001 package edu.nrao.sss.astronomy;
002
003 import java.util.Date;
004
005 import javax.xml.bind.annotation.XmlElement;
006 import javax.xml.bind.annotation.XmlRootElement;
007
008 import edu.nrao.sss.measure.Distance;
009 import edu.nrao.sss.measure.Latitude;
010 import edu.nrao.sss.measure.Longitude;
011
012 /**
013 * A very basic implementation of a {@link SkyPosition sky position}.
014 * <p>
015 * <b>Version Info:</b>
016 * <table style="margin-left:2em">
017 * <tr><td>$Revision: 1156 $</td></tr>
018 * <tr><td>$Date: 2008-03-12 11:43:13 -0600 (Wed, 12 Mar 2008) $</td></tr>
019 * <tr><td>$Author: dharland $</td></tr>
020 * </table></p>
021 *
022 * @author David M. Harland
023 * @since 2007-04-17
024 */
025 @XmlRootElement
026 public class SimpleSkyPosition
027 extends AbsSkyPos
028 {
029 private Longitude longitude;
030 private Latitude latitude;
031 private Distance distance;
032
033 private Longitude longitudeUncertainty;
034 private Latitude latitudeUncertainty;
035 private Distance distanceUncertainty;
036
037 /** Creates a new equatorial, J2000, position. */
038 public SimpleSkyPosition()
039 {
040 this(CelestialCoordinateSystem.EQUATORIAL, Epoch.J2000);
041 }
042
043 /** Creates a new instance with the given properties. */
044 public SimpleSkyPosition(CelestialCoordinateSystem system, Epoch epoch)
045 {
046 super(system, epoch);
047
048 longitude = new Longitude();
049 latitude = new Latitude();
050 distance = new Distance();
051
052 longitudeUncertainty = new Longitude();
053 latitudeUncertainty = new Latitude();
054 distanceUncertainty = new Distance();
055 }
056
057 @Override
058 public void reset()
059 {
060 super.reset();
061
062 longitude.reset();
063 latitude.reset();
064 distance.reset();
065
066 longitudeUncertainty.reset();
067 latitudeUncertainty.reset();
068 distanceUncertainty.reset();
069 }
070
071 //============================================================================
072 //
073 //============================================================================
074
075 /* (non-Javadoc)
076 * @see SkyPosition#getType()
077 */
078 public SkyPositionType getType() { return SkyPositionType.SIMPLE; }
079
080 /* (non-Javadoc)
081 * @see edu.nrao.sss.astronomy.SkyPosition#isMoving()
082 */
083 public boolean isMoving() { return false; }
084
085 //============================================================================
086 //
087 //============================================================================
088
089 /**
090 * Sets the longitude of this position.
091 * <p>
092 * If {@code newLongitude} is <i>null</i>, this method creates, and saves a
093 * reference to, a new longitude object. Otherwise it saves a reference
094 * to {@code newLongitude}. This means that any changes made to
095 * (a non-null) {@code newLongitude} by clients after this call
096 * <i>will</i> be reflected in this position.</p>
097 *
098 * @param newLongitude a new longitude for this position.
099 */
100 public void setLongitude(Longitude newLongitude)
101 {
102 longitude = (newLongitude == null) ? new Longitude() : newLongitude;
103 }
104
105 /**
106 * Returns the current longitude of this position.
107 * <p>
108 * The returned object is guaranteed to be non-null and is also a reference
109 * to the internal longitude held by this position. This means any changes
110 * made by clients to the returned object will be reflected in this
111 * position.</p>
112 *
113 * @return the current longitude of this position.
114 */
115 @XmlElement
116 @Override
117 public Longitude getLongitude()
118 {
119 return longitude;
120 }
121
122 /**
123 * Sets the latitude of this position.
124 * <p>
125 * If {@code newLatitude} is <i>null</i>, this method creates, and saves a
126 * reference to, a new latitude object. Otherwise it saves a reference
127 * to {@code newLatitude}. This means that any changes made to
128 * (a non-null) {@code newLatitude} by clients after this call
129 * <i>will</i> be reflected in this position.</p>
130 *
131 * @param newLatitude a new latitude for this position.
