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.math.complex; 019 020 import java.text.FieldPosition; 021 import java.text.NumberFormat; 022 import java.text.ParseException; 023 import java.text.ParsePosition; 024 import java.util.Locale; 025 026 import org.apache.commons.math.MathRuntimeException; 027 import org.apache.commons.math.util.CompositeFormat; 028 029 /** 030 * Formats a Complex number in cartesian format "Re(c) + Im(c)i". 'i' can 031 * be replaced with 'j' (or anything else), and the number format for both real 032 * and imaginary parts can be configured. 033 * 034 * @version $Revision: 811783 $ $Date: 2009-09-06 04:56:58 -0400 (Sun, 06 Sep 2009) $ 035 */ 036 public class ComplexFormat extends CompositeFormat { 037 038 /** Serializable version identifier */ 039 private static final long serialVersionUID = -3343698360149467646L; 040 041 /** The default imaginary character. */ 042 private static final String DEFAULT_IMAGINARY_CHARACTER = "i"; 043 044 /** The notation used to signify the imaginary part of the complex number. */ 045 private String imaginaryCharacter; 046 047 /** The format used for the imaginary part. */ 048 private NumberFormat imaginaryFormat; 049 050 /** The format used for the real part. */ 051 private NumberFormat realFormat; 052 053 /** 054 * Create an instance with the default imaginary character, 'i', and the 055 * default number format for both real and imaginary parts. 056 */ 057 public ComplexFormat() { 058 this(DEFAULT_IMAGINARY_CHARACTER, getDefaultNumberFormat()); 059 } 060 061 /** 062 * Create an instance with a custom number format for both real and 063 * imaginary parts. 064 * @param format the custom format for both real and imaginary parts. 065 */ 066 public ComplexFormat(NumberFormat format) { 067 this(DEFAULT_IMAGINARY_CHARACTER, format); 068 } 069 070 /** 071 * Create an instance with a custom number format for the real part and a 072 * custom number format for the imaginary part. 073 * @param realFormat the custom format for the real part. 074 * @param imaginaryFormat the custom format for the imaginary part. 075 */ 076 public ComplexFormat(NumberFormat realFormat, NumberFormat imaginaryFormat) { 077 this(DEFAULT_IMAGINARY_CHARACTER, realFormat, imaginaryFormat); 078 } 079 080 /** 081 * Create an instance with a custom imaginary character, and the default 082 * number format for both real and imaginary parts. 083 * @param imaginaryCharacter The custom imaginary character. 084 */ 085 public ComplexFormat(String imaginaryCharacter) { 086 this(imaginaryCharacter, getDefaultNumberFormat()); 087 } 088 089 /** 090 * Create an instance with a custom imaginary character, and a custom number 091 * format for both real and imaginary parts. 092 * @param imaginaryCharacter The custom imaginary character. 093 * @param format the custom format for both real and imaginary parts. 094 */ 095 public ComplexFormat(String imaginaryCharacter, NumberFormat format) { 096 this(imaginaryCharacter, format, (NumberFormat)format.clone()); 097 } 098 099 /** 100 * Create an instance with a custom imaginary character, a custom number 101 * format for the real part, and a custom number format for the imaginary 102 * part. 103 * @param imaginaryCharacter The custom imaginary character. 104 * @param realFormat the custom format for the real part. 105 * @param imaginaryFormat the custom format for the imaginary part. 106 */ 107 public ComplexFormat(String imaginaryCharacter, NumberFormat realFormat, 108 NumberFormat imaginaryFormat) { 109 super(); 110 setImaginaryCharacter(imaginaryCharacter); 111 setImaginaryFormat(imaginaryFormat); 112 setRealFormat(realFormat); 113 } 114 115 /** 116 * Get the set of locales for which complex formats are available. 117 * <p>This is the same set as the {@link NumberFormat} set.</p> 118 * @return available complex format locales. 119 */ 120 public static Locale[] getAvailableLocales() { 121 return NumberFormat.getAvailableLocales(); 122 } 123 124 /** 125 * This static method calls {@link #format(Object)} on a default instance of 126 * ComplexFormat. 127 * 128 * @param c Complex object to format 129 * @return A formatted number in the form "Re(c) + Im(c)i" 130 */ 131 public static String formatComplex(Complex c) { 132 return getInstance().format(c); 133 } 134 135 /** 136 * Formats a {@link Complex} object to produce a string. 137 * 138 * @param complex the object to format. 139 * @param toAppendTo where the text is to be appended 140 * @param pos On input: an alignment field, if desired. On output: the 141 * offsets of the alignment field 142 * @return the value passed in as toAppendTo. 