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