132 */
133 public void setLatitude(Latitude newLatitude)
134 {
135 latitude = (newLatitude == null) ? new Latitude() : newLatitude;
136 }
137
138 /**
139 * Returns the current latitude of this position.
140 * <p>
141 * The returned object is guaranteed to be non-null and is also a reference
142 * to the internal latitude held by this position. This means any changes
143 * made by clients to the returned object will be reflected in this
144 * position.</p>
145 *
146 * @return the current latitude of this position.
147 */
148 @XmlElement
149 @Override
150 public Latitude getLatitude()
151 {
152 return latitude;
153 }
154
155 /**
156 * Sets the distance of this position.
157 * <p>
158 * If {@code newDistance} is <i>null</i>, this method creates, and saves a
159 * reference to, a new distance object. Otherwise it saves a reference
160 * to {@code newDistance}. This means that any changes made to
161 * (a non-null) {@code newDistance} by clients after this call
162 * <i>will</i> be reflected in this position.</p>
163 *
164 * @param newDistance a new distance for this position.
165 */
166 public void setDistance(Distance newDistance)
167 {
168 distance = (newDistance == null) ? new Distance() : newDistance;
169 }
170
171 /**
172 * Returns the current distance of this position.
173 * <p>
174 * The returned object is guaranteed to be non-null and is also a reference
175 * to the internal distance held by this position. This means any changes
176 * made by clients to the returned object will be reflected in this
177 * position.</p>
178 *
179 * @return the current distance of this position.
180 */
181 @XmlElement
182 @Override
183 public Distance getDistance()
184 {
185 return distance;
186 }
187
188 //----------------------------------------------------------------------------
189 // Position at point in time
190 //----------------------------------------------------------------------------
191
192 /**
193 * Returns the longitude of this position at the given point in time.
194 * <p>
195 * The returned object is guaranteed to be non-null and is also a reference
196 * to the internal longitude held by this position. This means any changes
197 * made by clients to the returned object will be reflected in this
198 * position.</p>
199 * <p>
200 * Since this class has no concept of time, the value returned here will
201 * be the same as that returned by the corresponding no-argument method.</p>
202 *
203 * @return the longitude of this position at the given point in time.
204 */
205 public Longitude getLongitude(Date time)
206 {
207 return longitude;
208 }
209
210 /**
211 * Returns the latitude of this position at the given point in time.
212 * <p>
213 * The returned object is guaranteed to be non-null and is also a reference
214 * to the internal latitude held by this position. This means any changes
215 * made by clients to the returned object will be reflected in this
216 * position.</p>
217 * <p>
218 * Since this class has no concept of time, the value returned here will
219 * be the same as that returned by the corresponding no-argument method.</p>
220 *
221 * @return the latitude of this position at the given point in time.
222 */
223 public Latitude getLatitude(Date time)
224 {
225 return latitude;
226 }
227
228 /**
229 * Returns the distance of this position at the given point in time.
230 * <p>
231 * The returned object is guaranteed to be non-null and is also a reference
232 * to the internal distance held by this position. This means any changes
233 * made by clients to the returned object will be reflected in this
234 * position.</p>
235 * <p>
236 * Since this class has no concept of time, the value returned here will
237 * be the same as that returned by the corresponding no-argument method.</p>
238 *
239 * @return the distance at the given point in time.
240 */
241 public Distance getDistance(Date time)
242 {
243 return distance;
244 }
245
246 //----------------------------------------------------------------------------
247 // Uncertainties
248 //----------------------------------------------------------------------------
249
250 /**
251 * Sets the uncertainty in the longitude of this position.
252 * <p>
253 * If {@code newUncertainty} is <i>null</i>, this method creates, and saves a
254 * reference to, a new longitude object. Otherwise it saves a reference
255 * to {@code newUncertainty}. This means that any changes made to
256 * (a non-null) {@code newUncertainty} by clients after this call
257 * <i>will</i> be reflected in this position.</p>
258 *
259 * @param newUncertainty a new value for the uncertainty of the longitude of
260 * this position.
