1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 18 package org.apache.commons.math.complex; 19 20 import java.text.FieldPosition; 21 import java.text.NumberFormat; 22 import java.text.ParseException; 23 import java.text.ParsePosition; 24 import java.util.Locale; 25 26 import org.apache.commons.math.MathRuntimeException; 27 import org.apache.commons.math.exception.util.LocalizedFormats; 28 import org.apache.commons.math.util.CompositeFormat; 29 import org.apache.commons.math.exception.NullArgumentException; 30 31 /** 32 * Formats a Complex number in cartesian format "Re(c) + Im(c)i". 'i' can 33 * be replaced with 'j' (or anything else), and the number format for both real 34 * and imaginary parts can be configured. 35 * 36 * @version $Revision: 983921 $ $Date: 2010-08-10 12:46:06 +0200 (mar. 10 aot 2010) $ 37 */ 38 public class ComplexFormat extends CompositeFormat { 39 40 /** Serializable version identifier */ 41 private static final long serialVersionUID = -3343698360149467646L; 42 43 /** The default imaginary character. */ 44 private static final String DEFAULT_IMAGINARY_CHARACTER = "i"; 45 46 /** The notation used to signify the imaginary part of the complex number. */ 47 private String imaginaryCharacter; 48 49 /** The format used for the imaginary part. */ 50 private NumberFormat imaginaryFormat; 51 52 /** The format used for the real part. */ 53 private NumberFormat realFormat; 54 55 /** 56 * Create an instance with the default imaginary character, 'i', and the 57 * default number format for both real and imaginary parts. 58 */ 59 public ComplexFormat() { 60 this(DEFAULT_IMAGINARY_CHARACTER, getDefaultNumberFormat()); 61 } 62 63 /** 64 * Create an instance with a custom number format for both real and 65 * imaginary parts. 66 * @param format the custom format for both real and imaginary parts. 67 */ 68 public ComplexFormat(NumberFormat format) { 69 this(DEFAULT_IMAGINARY_CHARACTER, format); 70 } 71 72 /** 73 * Create an instance with a custom number format for the real part and a 74 * custom number format for the imaginary part. 75 * @param realFormat the custom format for the real part. 76 * @param imaginaryFormat the custom format for the imaginary part. 77 */ 78 public ComplexFormat(NumberFormat realFormat, NumberFormat imaginaryFormat) { 79 this(DEFAULT_IMAGINARY_CHARACTER, realFormat, imaginaryFormat); 80 } 81 82 /** 83 * Create an instance with a custom imaginary character, and the default 84 * number format for both real and imaginary parts. 85 * @param imaginaryCharacter The custom imaginary character. 86 */ 87 public ComplexFormat(String imaginaryCharacter) { 88 this(imaginaryCharacter, getDefaultNumberFormat()); 89 } 90 91 /** 92 * Create an instance with a custom imaginary character, and a custom number 93 * format for both real and imaginary parts. 94 * @param imaginaryCharacter The custom imaginary character. 95 * @param format the custom format for both real and imaginary parts. 96 */ 97 public ComplexFormat(String imaginaryCharacter, NumberFormat format) { 98 this(imaginaryCharacter, format, (NumberFormat)format.clone()); 99 } 100 101 /** 102 * Create an instance with a custom imaginary character, a custom number 103 * format for the real part, and a custom number format for the imaginary 104 * part. 105 * @param imaginaryCharacter The custom imaginary character. 106 * @param realFormat the custom format for the real part. 107 * @param imaginaryFormat the custom format for the imaginary part. 108 */ 109 public ComplexFormat(String imaginaryCharacter, NumberFormat realFormat, 110 NumberFormat imaginaryFormat) { 111 super(); 112 setImaginaryCharacter(imaginaryCharacter); 113 setImaginaryFormat(imaginaryFormat); 114 setRealFormat(realFormat); 115 } 116 117 /** 118 * Get the set of locales for which complex formats are available. 119 * <p>This is the same set as the {@link NumberFormat} set.</p> 120 * @return available complex format locales. 