001 /* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 018 package org.apache.commons.math3.complex; 019 020 import java.text.FieldPosition; 021 import java.text.NumberFormat; 022 import java.text.ParsePosition; 023 import java.util.Locale; 024 025 import org.apache.commons.math3.exception.MathIllegalArgumentException; 026 import org.apache.commons.math3.exception.MathParseException; 027 import org.apache.commons.math3.exception.NoDataException; 028 import org.apache.commons.math3.exception.NullArgumentException; 029 import org.apache.commons.math3.exception.util.LocalizedFormats; 030 import org.apache.commons.math3.util.CompositeFormat; 031 032 /** 033 * Formats a Complex number in cartesian format "Re(c) + Im(c)i". 'i' can 034 * be replaced with 'j' (or anything else), and the number format for both real 035 * and imaginary parts can be configured. 036 * 037 * @version $Id: ComplexFormat.java 1416643 2012-12-03 19:37:14Z tn $ 038 */ 039 public class ComplexFormat { 040 041 /** The default imaginary character. */ 042 private static final String DEFAULT_IMAGINARY_CHARACTER = "i"; 043 /** The notation used to signify the imaginary part of the complex number. */ 044 private final String imaginaryCharacter; 045 /** The format used for the imaginary part. */ 046 private final NumberFormat imaginaryFormat; 047 /** The format used for the real part. */ 048 private final NumberFormat realFormat; 049 050 /** 051 * Create an instance with the default imaginary character, 'i', and the 052 * default number format for both real and imaginary parts. 053 */ 054 public ComplexFormat() { 055 this.imaginaryCharacter = DEFAULT_IMAGINARY_CHARACTER; 056 this.imaginaryFormat = CompositeFormat.getDefaultNumberFormat(); 057 this.realFormat = imaginaryFormat; 058 } 059 060 /** 061 * Create an instance with a custom number format for both real and 062 * imaginary parts. 063 * @param format the custom format for both real and imaginary parts. 064 * @throws NullArgumentException if {@code realFormat} is {@code null}. 065 */ 066 public ComplexFormat(NumberFormat format) throws NullArgumentException { 067 if (format == null) { 068 throw new NullArgumentException(LocalizedFormats.IMAGINARY_FORMAT); 069 } 070 this.imaginaryCharacter = DEFAULT_IMAGINARY_CHARACTER; 071 this.imaginaryFormat = format; 072 this.realFormat = format; 073 } 074 075 /** 076 * Create an instance with a custom number format for the real part and a 077 * custom number format for the imaginary part. 078 * @param realFormat the custom format for the real part. 079 * @param imaginaryFormat the custom format for the imaginary part. 080 * @throws NullArgumentException if {@code imaginaryFormat} is {@code null}. 081 * @throws NullArgumentException if {@code realFormat} is {@code null}. 082 */ 083 public ComplexFormat(NumberFormat realFormat, NumberFormat imaginaryFormat) 084 throws NullArgumentException { 085 if (imaginaryFormat == null) { 086 throw new NullArgumentException(LocalizedFormats.IMAGINARY_FORMAT); 087 } 088 if (realFormat == null) { 089 throw new NullArgumentException(LocalizedFormats.REAL_FORMAT); 090 } 091 092 this.imaginaryCharacter = DEFAULT_IMAGINARY_CHARACTER; 093 this.imaginaryFormat = imaginaryFormat; 094 this.realFormat = realFormat; 095 } 096 097 /** 098 * Create an instance with a custom imaginary character, and the default 099 * number format for both real and imaginary parts. 100 * @param imaginaryCharacter The custom imaginary character. 101 * @throws NullArgumentException if {@code imaginaryCharacter} is 102 * {@code null}. 103 * @throws NoDataException if {@code imaginaryCharacter} is an 104 * empty string. 105 */ 106 public ComplexFormat(String imaginaryCharacter) 107 throws NullArgumentException, NoDataException { 108 this(imaginaryCharacter, CompositeFormat.getDefaultNumberFormat()); 109 } 110 111 /** 112 * Create an instance with a custom imaginary character, and a custom number 113 * format for both real and imaginary parts. 114 * @param imaginaryCharacter The custom imaginary character. 115 * @param format the custom format for both real and imaginary parts. 116 * @throws NullArgumentException if {@code imaginaryCharacter} is 117 * {@code null}. 118 * @throws NoDataException if {@code imaginaryCharacter} is an 119 * empty string. 120 * @throws NullArgumentException if {@code format} is {@code null}. 121 */ 122 public ComplexFormat(String imaginaryCharacter, NumberFormat format) 123 throws NullArgumentException, NoDataException { 124 this(imaginaryCharacter, format, format); 125 } 126 127 /** 128 * Create an instance with a custom imaginary character, a custom number 129 * format for the real part, and a custom number format for the imaginary 130 * part. 131 * 132 * @param imaginaryCharacter The custom imaginary character. 