nl.esi.metis.aisparser.impl.AISMessage23Impl Maven / Gradle / Ivy

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This package supports the parsing of AIS messages in Java. AIS, the Automatic Identification System, is a system aiming at improving maritime safety by exchanging messages between ships, other vehicles in particular aircraft involved in search-and-rescue (SAR), and (fixed) base stations. To be precise, this package support the ITU-R M.1371-4 AIS standard. See our extensive javadoc and in particular the class AISParser for more information on how to use this package. The parser was used in the Poseidon project, and is improved in the Metis project to better handle uncertain information. Both projects were led by the Embedded Systems Institute. In both projects Thales Nederlands was the carrying industrial partner, and multiple Dutch universities participated.

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package nl.esi.metis.aisparser.impl;

import nl.esi.metis.aisparser.AISMessage23;
import nl.esi.metis.aisparser.DestinationArea;
import nl.esi.metis.aisparser.Sixbit;
import nl.esi.metis.aisparser.UtilsPositionInfo;
import nl.esi.metis.aisparser.UtilsSpare;
import nl.esi.metis.aisparser.annotations.AISIllegalValueAnnotation;
import nl.esi.metis.aisparser.provenance.VDMMessageProvenance;

/** ESI AIS Parser
 * 
* Copyright 2011/2012 by Pierre van de Laar (Embedded Systems Institute)
 * Copyright 2008 by Brian C. Lane 
 * All Rights Reserved
 * 
 * @author Pierre van de Laar
 * @author Brian C. Lane
 */


/** AIS Message 23
 * Group Assignment Command
 * 
 * Field Nr     Field Name                          NrOf Bits   (from, to )
 * ------------------------------------------------------------------------
 *  1	messageID                               	   6	(   1,   6)
 *  2	repeatIndicator                         	   2	(   7,   8)
 *  3	userID                                  	  30	(   9,  38)
 *  4	spare1                                  	   2	(  39,  40)
 *  5	destinationArea                         	  70	(  41, 110)
 *  6	stationType                             	   4	( 111, 114)
 *  7	typeOfShipAndCargoType                  	   8	( 115, 122)
 *  8	spare2                                  	  22	( 123, 144)
 *  9	txrxMode                                	   2	( 145, 146)
 * 10	reportingInterval                       	   4	( 147, 150)
 * 11	quietTime                               	   4	( 151, 154)
 * 12	spare3                                  	   6	( 155, 160)
 *                                                      ---- +
 *                           (maximum) number of bits    160
 */
class AISMessage23Impl extends AISMessageImpl implements AISMessage23 {
	public static final int LENGTH = 160;

	public static boolean validLength(int length)
	{
		return (length == LENGTH);
	}
	
	/**
	 * Return the difference in available and needed bits to parse this sixbit as an AisMessagePositionReport
	 * A positive difference indicates that there are more bits available than needed by the standard.
	 * @param sb
	 * @return
	 */
	public static int differenceInBits(Sixbit sb)
	{
		return (sb.available() - LENGTH);
	}
	
	private static final int SPARE1_FROM = 39;
	private static final int SPARE1_TO = 40;

	private int spare1;
	/** spare1
	 * @return int value of spare1 (2 bits [39,40])
	 */
	public int getSpare1() { return spare1; }


	private static final int DESTINATIONAREA_FROM = 41;
	//private static final int DESTINATIONAREA_TO = 110;

	private DestinationArea destinationArea;
	/** destinationArea
	 * @return DestinationArea value of destinationArea (70 bits [41,110])
	 */
	public DestinationArea getDestinationArea() { return destinationArea; }


	private static final int STATIONTYPE_FROM = 111;
	private static final int STATIONTYPE_TO = 114;

	private int stationType;
	/** stationType
	 * @return int value of stationType (4 bits [111,114])
	 */
	public int getStationType() { return stationType; }


	private static final int TYPEOFSHIPANDCARGOTYPE_FROM = 115;
	private static final int TYPEOFSHIPANDCARGOTYPE_TO = 122;

	private int typeOfShipAndCargoType;
	/** typeOfShipAndCargoType
	 * @return int value of typeOfShipAndCargoType (8 bits [115,122])
	 */
	public int getTypeOfShipAndCargoType() { return typeOfShipAndCargoType; }


	private static final int SPARE2_FROM = 123;
	private static final int SPARE2_TO = 144;

	private int spare2;
	/** spare2
	 * @return int value of spare2 (22 bits [123,144])
	 */
	public int getSpare2() { return spare2; }


	private static final int TXRXMODE_FROM = 145;
	private static final int TXRXMODE_TO = 146;

