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/*
* Copyright (C) 2015 The Android Open Source Project
*
* Licensed 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 com.android.tv.recommendation;
import java.util.List;
public class FavoriteChannelEvaluator extends Recommender.Evaluator {
private static final long MIN_WATCH_PERIOD_MS = 1000 * 60 * 60 * 24; // 1 day
// When there is no watch history, use the current time as a default value.
private long mEarliestWatchStartTimeMs = System.currentTimeMillis();
@Override
protected void onChannelRecordListChanged(List<ChannelRecord> channelRecords) {
for (ChannelRecord cr : channelRecords) {
WatchedProgram[] watchedPrograms = cr.getWatchHistory();
if (watchedPrograms.length > 0
&& mEarliestWatchStartTimeMs > watchedPrograms[0].getWatchStartTimeMs()) {
mEarliestWatchStartTimeMs = watchedPrograms[0].getWatchStartTimeMs();
}
}
}
@Override
public double evaluateChannel(long channelId) {
ChannelRecord cr = getRecommender().getChannelRecord(channelId);
if (cr == null) {
return NOT_RECOMMENDED;
}
if (cr.getTotalWatchDurationMs() == 0) {
return NOT_RECOMMENDED;
}
long watchPeriodMs = System.currentTimeMillis() - mEarliestWatchStartTimeMs;
return (double) cr.getTotalWatchDurationMs() / Math.max(watchPeriodMs, MIN_WATCH_PERIOD_MS);
}
}
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