133 * @param realFormat the custom format for the real part. 134 * @param imaginaryFormat the custom format for the imaginary part. 135 * @throws NullArgumentException if {@code imaginaryCharacter} is 136 * {@code null}. 137 * @throws NoDataException if {@code imaginaryCharacter} is an 138 * empty string. 139 * @throws NullArgumentException if {@code imaginaryFormat} is {@code null}. 140 * @throws NullArgumentException if {@code realFormat} is {@code null}. 141 */ 142 public ComplexFormat(String imaginaryCharacter, 143 NumberFormat realFormat, 144 NumberFormat imaginaryFormat) 145 throws NullArgumentException, NoDataException { 146 if (imaginaryCharacter == null) { 147 throw new NullArgumentException(); 148 } 149 if (imaginaryCharacter.length() == 0) { 150 throw new NoDataException(); 151 } 152 if (imaginaryFormat == null) { 153 throw new NullArgumentException(LocalizedFormats.IMAGINARY_FORMAT); 154 } 155 if (realFormat == null) { 156 throw new NullArgumentException(LocalizedFormats.REAL_FORMAT); 157 } 158 159 this.imaginaryCharacter = imaginaryCharacter; 160 this.imaginaryFormat = imaginaryFormat; 161 this.realFormat = realFormat; 162 } 163 164 /** 165 * Get the set of locales for which complex formats are available. 166 * <p>This is the same set as the {@link NumberFormat} set.</p> 167 * @return available complex format locales. 168 */ 169 public static Locale[] getAvailableLocales() { 170 return NumberFormat.getAvailableLocales(); 171 } 172 173 /** 174 * This method calls {@link #format(Object,StringBuffer,FieldPosition)}. 175 * 176 * @param c Complex object to format. 177 * @return A formatted number in the form "Re(c) + Im(c)i". 178 */ 179 public String format(Complex c) { 180 return format(c, new StringBuffer(), new FieldPosition(0)).toString(); 181 } 182 183 /** 184 * This method calls {@link #format(Object,StringBuffer,FieldPosition)}. 185 * 186 * @param c Double object to format. 187 * @return A formatted number. 188 */ 189 public String format(Double c) { 190 return format(new Complex(c, 0), new StringBuffer(), new FieldPosition(0)).toString(); 191 } 192 193 /** 194 * Formats a {@link Complex} object to produce a string. 195 * 196 * @param complex the object to format. 197 * @param toAppendTo where the text is to be appended 198 * @param pos On input: an alignment field, if desired. On output: the 199 * offsets of the alignment field 200 * @return the value passed in as toAppendTo. 201 */ 202 public StringBuffer format(Complex complex, StringBuffer toAppendTo, 203 FieldPosition pos) { 204 pos.setBeginIndex(0); 205 pos.setEndIndex(0); 206 207 // format real 208 double re = complex.getReal(); 209 CompositeFormat.formatDouble(re, getRealFormat(), toAppendTo, pos); 210 211 // format sign and imaginary 212 double im = complex.getImaginary(); 213 StringBuffer imAppendTo; 214 if (im < 0.0) { 215 toAppendTo.append(" - "); 216 imAppendTo = formatImaginary(-im, new StringBuffer(), pos); 217 toAppendTo.append(imAppendTo); 218 toAppendTo.append(getImaginaryCharacter()); 219 } else if (im > 0.0 || Double.isNaN(im)) { 220 toAppendTo.append(" + "); 221 imAppendTo = formatImaginary(im, new StringBuffer(), pos); 222 toAppendTo.append(imAppendTo); 223 toAppendTo.append(getImaginaryCharacter()); 224 } 225 226 return toAppendTo; 227 } 228 229 /** 230 * Format the absolute value of the imaginary part. 231 * 232 * @param absIm Absolute value of the imaginary part of a complex number. 233 * @param toAppendTo where the text is to be appended. 234 * @param pos On input: an alignment field, if desired. On output: the 235 * offsets of the alignment field. 236 * @return the value passed in as toAppendTo. 237 */ 238 private StringBuffer formatImaginary(double absIm, 239 StringBuffer toAppendTo, 240 FieldPosition pos) { 241 pos.setBeginIndex(0); 242 pos.setEndIndex(0); 243 244 CompositeFormat.formatDouble(absIm, getImaginaryFormat(), toAppendTo, pos); 245 if (toAppendTo.toString().equals("1")) { 246 // Remove the character "1" if it is the only one. 247 toAppendTo.setLength(0); 248 } 249 250 return toAppendTo; 251 } 252 253 /** 254 * Formats a object to produce a string. {@code obj} must be either a 255 * {@link Complex} object or a {@link Number} object. Any other type of 256 * object will result in an {@link IllegalArgumentException} being thrown. 257 * 258 * @param obj the object to format. 259 * @param toAppendTo where the text is to be appended 260 * @param pos On input: an alignment field, if desired. On output: the 261 * offsets of the alignment field 262 * @return the value passed in as toAppendTo. 