121 */ 122 public static Locale[] getAvailableLocales() { 123 return NumberFormat.getAvailableLocales(); 124 } 125 126 /** 127 * This static method calls {@link #format(Object)} on a default instance of 128 * ComplexFormat. 129 * 130 * @param c Complex object to format 131 * @return A formatted number in the form "Re(c) + Im(c)i" 132 */ 133 public static String formatComplex(Complex c) { 134 return getInstance().format(c); 135 } 136 137 /** 138 * Formats a {@link Complex} object to produce a string. 139 * 140 * @param complex the object to format. 141 * @param toAppendTo where the text is to be appended 142 * @param pos On input: an alignment field, if desired. On output: the 143 * offsets of the alignment field 144 * @return the value passed in as toAppendTo. 145 */ 146 public StringBuffer format(Complex complex, StringBuffer toAppendTo, 147 FieldPosition pos) { 148 149 pos.setBeginIndex(0); 150 pos.setEndIndex(0); 151 152 // format real 153 double re = complex.getReal(); 154 formatDouble(re, getRealFormat(), toAppendTo, pos); 155 156 // format sign and imaginary 157 double im = complex.getImaginary(); 158 if (im < 0.0) { 159 toAppendTo.append(" - "); 160 formatDouble(-im, getImaginaryFormat(), toAppendTo, pos); 161 toAppendTo.append(getImaginaryCharacter()); 162 } else if (im > 0.0 || Double.isNaN(im)) { 163 toAppendTo.append(" + "); 164 formatDouble(im, getImaginaryFormat(), toAppendTo, pos); 165 toAppendTo.append(getImaginaryCharacter()); 166 } 167 168 return toAppendTo; 169 } 170 171 /** 172 * Formats a object to produce a string. <code>obj</code> must be either a 173 * {@link Complex} object or a {@link Number} object. Any other type of 174 * object will result in an {@link IllegalArgumentException} being thrown. 175 * 176 * @param obj the object to format. 177 * @param toAppendTo where the text is to be appended 178 * @param pos On input: an alignment field, if desired. On output: the 179 * offsets of the alignment field 180 * @return the value passed in as toAppendTo. 181 * @see java.text.Format#format(java.lang.Object, java.lang.StringBuffer, java.text.FieldPosition) 182 * @throws IllegalArgumentException is <code>obj</code> is not a valid type. 183 */ 184 @Override 185 public StringBuffer format(Object obj, StringBuffer toAppendTo, 186 FieldPosition pos) { 187 188 StringBuffer ret = null; 189 190 if (obj instanceof Complex) { 191 ret = format( (Complex)obj, toAppendTo, pos); 192 } else if (obj instanceof Number) { 193 ret = format( new Complex(((Number)obj).doubleValue(), 0.0), 194 toAppendTo, pos); 195 } else { 196 throw MathRuntimeException.createIllegalArgumentException( 197 LocalizedFormats.CANNOT_FORMAT_INSTANCE_AS_COMPLEX, 198 obj.getClass().getName()); 199 } 200 201 return ret; 202 } 203 204 /** 205 * Access the imaginaryCharacter. 206 * @return the imaginaryCharacter. 207 */ 208 public String getImaginaryCharacter() { 209 return imaginaryCharacter; 210 } 211 212 /** 213 * Access the imaginaryFormat. 214 * @return the imaginaryFormat. 215 */ 216 public NumberFormat getImaginaryFormat() { 217 return imaginaryFormat; 218 } 219 220 /** 221 * Returns the default complex format for the current locale. 222 * @return the default complex format. 223 */ 224 public static ComplexFormat getInstance() { 225 return getInstance(Locale.getDefault()); 226 } 227 228 /** 229 * Returns the default complex format for the given locale. 230 * @param locale the specific locale used by the format. 231 * @return the complex format specific to the given locale. 232 */ 233 public static ComplexFormat getInstance(Locale locale) { 234 NumberFormat f = getDefaultNumberFormat(locale); 235 return new ComplexFormat(f); 236 } 237 238 /** 239 * Access the realFormat. 240 * @return the realFormat. 241 */ 242 public NumberFormat getRealFormat() { 243 return realFormat; 244 } 245 246 /** 247 * Parses a string to produce a {@link Complex} object. 248 * 249 * @param source the string to parse 250 * @return the parsed {@link Complex} object. 