	private int txrxMode;
	/** txrxMode
	 * @return int value of txrxMode (2 bits [145,146])
	 */
	public int getTxrxMode() { return txrxMode; }


	private static final int REPORTINGINTERVAL_FROM = 147;
	private static final int REPORTINGINTERVAL_TO = 150;

	private int reportingInterval;
	/** reportingInterval
	 * @return int value of reportingInterval (4 bits [147,150])
	 */
	public int getReportingInterval() { return reportingInterval; }


	private static final int QUIETTIME_FROM = 151;
	private static final int QUIETTIME_TO = 154;

	private int quietTime;
	/** quietTime
	 * @return int value of quietTime (4 bits [151,154])
	 */
	public int getQuietTime() { return quietTime; }


	private static final int SPARE3_FROM = 155;
	private static final int SPARE3_TO = 160;

	private int spare3;
	/** spare3
	 * @return int value of spare3 (6 bits [155,160])
	 */
	public int getSpare3() { return spare3; }


	/** AISMessage 23 constructor
	 * @param content AIS content
	 * @param prov the provenance of the message
	 * @precondition validLength(content.length()) && AISMessageBase.getMessageId(content)==23
	 */
	public AISMessage23Impl(Sixbit content, VDMMessageProvenance prov)
	{
		super(content, prov);
		assert(validLength(content.length()));
		assert(getMessageID() == 23);

		spare1 = content.getIntFromTo(SPARE1_FROM,SPARE1_TO);
	    if (!UtilsSpare.isSpareSemanticallyCorrect(spare1))
	    {
	    	annotations.add(new AISIllegalValueAnnotation("getSpare1", spare1, UtilsSpare.range));
	    }
		destinationArea = new DestinationArea( DESTINATIONAREA_FROM, content);
		if (!UtilsPositionInfo.isLongitudeSemanticallyCorrect(destinationArea.longitudeUpperRightCornerInDegrees()))
	    {
	    	annotations.add (new AISIllegalValueAnnotation("getDestinationArea.longitudeUpperRightCorner",destinationArea.longitudeUpperRightCornerInDegrees(), UtilsPositionInfo.rangeLongitude));
	    }
		if (!UtilsPositionInfo.isLongitudeSemanticallyCorrect(destinationArea.longitudeLowerLeftCornerInDegrees()))
	    {
	    	annotations.add (new AISIllegalValueAnnotation("getDestinationArea.longitudeLowerLeftCorner",destinationArea.longitudeLowerLeftCornerInDegrees(), UtilsPositionInfo.rangeLongitude));
	    }
    	if (!UtilsPositionInfo.isLatitudeSemanticallyCorrect(destinationArea.latitudeUpperRightCornerInDegrees()))
	    {
	    	annotations.add (new AISIllegalValueAnnotation("getDestinationArea.latitudeUpperRightCorner",destinationArea.latitudeUpperRightCornerInDegrees(), UtilsPositionInfo.rangeLatitude));
	    }
    	if (!UtilsPositionInfo.isLatitudeSemanticallyCorrect(destinationArea.latitudeLowerLeftCornerInDegrees()))
	    {
	    	annotations.add (new AISIllegalValueAnnotation("getDestinationArea.latitudeLowerLeftCorner",destinationArea.latitudeLowerLeftCornerInDegrees(), UtilsPositionInfo.rangeLatitude));
	    }
		stationType = content.getIntFromTo(STATIONTYPE_FROM,STATIONTYPE_TO);
		typeOfShipAndCargoType = content.getIntFromTo(TYPEOFSHIPANDCARGOTYPE_FROM,TYPEOFSHIPANDCARGOTYPE_TO);
		spare2 = content.getIntFromTo(SPARE2_FROM,SPARE2_TO);
	    if (!UtilsSpare.isSpareSemanticallyCorrect(spare2))
	    {
	    	annotations.add(new AISIllegalValueAnnotation("getSpare2", spare2, UtilsSpare.range));
	    }
		txrxMode = content.getIntFromTo(TXRXMODE_FROM,TXRXMODE_TO);
		reportingInterval = content.getIntFromTo(REPORTINGINTERVAL_FROM,REPORTINGINTERVAL_TO);
		quietTime = content.getIntFromTo(QUIETTIME_FROM,QUIETTIME_TO);
		spare3 = content.getIntFromTo(SPARE3_FROM,SPARE3_TO);
	    if (!UtilsSpare.isSpareSemanticallyCorrect(spare3))
	    {
	    	annotations.add(new AISIllegalValueAnnotation("getSpare3", spare3, UtilsSpare.range));
	    }
	}
}