EvaluatorProcessor.java

package com.yahoo.labs.samoa.evaluation;

/*
 * #%L
 * SAMOA
 * %%
 * Copyright (C) 2013 Yahoo! Inc.
 * %%
 * 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.
 * #L%
 */

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.PrintStream;
import java.util.Collections;
import java.util.List;
import java.util.Vector;
import java.util.concurrent.TimeUnit;

import com.yahoo.labs.samoa.moa.core.Measurement;
import com.yahoo.labs.samoa.moa.evaluation.LearningCurve;
import com.yahoo.labs.samoa.moa.evaluation.LearningEvaluation;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.yahoo.labs.samoa.core.ContentEvent;
import com.yahoo.labs.samoa.core.Processor;
import com.yahoo.labs.samoa.learners.ResultContentEvent;

public class EvaluatorProcessor implements Processor {

	/**
	 * 
	 */
	private static final long serialVersionUID = -2778051819116753612L;

	private static final Logger logger = 
			LoggerFactory.getLogger(EvaluatorProcessor.class);
	
	private static final String ORDERING_MEASUREMENT_NAME = "evaluation instances";
	
	private final PerformanceEvaluator evaluator;
	private final int samplingFrequency;
	private final File dumpFile;
	private transient PrintStream immediateResultStream = null;
	private transient boolean firstDump = true;
	
	
	private long totalCount = 0;
	private long experimentStart = 0;
	
	private long sampleStart = 0;
	
	private LearningCurve learningCurve;
	private int id;

	private EvaluatorProcessor(Builder builder){
		this.evaluator = builder.evaluator;
		this.samplingFrequency = builder.samplingFrequency;
		this.dumpFile = builder.dumpFile;
	}
	
	@Override
	public boolean process(ContentEvent event) {
		
		ResultContentEvent result = (ResultContentEvent) event;
		
		if((totalCount > 0) && (totalCount % samplingFrequency) == 0){
			long sampleEnd = System.nanoTime();
			long sampleDuration = TimeUnit.SECONDS.convert(sampleEnd - sampleStart, TimeUnit.NANOSECONDS);
			sampleStart = sampleEnd;
			
			logger.info("{} seconds for {} instances", sampleDuration, samplingFrequency);
			this.addMeasurement();
		}
		
		if(result.isLastEvent()){
			this.concludeMeasurement();		
			return true;
		}
		
		evaluator.addResult(result.getInstance(), result.getClassVotes());
		totalCount += 1;
		
		if(totalCount == 1){
			sampleStart = System.nanoTime();
			experimentStart = sampleStart;
		}
		
		return false;
	}

	@Override
	public void onCreate(int id) {
		this.id = id;
		this.learningCurve = new LearningCurve(ORDERING_MEASUREMENT_NAME);

		if (this.dumpFile != null) {
			try {
				if(dumpFile.exists()){
					this.immediateResultStream = new PrintStream(
							new FileOutputStream(dumpFile, true), true);
				}else{
					this.immediateResultStream = new PrintStream(
							new FileOutputStream(dumpFile), true);
				}
				
			} catch (FileNotFoundException e) {
				this.immediateResultStream = null;
				logger.error("File not found exception for {}:{}", this.dumpFile.getAbsolutePath(), e.toString());
				
			} catch (Exception e){
				this.immediateResultStream = null;
				logger.error("Exception when creating {}:{}", this.dumpFile.getAbsolutePath(), e.toString());
			}
		}
		
		this.firstDump = true;
	}

	@Override
	public Processor newProcessor(Processor p) {
		EvaluatorProcessor originalProcessor = (EvaluatorProcessor) p;
		EvaluatorProcessor newProcessor = new EvaluatorProcessor.Builder(originalProcessor).build();
		
		if (originalProcessor.learningCurve != null){
			newProcessor.learningCurve = originalProcessor.learningCurve;
		}
		
		return newProcessor;
	}
	
	@Override
	public String toString() {
		StringBuilder report = new StringBuilder();
		
		report.append(EvaluatorProcessor.class.getCanonicalName());
		report.append("id = ").append(this.id);
		report.append('\n');
		
		if(learningCurve.numEntries() > 0){
			report.append(learningCurve.toString());
			report.append('\n');
		}
		return report.toString();
	}
	
	private void addMeasurement(){
		List<Measurement> measurements = new Vector<>();
		measurements.add(new Measurement(ORDERING_MEASUREMENT_NAME, totalCount));

		Collections.addAll(measurements, evaluator.getPerformanceMeasurements());
		
		Measurement[] finalMeasurements = measurements.toArray(new Measurement[measurements.size()]);
		
		LearningEvaluation learningEvaluation = new LearningEvaluation(finalMeasurements);
		learningCurve.insertEntry(learningEvaluation);
		logger.debug("evaluator id = {}", this.id);
		logger.info(learningEvaluation.toString());
		
		if(immediateResultStream != null){
			if(firstDump){
				immediateResultStream.println(learningCurve.headerToString());
				firstDump = false;
			}
			
			immediateResultStream.println(learningCurve.entryToString(learningCurve.numEntries() -1));
			immediateResultStream.flush();
		}
	}
	
	private void concludeMeasurement(){
		logger.info("last event is received!");
		logger.info("total count: {}", this.totalCount);
		
		String learningCurveSummary = this.toString();
		logger.info(learningCurveSummary);

		
		long experimentEnd = System.nanoTime();
		long totalExperimentTime = TimeUnit.SECONDS.convert(experimentEnd - experimentStart, TimeUnit.NANOSECONDS);
		logger.info("total evaluation time: {} seconds for {} instances", totalExperimentTime, totalCount);

		if (immediateResultStream!=null) {
			immediateResultStream.println("# COMPLETED");
			immediateResultStream.flush();
		}
		//logger.info("average throughput rate: {} instances/seconds", (totalCount/totalExperimentTime));
	}
		
	public static class Builder{
		
		private final PerformanceEvaluator evaluator;
		private int samplingFrequency = 100000;
		private File dumpFile = null;
		
		public Builder(PerformanceEvaluator evaluator){
			this.evaluator = evaluator;
		}
		
		public Builder(EvaluatorProcessor oldProcessor){
			this.evaluator = oldProcessor.evaluator;
			this.samplingFrequency = oldProcessor.samplingFrequency;
			this.dumpFile = oldProcessor.dumpFile;
		}
		
		public Builder samplingFrequency(int samplingFrequency){
			this.samplingFrequency = samplingFrequency;
			return this;
		}
		
		public Builder dumpFile(File file){
			this.dumpFile = file;
			return this;
		}
		
		public EvaluatorProcessor build(){
			return new EvaluatorProcessor(this);
		}
	}
}