com.ikanow.aleph2.analytics.storm.assets.OutputBolt.java Source code

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Here is the source code for com.ikanow.aleph2.analytics.storm.assets.OutputBolt.java

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/*******************************************************************************
 * Copyright 2015, The IKANOW 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.ikanow.aleph2.analytics.storm.assets;

import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Optional;
import java.util.stream.Collectors;
import java.util.stream.StreamSupport;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

import com.fasterxml.jackson.databind.node.ObjectNode;
import com.ikanow.aleph2.data_model.interfaces.data_import.IEnrichmentModuleContext;
import com.ikanow.aleph2.data_model.interfaces.data_import.IEnrichmentStreamingTopology;
import com.ikanow.aleph2.data_model.objects.data_import.DataBucketBean;
import com.ikanow.aleph2.data_model.utils.ContextUtils;

import backtype.storm.task.OutputCollector;
import backtype.storm.task.TopologyContext;
import backtype.storm.topology.OutputFieldsDeclarer;
import backtype.storm.topology.base.BaseRichBolt;
import backtype.storm.tuple.Tuple;

/** Very simple bolt that outputs the objects it receives to the appropriate Aleph2 storage layers
 * @author Alex
 */
public class OutputBolt extends BaseRichBolt {
    private static final long serialVersionUID = -1801739673297414345L;
    private static final Logger _logger = LogManager.getLogger();

    protected final DataBucketBean _bucket;
    protected final String _context_signature;
    protected final String _user_topology_entry_point;

    protected IEnrichmentModuleContext _context;
    protected IEnrichmentStreamingTopology _user_topology;

    protected OutputCollector _collector;

    /** User constructor
     * @param bucket
     * @param context_signature
     * @param user_topology_entry_point
     */
    public OutputBolt(final DataBucketBean bucket, final String context_signature,
            final String user_topology_entry_point) {
        _bucket = bucket;
        _context_signature = context_signature;
        _user_topology_entry_point = user_topology_entry_point;
    }

    @Override
    public void prepare(final @SuppressWarnings("rawtypes") Map arg0, final TopologyContext arg1,
            final OutputCollector arg2) {
        try {
            _context = ContextUtils.getEnrichmentContext(_context_signature);
            _user_topology = (IEnrichmentStreamingTopology) Class.forName(_user_topology_entry_point).newInstance();
            _collector = arg2;
        } catch (Exception e) { // nothing to be done here?
            _logger.error("Failed to get context", e);
        }
    }

    /** Converts from a tuple of a linked hash map
     * @param t
     * @return
     */
    public static LinkedHashMap<String, Object> tupleToLinkedHashMap(final Tuple t) {
        return StreamSupport.stream(t.getFields().spliterator(), false)
                .collect(Collectors.toMap(f -> f, f -> t.getValueByField(f), (m1, m2) -> m1, LinkedHashMap::new));
    }

    /* (non-Javadoc)
     * @see backtype.storm.task.IBolt#execute(backtype.storm.tuple.Tuple)
     */
    @Override
    public void execute(final Tuple arg0) {
        _collector.ack(arg0);
        _context.emitMutableObject(0L,
                (ObjectNode) _user_topology.rebuildObject(arg0, OutputBolt::tupleToLinkedHashMap), Optional.empty(),
                Optional.empty());
    }

    /* (non-Javadoc)
     * @see backtype.storm.topology.IComponent#declareOutputFields(backtype.storm.topology.OutputFieldsDeclarer)
     */
    @Override
    public void declareOutputFields(final OutputFieldsDeclarer arg0) {
        // (nothing to do here)      
    }

}