261 */
262 public void setLongitudeUncertainty(Longitude newUncertainty)
263 {
264 longitudeUncertainty =
265 (newUncertainty == null) ? new Longitude() : newUncertainty;
266 }
267
268 /**
269 * Returns the uncertainty in the longitude of this position.
270 * <p>
271 * The returned object is guaranteed to be non-null and is also a reference
272 * to the internal uncertainty held by this position. This means any changes
273 * made by clients to the returned object will be reflected in this
274 * position.</p>
275 *
276 * @return the uncertainty in the longitude of this position.
277 */
278 @XmlElement
279 @Override
280 public Longitude getLongitudeUncertainty()
281 {
282 return longitudeUncertainty;
283 }
284
285 /**
286 * Sets the uncertainty in the latitude of this position.
287 * <p>
288 * If {@code newUncertainty} is <i>null</i>, this method creates, and saves a
289 * reference to, a new latitude object. Otherwise it saves a reference
290 * to {@code newUncertainty}. This means that any changes made to
291 * (a non-null) {@code newUncertainty} by clients after this call
292 * <i>will</i> be reflected in this position.</p>
293 *
294 * @param newUncertainty a new value for the uncertainty of the latitude of
295 * this position.
296 */
297 public void setLatitudeUncertainty(Latitude newUncertainty)
298 {
299 latitudeUncertainty =
300 (newUncertainty == null) ? new Latitude() : newUncertainty;
301 }
302
303 /**
304 * Returns the uncertainty in the latitude of this position.
305 * <p>
306 * The returned object is guaranteed to be non-null and is also a reference
307 * to the internal uncertainty held by this position. This means any changes
308 * made by clients to the returned object will be reflected in this
309 * position.</p>
310 *
311 * @return the uncertainty in the latitude of this position.
312 */
313 @XmlElement
314 @Override
315 public Latitude getLatitudeUncertainty()
316 {
317 return latitudeUncertainty;
318 }
319
320 /**
321 * Sets the uncertainty in the distance of this position.
322 * <p>
323 * If {@code newUncertainty} is <i>null</i>, this method creates, and saves a
324 * reference to, a new distance object. Otherwise it saves a reference
325 * to {@code newUncertainty}. This means that any changes made to
326 * (a non-null) {@code newUncertainty} by clients after this call
327 * <i>will</i> be reflected in this position.</p>
328 *
329 * @param newUncertainty a new value for the uncertainty of the distance of
330 * this position.
331 */
332 public void setDistanceUncertainty(Distance newUncertainty)
333 {
334 distanceUncertainty =
335 (newUncertainty == null) ? new Distance() : newUncertainty;
336 }
337
338 /**
339 * Returns the uncertainty in the distance of this position.
340 * <p>
341 * The returned object is guaranteed to be non-null and is also a reference
342 * to the internal uncertainty held by this position. This means any changes
343 * made by clients to the returned object will be reflected in this
344 * position.</p>
345 *
346 * @return the uncertainty in the distance of this position.
347 */
348 @XmlElement
349 @Override
350 public Distance getDistanceUncertainty()
351 {
352 return distanceUncertainty;
353 }
354
355 //============================================================================
356 //
357 //============================================================================
358
359 /**
360 * Creates and returns a new polynomial position whose time-zero values are
361 * the same as those of this position.
362 * The returned position has a default reference time and a default
363 * valid time interval.
364 *
365 * @return a new polynomial position based on this position.
