class);
/** Property key for the series */
private static final String PROP_SERIES = "feed.series";
/** The solr query */
private String solrQuery = null;
/**
* {@inheritDoc}
*
* @see org.opencastproject.feed.api.FeedGenerator#accept(java.lang.String[])
*/
public boolean accept(String[] query) {
if (solrQuery == null) {
logger.warn("{} denies to handle request for {} since query is still undefined", this, query);
return false;
}
return super.accept(query);
}
/**
* {@inheritDoc}
*
* @see org.opencastproject.feed.impl.AbstractFeedGenerator#loadFeedData(org.opencastproject.feed.api.Feed.Type,
* java.lang.String[], int, int)
*/
protected SearchResult loadFeedData(Type type, String[] query, int limit, int offset) {
try {
SearchQuery q = createBaseQuery(type, limit, offset);
q.withQuery(solrQuery);
return searchService.getByQuery(q);
} catch (Exception e) {
logger.error("Cannot retrieve result for aggregated feed", e);
return null;
}
}
/**
* Sets the series that are to be aggregated when creating the feed.
*
* @param series
* the series identifier
*/
public void setSeries(String[] series) {
if (series == null || series.length == 0)
throw new IllegalArgumentException("Series cannot be null or empty");
// Create the solr query for the series
StringBuffer q = new StringBuffer();
q.append(Schema.DC_IS_PART_OF);
q.append(":(");
for (String s : series) {
q.append(s).append(" ");
}
q.append(")");
// Store the query
solrQuery = q.toString();
}
/**
* {@inheritDoc}
*
* @see org.opencastproject.feed.impl.AbstractFeedService#initialize(java.util.Properties)
*/
@Override
public void initialize(Properties properties) {
String series = (String) properties.get(PROP_SERIES);
if (series != null && !"".equals(series)) {
String[] seriesIds = series.split(",");
for (int i = 0; i < seriesIds.length; i++) {
seriesIds[i] = StringUtils.trim(seriesIds[i]);
}
setSeries(seriesIds);
logger.debug("Configuring aggregation feed with series {}", series);
}
super.initialize(properties);
}
}