001 package edu.nrao.sss.model.source.parser;
002
003 import java.io.IOException;
004 import java.io.LineNumberReader;
005 import java.io.Reader;
006 import java.util.Date;
007 import java.text.SimpleDateFormat;
008 import java.text.ParseException;
009
010 import edu.nrao.sss.astronomy.StokesParameter;
011 import edu.nrao.sss.measure.Frequency;
012 import edu.nrao.sss.measure.FrequencyRange;
013 import edu.nrao.sss.measure.FluxDensity;
014 import edu.nrao.sss.measure.TimeInterval;
015 import edu.nrao.sss.model.source.SourceCatalog;
016 import edu.nrao.sss.model.source.Source;
017 import edu.nrao.sss.model.source.Subsource;
018 import edu.nrao.sss.model.source.PointBrightness;
019 import edu.nrao.sss.model.source.BrightnessDistribution;
020 import edu.nrao.sss.model.source.SourceBrightness;
021
022 /**
023 */
024 public class CarmaSourceCatalogReader
025 extends AbstractSourceCatalogReader
026 {
027 private LineNumberReader dataReader;
028 private State parserState;
029 private int[] columnInd;
030 private Source[] sources;
031
032 /** Creates a new instance. */
033 public CarmaSourceCatalogReader()
034 {
035 this.parserState = State.READING_COMMENTS;
036 this.columnInd = null;
037 this.sources = null;
038 }
039
040 /** Prepares this instance to read from a new source. */
041 private void reset(Reader in, SourceCatalog destination)
042 {
043 this.catalog = (destination == null) ? new SourceCatalog() : destination;
044
045 this.readWasSuccessful = false;
046 this.errors.clear();
047
048 this.columnInd = null;
049 this.parserState = State.READING_COMMENTS;
050 this.dataReader = new LineNumberReader(in);
051 }
052
053 private enum State
054 {
055 READING_COMMENTS,
056 READING_SRCS_LINE,
057 READING_EXTERNAL_INFO,
058 READING_INFO,
059 DONE;
060 }
061
062 //============================================================================
063 // INTERFACE SourceCatalogReader
064 //============================================================================
065
066 /**
067 * NOTE: This method closes the incoming Reader!
068 *
069 * @see AbstractSourceCatalogReader#read(java.io.Reader,
070 * edu.nrao.sss.model.source.SourceCatalog)
071 */
072 public boolean read(Reader in, SourceCatalog destination)
073 {
074 reset(in, destination);
075
076 for (String line = getNextLine(); line != null && this.parserState != State.DONE; line = getNextLine())
077 {
078 switch(this.parserState)
079 {
080 case READING_COMMENTS:
081 {
082 // The next line after this one is a line listing all the sources
083 if (line.matches("DATE\\s+FREQ.*"))
084 {
085 this.parserState = State.READING_SRCS_LINE;
086 }
087 break;
088 }
089
090 // This line will tell me exactly where each column starts in the
091 // following lines
092 case READING_SRCS_LINE:
093 {
094 if (line.startsWith("----------------"))
095 {
096 this.parserState = State.READING_EXTERNAL_INFO;
097 }
098
099 else
100 {
101 // If this line doesn't parse, we can't continue
102 if (!processSourcesLine(line))
103 this.parserState = State.DONE;
104 }
105 break;
106 }
107
108 // We currently don't care about this extra info.
109 case READING_EXTERNAL_INFO:
110 {
111 if (line.startsWith("----------------"))
112 {
113 this.parserState = State.READING_INFO;
114 }
115 break;
116 }
117
118 case READING_INFO:
119 {
120 if (line.startsWith("----------------"))
121 {
122 this.parserState = State.DONE;
123 }
124
125 else
126 {
127 // Now we should actually have records to parse.
128 // We do not stop processing more lines if one line fails to parse.
129 processInfo(line);
130 }
131 break;
132 }
133 }
134 }
135
136 try
137 {
138 this.dataReader.close();
139 }
140
141 catch(IOException ioe)
142 {
143 putError(0, "Error closing Reader: " + ioe.getMessage());
144 }
145
146 this.readWasSuccessful = getErrorCount() == 0;
147 return this.readWasSuccessful;
148 }
149
150 //============================================================================
151 //
152 //============================================================================
153
154 /** Reads lines, returning first one that does not cause an error. */
155 private String getNextLine()
156 {
157 int attempt = 0;
158
159 while (++attempt <= 100)
160 {
161 try {
162 return this.dataReader.readLine();
163 }
164 catch (IOException ex) {
165 putError("I/O Exception: " + ex.getMessage());
166 }
167 }
168
169 throw new RuntimeException("Failed " + attempt +
170 " times while attempting to read a line.");
171 }
172
173 /**
174 * @return the <code>n</code><sup>th</sup> field (i.e. column) in the string
175 * according to the column layout found by parsing the table header.
