code: /*******************************************************************************
   * Copyright (c) 2013 Attila Kovacs <attila[AT]sigmyne.com>.
   * All rights reserved. 
   * 
   * This file is part of crush.
   * 
   *     crush is free software: you can redistribute it and/or modify
   *     it under the terms of the GNU General Public License as published by
   *     the Free Software Foundation, either version 3 of the License, or
   *     (at your option) any later version.
   * 
   *     crush is distributed in the hope that it will be useful,
   *     but WITHOUT ANY WARRANTY; without even the implied warranty of
   *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   *     GNU General Public License for more details.
   * 
   *     You should have received a copy of the GNU General Public License
   *     along with crush.  If not, see <http://www.gnu.org/licenses/>.
   * 
   * Contributors:
   *     Attila Kovacs <attila[AT]sigmyne.com> - initial API and implementation
   ******************************************************************************/
  package crush.telescope.apex;
  
  import java.io.*;
  import java.util.*;
  
  import crush.CRUSH;
  import jnum.Unit;
  import jnum.Util;
  import jnum.data.DataPoint;
  import jnum.data.ScalarLocality;
  import jnum.io.LineParser;
  import jnum.text.SmartTokenizer;
  import jnum.data.LocalAverage;
  import jnum.data.Locality;
  import jnum.data.LocalizedData;
  
  
  
  public class APEXTauTable extends LocalAverage<APEXTauTable.Entry> {
  	/**
  	 * 
  	 */
  	private static final long serialVersionUID = -7962217110619389946L;
  	
  	private static Hashtable<String, APEXTauTable> tables = new Hashtable<>();
  
  	public String fileName;
  	public double timeWindow = 1.5 * Unit.hour;
  	
  
  	
  	private APEXTauTable(String fileName) throws IOException {
  		read(fileName);
  	}
  	
  	protected void read(String fileName) throws IOException {
  		new LineParser() {
              @Override
              protected boolean parse(String line) throws Exception {
                  SmartTokenizer tokens = new SmartTokenizer(line);
                  Entry skydip = new Entry();
                  tokens.skip(2);
                  skydip.timeStamp = new TimeStamp(tokens.nextDouble());
                  skydip.tau.setValue(tokens.nextDouble());
                  skydip.tau.setRMS(1.0);
                  add(skydip);
                  return true;
              }   
  		}.read(fileName);
  		
  		this.fileName = fileName;
  		
  		CRUSH.info(this, "[Loading tau data] -- " + size() + " values parsed.");
  	}	
  	
  	public double getTau(double MJD) {
  		Entry mean = getLocalAverage(new TimeStamp(MJD));
  		
  		if(mean.tau.weight() == 0.0) {
  			CRUSH.info(this, "... No skydip data was found in specified time window.");
  			
  			if(timeWindow < 6.0 * Unit.hour) {
  				CRUSH.info(this, "... expanding tau lookup window to 6 hours.");
  				timeWindow = 6.0 * Unit.hour;
  				mean = getLocalAverage(new TimeStamp(MJD));
  			}
  			else {
  				CRUSH.warning(this, "Local tau is unknown.");
  				return 0.0;
  			}
  		}
  		else if(Double.isInfinite(mean.tau.value())) {
  			CRUSH.warning(this, "Inifinite local tau.");
  			return 0.0;
  		}
  		
  		CRUSH.values(this, "Local average tau = " + Util.f3.format(mean.tau.value()) + " (from " + mean.measurements + " skydips)");
  		return mean.tau.value();
  	}
  	
  	class TimeStamp extends ScalarLocality {
  		
  		public TimeStamp(double MJD) { super(MJD); }
  		
  		@Override
  		public double distanceTo(Locality other) {
  			return super.distanceTo(other) * Unit.day / Math.abs(timeWindow);
  		}
  	}
  
  	
  	class Entry extends LocalizedData {
  		/**
  		 * 
  		 */
  		private static final long serialVersionUID = 3293214668641028650L;
  		TimeStamp timeStamp;
  		DataPoint tau = new DataPoint();
  		
  		
  		@Override
  		public Locality getLocality() {
  			return timeStamp;
  		}
  
  		@Override
  		public void setLocality(Locality loc) {
  			timeStamp = (TimeStamp) loc;
  		}
  
  		@Override
  		protected void averageWidth(LocalizedData other, Object env, double relativeWeight) {
  			Entry entry = (Entry) other;
  			tau.average(entry.tau.value(), relativeWeight * entry.tau.weight());
  		}	
  	}
  
  	@Override
  	public Entry getLocalizedDataInstance() {
  		return new Entry();
  	}
  	
  	public static APEXTauTable get(String fileName) throws IOException {
  	    APEXTauTable table = tables.get(fileName);
  	    if(table == null) {
  	        table = new APEXTauTable(fileName);
  	        tables.put(fileName, table);
  	    }
  	    return table;
  	}
  
  }
  
  