DegreeCentralityBolt.java

/*
 * Copyright © 2012-2013 The University of Texas at Dallas
 *
 * 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 edu.utdallas.cs.stormrider.topology.impl.analyze;

import java.util.Iterator;
import java.util.Map;

import edu.utdallas.cs.stormrider.topology.TopologyException;
import edu.utdallas.cs.stormrider.util.StormRiderViewConstants;
import edu.utdallas.cs.stormrider.views.Views;
import edu.utdallas.cs.stormrider.views.ViewsFactory;

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

public class DegreeCentralityBolt implements IRichBolt 
{
	private static final long serialVersionUID = 1L ;

	Views views = null ;
	
	long totalNodes = 0L ;
	
	public DegreeCentralityBolt( String configFile ) 
	{ 
		views = ViewsFactory.getViews( configFile ) ;
		this.totalNodes = views.getTotalNodes() ; 
	}
	
	@SuppressWarnings("rawtypes")
	@Override
    public void prepare( Map conf, TopologyContext context, OutputCollector collector) { }

    @Override
    public void execute( Tuple input ) 
    {
    	try
    	{
    		String node = input.getString( 0 ) ;
    		long degree = 0L ;
    		Iterator<byte[]> iterAdjList = views.getAdjList( node ) ;
    		while( iterAdjList.hasNext() )
    		{
    			degree++ ; iterAdjList.next() ;
    		}
    		double degC = ( degree * 1.0 ) / totalNodes ;
    		views.updateMetricValue( node, StormRiderViewConstants.colMetricDegC, degC ) ;
    	}
        catch( Exception e ) { throw new TopologyException( "Exception in degree centrality bolt:: ", e ) ; }
    }

    @Override
    public void cleanup() { }

    @Override
    public void declareOutputFields( OutputFieldsDeclarer declarer ) { }    
    
	@Override
	public Map<String, Object> getComponentConfiguration() { return null ; }
}