176 */
177 private String getField(int n, String line)
178 {
179 int lineLength = line.length();
180
181 int start = 0;
182 int end = lineLength;
183
184 if (n <= (this.columnInd.length - 2))
185 {
186 start = this.columnInd[n];
187 end = this.columnInd[n + 1];
188 }
189
190 else if (n == (this.columnInd.length - 1))
191 {
192 start = this.columnInd[n];
193 }
194
195 // Make sure that this field exists in this current line before trying a
196 // subtring
197 if (start >= lineLength)
198 return "";
199
200 else if (end > lineLength)
201 return line.substring(start).trim();
202
203 else
204 return line.substring(start, end).trim();
205 }
206
207 private SimpleDateFormat format = new SimpleDateFormat("yyyyMMdd");
208
209 /**
210 * Parses field, discarding any characters after the date itself and returns
211 * a Date object. May return null.
212 */
213 private Date getDate(String field)
214 {
215 try
216 {
217 if (field.length() >= 8)
218 {
219 return format.parse(field.substring(0, 8));
220 }
221
222 else
223 {
224 putError("Invalid date entry found: " + field);
225 }
226 }
227
228 catch (ParseException pe)
229 {
230 putError("Error parsing date string: " + pe.getMessage());
231 }
232
233 return null;
234 }
235
236 /**
237 * @returns a Frequency in GHz with the value specified in field. May return null.
238 */
239 private Frequency getFrequency(String field)
240 {
241 try
242 {
243 field = field.replaceAll("\\*", "");
244 return Frequency.parse(field + " GHz");
245 }
246
247 catch (IllegalArgumentException iae)
248 {
249 putError("Error parsing Frequency: " + iae.getMessage());
250 return null;
251 }
252 }
253
254
255 /**
256 * @returns a Frequency in GHz with the value specified in field. May return null.
257 */
258 private FluxDensity getFluxDensity(String field)
259 {
260 try
261 {
262 // These fields should either be empty or have a <number> <SPACE>
263 // <character(s)>
264 if (field.length() > 0)
265 {
266 field = field.split("\\s+")[0];
267 return FluxDensity.parse(field);
268 }
269 }
270
271 catch (IllegalArgumentException iae)
272 {
273 putError("Error parsing FluxDensity: " + iae.getMessage());
274 }
275
276 return null;
277 }
278
279 /**
280 * Adds <code>fd</code> to the <code>sourceNum</code><sup>th</sup> source
281 */
282 private void addBrightness(int sourceNum, Date date, Frequency freq, FluxDensity fd)
283 {
284 Subsource center = this.sources[sourceNum].getCentralSubsource();
285 PointBrightness pb = (PointBrightness)SourceBrightness.createBrightness(BrightnessDistribution.POINT);
286
287 pb.setPolarization(StokesParameter.I);
288
289 if (date != null)
290 {
291 TimeInterval ti = new TimeInterval();
292 ti.set(date, ti.getEnd());
293 pb.setValidTime(ti);
294 }
295
296 if (freq != null)
297 {
298 pb.setValidFrequency(new FrequencyRange(freq, freq));
299 }
300
301 if (fd != null)
302 {
303 pb.setPeakFluxDensity(fd);
304 }
305
306 center.addBrightness(pb);
307 }
308
309 /**
310 * Processes a line that looks like:
311 * <p><code>yyyymmdd (GHz) 0319+415 0530+135 0854+201 0927+390 1229+020 1256-057 1642+398 1751+096 MWC349 2148+069 2225-049 2251+158
312 * </code>.</p>
313 * This will determine the start index in the following strings of each
314 * column. It also determines the names of the sources we are collecting
315 * information on.
316 * @returns true if successful
317 */
318 private boolean processSourcesLine(String line)
319 {
320 String[] columnHeaders = line.split("\\s+");
321 if (columnHeaders.length < 3)
322 {
323 putError("There are not enough column headers");
324 return false;
325 }
326
327 else
328 {
329 // Now run through the array finding the first index of each
330 // column header. These integers will be the starting indexes of all
331 // of our columns.
332 this.columnInd = new int[columnHeaders.length];
333 this.sources = new Source[columnHeaders.length - 2];
334
335 this.columnInd[0] = line.indexOf(columnHeaders[0]);
336 this.columnInd[1] = line.indexOf(columnHeaders[1]);
337
338 for (int i = 2; i < columnHeaders.length; i++)
339 {
340 this.columnInd[i] = line.indexOf(columnHeaders[i]);
341 this.sources[i - 2] = new Source(columnHeaders[i]);
342 this.sources[i - 2].setOriginOfInformation(this.sourceInfoOrigin);
343 this.catalog.addItem(this.sources[i - 2]);
344 }
345
346 return true;
347 }
348 }
349
350 /**
351 * Each row holds a date, frequency, and flux measurements for each source
352 * named in the header line. Unfortunately, all columns are optional
353 * @returns true if successful
354 */
355 private boolean processInfo(String line)
356 {
357 Date date = getDate(getField(0, line));
358 Frequency freq = getFrequency(getField(1, line));
359
360 for (int n = 2; n < this.columnInd.length; n++)
361 {
362 FluxDensity fd = getFluxDensity(getField(n, line));
363 if (fd != null)
364 {
365 addBrightness(n - 2, date, freq, fd);
366 }
367 }
368
369 return true;
370 }
371
372 /** Adds a new parsing error to our list. */
373 private void putError(String message)
374 {
375 putError(this.dataReader.getLineNumber(), message);
376 }
377 }