366 */
367 public PolynomialPosition toPolynomialPosition()
368 {
369 PolynomialPosition pp = new PolynomialPosition();
370
371 pp.setCoordinateSystem(getCoordinateSystem());
372 pp.setEpoch(getEpoch());
373
374 pp.setDistanceAtTimeZero(getDistance());
375 pp.setLongitudeAtTimeZero(getLongitude());
376 pp.setLatitudeAtTimeZero(getLatitude());
377
378 pp.setDistanceUncertainty(getDistanceUncertainty());
379 pp.setLongitudeUncertainty(getLongitudeUncertainty());
380 pp.setLatitudeUncertainty(getLatitudeUncertainty());
381
382 return pp;
383 }
384
385 //============================================================================
386 //
387 //============================================================================
388
389 @Override
390 public String toString()
391 {
392 StringBuilder buff = appendTo(null).append(',');
393
394 buff.append(longitude).append("+/-").append(longitudeUncertainty);
395 buff.append(',');
396 buff.append(latitude).append("+/-").append(latitudeUncertainty);
397 buff.append(',');
398 buff.append(distance).append("+/-").append(distanceUncertainty);
399
400 return buff.toString();
401 }
402
403 /**
404 * Returns a copy of this sky position.
405 * <p>
406 * If anything goes wrong during the cloning procedure,
407 * a {@code RuntimeException} will be thrown.</p>
408 */
409 @Override
410 public SimpleSkyPosition clone()
411 {
412 SimpleSkyPosition clone = null;
413
414 try
415 {
416 //This line takes care of the primitive & immutable fields properly
417 clone = (SimpleSkyPosition)super.clone();
418
419 clone.longitude = this.longitude.clone();
420 clone.latitude = this.latitude.clone();
421 clone.distance = this.distance.clone();
422
423 clone.longitudeUncertainty = this.longitudeUncertainty.clone();
424 clone.latitudeUncertainty = this.latitudeUncertainty.clone();
425 clone.distanceUncertainty = this.distanceUncertainty.clone();
426 }
427 catch (Exception ex)
428 {
429 throw new RuntimeException(ex);
430 }
431
432 return clone;
433 }
434
435 /** Creates and returns a copy of the given sky position. */
436 static SimpleSkyPosition copy(SkyPosition original, Date time)
437 {
438 SimpleSkyPosition copy = new SimpleSkyPosition();
439
440 copy.setCoordinateSystem(original.getCoordinateSystem());
441 copy.setEpoch(original.getEpoch());
442
443 copy.setLatitude (original.getLatitude(time).clone());
444 copy.setLongitude(original.getLongitude(time).clone());
445 copy.setDistance (original.getDistance(time).clone());
446
447 copy.setLatitudeUncertainty (original.getLatitudeUncertainty().clone());
448 copy.setLongitudeUncertainty(original.getLongitudeUncertainty().clone());
449 copy.setDistanceUncertainty (original.getDistanceUncertainty().clone());
450
451 return copy;
452 }
453
454 /** Returns <i>true</i> if {@code o} is equal to this position. */
455 @Override
456 public boolean equals(Object o)
457 {
458 //Quick exit if o is this
459 if (o == this)
460 return true;
461
462 //Quick exit if super class determines not equal
463 if (!super.equals(o))
464 return false;
465
466 //Super class determined o is non-null & of same class
467 SimpleSkyPosition other = (SimpleSkyPosition)o;
468
469 //NOTE: Absence of origin of information here is intentional.
470
471 return other.longitude.equals(this.longitude) &&
472 other.latitude.equals (this.latitude ) &&
473 other.distance.equals (this.distance ) &&
474
475 other.longitudeUncertainty.equals(this.longitudeUncertainty) &&
476 other.latitudeUncertainty.equals (this.latitudeUncertainty ) &&
477 other.distanceUncertainty.equals (this.distanceUncertainty );
478 }
479
480 /** Returns a hash code value for this position. */
481 @Override
482 public int hashCode()
483 {
484 //Taken from the Effective Java book by Joshua Bloch.
485 //The constants 17 & 37 are arbitrary & carry no meaning.
486
487 //You MUST keep this method in synch with equals()
488
489 int result = super.hashCode();
490
491 result = 37 * result + longitude.hashCode();
492 result = 37 * result + latitude.hashCode();
493 result = 37 * result + distance.hashCode();
494
495 result = 37 * result + longitudeUncertainty.hashCode();
496 result = 37 * result + latitudeUncertainty.hashCode();
497 result = 37 * result + distanceUncertainty.hashCode();
498
499 return result;
500 }
501 }