263 * @see java.text.Format#format(java.lang.Object, java.lang.StringBuffer, java.text.FieldPosition) 264 * @throws MathIllegalArgumentException is {@code obj} is not a valid type. 265 */ 266 public StringBuffer format(Object obj, StringBuffer toAppendTo, 267 FieldPosition pos) 268 throws MathIllegalArgumentException { 269 270 StringBuffer ret = null; 271 272 if (obj instanceof Complex) { 273 ret = format( (Complex)obj, toAppendTo, pos); 274 } else if (obj instanceof Number) { 275 ret = format(new Complex(((Number)obj).doubleValue(), 0.0), 276 toAppendTo, pos); 277 } else { 278 throw new MathIllegalArgumentException(LocalizedFormats.CANNOT_FORMAT_INSTANCE_AS_COMPLEX, 279 obj.getClass().getName()); 280 } 281 282 return ret; 283 } 284 285 /** 286 * Access the imaginaryCharacter. 287 * @return the imaginaryCharacter. 288 */ 289 public String getImaginaryCharacter() { 290 return imaginaryCharacter; 291 } 292 293 /** 294 * Access the imaginaryFormat. 295 * @return the imaginaryFormat. 296 */ 297 public NumberFormat getImaginaryFormat() { 298 return imaginaryFormat; 299 } 300 301 /** 302 * Returns the default complex format for the current locale. 303 * @return the default complex format. 304 */ 305 public static ComplexFormat getInstance() { 306 return getInstance(Locale.getDefault()); 307 } 308 309 /** 310 * Returns the default complex format for the given locale. 311 * @param locale the specific locale used by the format. 312 * @return the complex format specific to the given locale. 313 */ 314 public static ComplexFormat getInstance(Locale locale) { 315 NumberFormat f = CompositeFormat.getDefaultNumberFormat(locale); 316 return new ComplexFormat(f); 317 } 318 319 /** 320 * Returns the default complex format for the given locale. 321 * @param locale the specific locale used by the format. 322 * @param imaginaryCharacter Imaginary character. 323 * @return the complex format specific to the given locale. 324 * @throws NullArgumentException if {@code imaginaryCharacter} is 325 * {@code null}. 326 * @throws NoDataException if {@code imaginaryCharacter} is an 327 * empty string. 328 */ 329 public static ComplexFormat getInstance(String imaginaryCharacter, Locale locale) 330 throws NullArgumentException, NoDataException { 331 NumberFormat f = CompositeFormat.getDefaultNumberFormat(locale); 332 return new ComplexFormat(imaginaryCharacter, f); 333 } 334 335 /** 336 * Access the realFormat. 337 * @return the realFormat. 338 */ 339 public NumberFormat getRealFormat() { 340 return realFormat; 341 } 342 343 /** 344 * Parses a string to produce a {@link Complex} object. 345 * 346 * @param source the string to parse. 347 * @return the parsed {@link Complex} object. 348 * @throws MathParseException if the beginning of the specified string 349 * cannot be parsed. 350 */ 351 public Complex parse(String source) throws MathParseException { 352 ParsePosition parsePosition = new ParsePosition(0); 353 Complex result = parse(source, parsePosition); 354 if (parsePosition.getIndex() == 0) { 355 throw new MathParseException(source, 356 parsePosition.getErrorIndex(), 357 Complex.class); 358 } 359 return result; 360 } 361 362 /** 363 * Parses a string to produce a {@link Complex} object. 364 * 365 * @param source the string to parse 366 * @param pos input/ouput parsing parameter. 367 * @return the parsed {@link Complex} object. 368 */ 369 public Complex parse(String source, ParsePosition pos) { 370 int initialIndex = pos.getIndex(); 371 372 // parse whitespace 373 CompositeFormat.parseAndIgnoreWhitespace(source, pos); 374 375 // parse real 376 Number re = CompositeFormat.parseNumber(source, getRealFormat(), pos); 377 if (re == null) { 378 // invalid real number 379 // set index back to initial, error index should already be set 380 pos.setIndex(initialIndex); 381 return null; 382 } 383 384 // parse sign 385 int startIndex = pos.getIndex(); 386 char c = CompositeFormat.parseNextCharacter(source, pos); 387 int sign = 0; 388 switch (c) { 389 case 0 : 390 // no sign 391 // return real only complex number 392 return new Complex(re.doubleValue(), 0.0); 393 case '-' : 394 sign = -1; 395 break; 396 case '+' : 397 sign = 1; 398 break; 399 default : 400 // invalid sign 401 // set index back to initial, error index should be the last 402 // character examined. 403 pos.setIndex(initialIndex); 404 pos.setErrorIndex(startIndex); 405 return null; 406 } 407 408 // parse whitespace 409 CompositeFormat.parseAndIgnoreWhitespace(source, pos); 410 411 // parse imaginary 412 Number im = CompositeFormat.parseNumber(source, getRealFormat(), pos); 413 if (im == null) { 414 // invalid imaginary number 415 // set index back to initial, error index should already be set 416 pos.setIndex(initialIndex); 417 return null; 418 } 419 420 // parse imaginary character 421 if (!CompositeFormat.parseFixedstring(source, getImaginaryCharacter(), pos)) { 422 return null; 423 } 424 425 return new Complex(re.doubleValue(), im.doubleValue() * sign); 426 427 } 428 }