251 * @exception ParseException if the beginning of the specified string 252 * cannot be parsed. 253 */ 254 public Complex parse(String source) throws ParseException { 255 ParsePosition parsePosition = new ParsePosition(0); 256 Complex result = parse(source, parsePosition); 257 if (parsePosition.getIndex() == 0) { 258 throw MathRuntimeException.createParseException( 259 parsePosition.getErrorIndex(), 260 LocalizedFormats.UNPARSEABLE_COMPLEX_NUMBER, source); 261 } 262 return result; 263 } 264 265 /** 266 * Parses a string to produce a {@link Complex} object. 267 * 268 * @param source the string to parse 269 * @param pos input/ouput parsing parameter. 270 * @return the parsed {@link Complex} object. 271 */ 272 public Complex parse(String source, ParsePosition pos) { 273 int initialIndex = pos.getIndex(); 274 275 // parse whitespace 276 parseAndIgnoreWhitespace(source, pos); 277 278 // parse real 279 Number re = parseNumber(source, getRealFormat(), pos); 280 if (re == null) { 281 // invalid real number 282 // set index back to initial, error index should already be set 283 pos.setIndex(initialIndex); 284 return null; 285 } 286 287 // parse sign 288 int startIndex = pos.getIndex(); 289 char c = parseNextCharacter(source, pos); 290 int sign = 0; 291 switch (c) { 292 case 0 : 293 // no sign 294 // return real only complex number 295 return new Complex(re.doubleValue(), 0.0); 296 case '-' : 297 sign = -1; 298 break; 299 case '+' : 300 sign = 1; 301 break; 302 default : 303 // invalid sign 304 // set index back to initial, error index should be the last 305 // character examined. 306 pos.setIndex(initialIndex); 307 pos.setErrorIndex(startIndex); 308 return null; 309 } 310 311 // parse whitespace 312 parseAndIgnoreWhitespace(source, pos); 313 314 // parse imaginary 315 Number im = parseNumber(source, getRealFormat(), pos); 316 if (im == null) { 317 // invalid imaginary number 318 // set index back to initial, error index should already be set 319 pos.setIndex(initialIndex); 320 return null; 321 } 322 323 // parse imaginary character 324 if (!parseFixedstring(source, getImaginaryCharacter(), pos)) { 325 return null; 326 } 327 328 return new Complex(re.doubleValue(), im.doubleValue() * sign); 329 330 } 331 332 /** 333 * Parses a string to produce a object. 334 * 335 * @param source the string to parse 336 * @param pos input/ouput parsing parameter. 337 * @return the parsed object. 338 * @see java.text.Format#parseObject(java.lang.String, java.text.ParsePosition) 339 */ 340 @Override 341 public Object parseObject(String source, ParsePosition pos) { 342 return parse(source, pos); 343 } 344 345 /** 346 * Modify the imaginaryCharacter. 347 * @param imaginaryCharacter The new imaginaryCharacter value. 348 * @throws IllegalArgumentException if <code>imaginaryCharacter</code> is 349 * <code>null</code> or an empty string. 350 */ 351 public void setImaginaryCharacter(String imaginaryCharacter) { 352 if (imaginaryCharacter == null || imaginaryCharacter.length() == 0) { 353 throw MathRuntimeException.createIllegalArgumentException( 354 LocalizedFormats.EMPTY_STRING_FOR_IMAGINARY_CHARACTER); 355 } 356 this.imaginaryCharacter = imaginaryCharacter; 357 } 358 359 /** 360 * Modify the imaginaryFormat. 361 * @param imaginaryFormat The new imaginaryFormat value. 362 * @throws NullArgumentException if {@code imaginaryFormat} is {@code null}. 363 */ 364 public void setImaginaryFormat(NumberFormat imaginaryFormat) { 365 if (imaginaryFormat == null) { 366 throw new NullArgumentException(LocalizedFormats.IMAGINARY_FORMAT); 367 } 368 this.imaginaryFormat = imaginaryFormat; 369 } 370 371 /** 372 * Modify the realFormat. 373 * @param realFormat The new realFormat value. 374 * @throws NullArgumentException if {@code realFormat} is {@code null}. 375 */ 376 public void setRealFormat(NumberFormat realFormat) { 377 if (realFormat == null) { 378 throw new NullArgumentException(LocalizedFormats.REAL_FORMAT); 379 } 380 this.realFormat = realFormat; 381 } 382 383 } 384