external/storm-beam/src/main/java/org/apache/storm/beam/translation/runtime/WindowBolt.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.storm.beam.translation.runtime;

import com.google.common.collect.Lists;
import org.apache.storm.task.OutputCollector;
import org.apache.storm.task.TopologyContext;
import org.apache.storm.topology.OutputFieldsDeclarer;
import org.apache.storm.topology.base.BaseWindowedBolt;
import org.apache.storm.tuple.Fields;
import org.apache.storm.tuple.Tuple;
import org.apache.storm.tuple.Values;
import org.apache.storm.windowing.TupleWindow;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.List;
import java.util.Map;

public class WindowBolt extends BaseWindowedBolt {
    private static final Logger LOG = LoggerFactory.getLogger(WindowBolt.class);

    private OutputCollector collector;

    @Override
    public void prepare(Map stormConf, TopologyContext context, OutputCollector collector) {
        super.prepare(stormConf, context, collector);
        this.collector = collector;
    }

    @Override
    public void execute(TupleWindow inputWindow) {
        LOG.info("*******************Executing window with size {}", inputWindow.get().size());
        List values = Lists.newArrayList();
        for(Tuple t :inputWindow.get()){
            values.add(t.getValue(0));
        }
        collector.emit(inputWindow.get(), new Values(values));

    }

    @Override
    public void declareOutputFields(OutputFieldsDeclarer declarer) {
        declarer.declare(new Fields("window"));
    }
}