content: /**
   * Copyright (c) 2019 Siemens AG
   * All rights reserved.
   * 
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions are met:
   * 
   * 1) Redistributions of source code must retain the above copyright notice, this
   *    list of conditions and the following disclaimer.
   * 
   * 2) Redistributions in binary form must reproduce the above copyright notice,
   *    this list of conditions and the following disclaimer in the documentation
   *    and/or other materials provided with the distribution.
   * 
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
   * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
   * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  package at.ac.tuwien.kr.alpha.core.solver;
  
  import org.slf4j.Logger;
  
  /**
   * Collects performance data (mainly number of decisions per second) and outputs them on demand.
   */
  public class PerformanceLog {
  
  	private final ChoiceManager choiceManager;
  	private final TrailAssignment assignment;
  	private final long msBetweenOutputs;
  	
  	private Long timeFirstEntry;
  	private Long timeLastPerformanceLog;
  	private int numberOfChoicesLastPerformanceLog;
  
  	/**
  	 * @param msBetweenOutputs minimum number of milliseconds that have to pass between writing of performance logs.
  	 */
  	public PerformanceLog(ChoiceManager choiceManager, TrailAssignment assignment, long msBetweenOutputs) {
  		super();
  		this.choiceManager = choiceManager;
  		this.assignment = assignment;
  		this.msBetweenOutputs = msBetweenOutputs;
  	}
  
  	public void initialize() {
  		timeFirstEntry = System.currentTimeMillis();
  		timeLastPerformanceLog = timeFirstEntry;
  	}
  
  	/**
  	 * Logs performance statistics to the given logger (at channel INFO).
  	 * @param logger the Logger whose info-channel will be written to.
  	 */
  	public void writeIfTimeForLogging(Logger logger) {
  		long currentTime = System.currentTimeMillis();
  		int currentNumberOfChoices = choiceManager.getChoices();
  		if (currentTime >= timeLastPerformanceLog + msBetweenOutputs) {
  			logger.info("Decisions in {}s: {}", (currentTime - timeLastPerformanceLog) / 1000.0f, currentNumberOfChoices - numberOfChoicesLastPerformanceLog);
  			timeLastPerformanceLog = currentTime;
  			numberOfChoicesLastPerformanceLog = currentNumberOfChoices;
  			float overallTime = (currentTime - timeFirstEntry) / 1000.0f;
  			float decisionsPerSec = currentNumberOfChoices / overallTime;
  			logger.info("Overall performance: {} decisions in {}s or {} decisions per sec. Overall replayed assignments: {}.", currentNumberOfChoices, overallTime, decisionsPerSec, assignment.replayCounter);
  		}
  	}
  }