143 */ 144 public StringBuffer format(Complex complex, StringBuffer toAppendTo, 145 FieldPosition pos) { 146 147 pos.setBeginIndex(0); 148 pos.setEndIndex(0); 149 150 // format real 151 double re = complex.getReal(); 152 formatDouble(re, getRealFormat(), toAppendTo, pos); 153 154 // format sign and imaginary 155 double im = complex.getImaginary(); 156 if (im < 0.0) { 157 toAppendTo.append(" - "); 158 formatDouble(-im, getImaginaryFormat(), toAppendTo, pos); 159 toAppendTo.append(getImaginaryCharacter()); 160 } else if (im > 0.0 || Double.isNaN(im)) { 161 toAppendTo.append(" + "); 162 formatDouble(im, getImaginaryFormat(), toAppendTo, pos); 163 toAppendTo.append(getImaginaryCharacter()); 164 } 165 166 return toAppendTo; 167 } 168 169 /** 170 * Formats a object to produce a string. <code>obj</code> must be either a 171 * {@link Complex} object or a {@link Number} object. Any other type of 172 * object will result in an {@link IllegalArgumentException} being thrown. 173 * 174 * @param obj the object to format. 175 * @param toAppendTo where the text is to be appended 176 * @param pos On input: an alignment field, if desired. On output: the 177 * offsets of the alignment field 178 * @return the value passed in as toAppendTo. 179 * @see java.text.Format#format(java.lang.Object, java.lang.StringBuffer, java.text.FieldPosition) 180 * @throws IllegalArgumentException is <code>obj</code> is not a valid type. 181 */ 182 @Override 183 public StringBuffer format(Object obj, StringBuffer toAppendTo, 184 FieldPosition pos) { 185 186 StringBuffer ret = null; 187 188 if (obj instanceof Complex) { 189 ret = format( (Complex)obj, toAppendTo, pos); 190 } else if (obj instanceof Number) { 191 ret = format( new Complex(((Number)obj).doubleValue(), 0.0), 192 toAppendTo, pos); 193 } else { 194 throw MathRuntimeException.createIllegalArgumentException( 195 "cannot format a {0} instance as a complex number", 196 obj.getClass().getName()); 197 } 198 199 return ret; 200 } 201 202 /** 203 * Access the imaginaryCharacter. 204 * @return the imaginaryCharacter. 205 */ 206 public String getImaginaryCharacter() { 207 return imaginaryCharacter; 208 } 209 210 /** 211 * Access the imaginaryFormat. 212 * @return the imaginaryFormat. 213 */ 214 public NumberFormat getImaginaryFormat() { 215 return imaginaryFormat; 216 } 217 218 /** 219 * Returns the default complex format for the current locale. 220 * @return the default complex format. 221 */ 222 public static ComplexFormat getInstance() { 223 return getInstance(Locale.getDefault()); 224 } 225 226 /** 227 * Returns the default complex format for the given locale. 228 * @param locale the specific locale used by the format. 229 * @return the complex format specific to the given locale. 230 */ 231 public static ComplexFormat getInstance(Locale locale) { 232 NumberFormat f = getDefaultNumberFormat(locale); 233 return new ComplexFormat(f); 234 } 235 236 /** 237 * Access the realFormat. 238 * @return the realFormat. 239 */ 240 public NumberFormat getRealFormat() { 241 return realFormat; 242 } 243 244 /** 245 * Parses a string to produce a {@link Complex} object. 246 * 247 * @param source the string to parse 248 * @return the parsed {@link Complex} object. 249 * @exception ParseException if the beginning of the specified string 250 * cannot be parsed. 251 */ 252 public Complex parse(String source) throws ParseException { 253 ParsePosition parsePosition = new ParsePosition(0); 254 Complex result = parse(source, parsePosition); 255 if (parsePosition.getIndex() == 0) { 256 throw MathRuntimeException.createParseException( 257 parsePosition.getErrorIndex(), 258 "unparseable complex number: \"{0}\"", source); 259 } 260 return result; 261 } 262 263 /** 264 * Parses a string to produce a {@link Complex} object. 265 * 266 * @param source the string to parse 267 * @param pos input/ouput parsing parameter. 268 * @return the parsed {@link Complex} object. 269 */ 270 public Complex parse(String source, ParsePosition pos) { 271 int initialIndex = pos.getIndex(); 272 273 // parse whitespace 274 parseAndIgnoreWhitespace(source, pos); 275 276 // parse real 277 Number re = parseNumber(source, getRealFormat(), pos); 278 if (re == null) { 279 // invalid real number 280 // set index back to initial, error index should already be set 281 pos.setIndex(initialIndex); 282 return null; 283 } 284 285 // parse sign 286 int startIndex = pos.getIndex(); 287 char c = parseNextCharacter(source, pos); 288 int sign = 0; 289 switch (c) { 290 case 0 : 291 // no sign 292 // return real only complex number 293 return new Complex(re.doubleValue(), 0.0); 294 case '-' : 295 sign = -1; 296 break; 297 case '+' : 298 sign = 1; 299 break; 300 default : 301 // invalid sign 302 // set index back to initial, error index should be the last 303 // character examined. 304 pos.setIndex(initialIndex); 305 pos.setErrorIndex(startIndex); 306 return null; 307 } 308 309 // parse whitespace 310 parseAndIgnoreWhitespace(source, pos); 311 312 // parse imaginary 313 Number im = parseNumber(source, getRealFormat(), pos); 314 if (im == null) { 315 // invalid imaginary number 316 // set index back to initial, error index should already be set 317 pos.setIndex(initialIndex); 318 return null; 319 } 320 321 // parse imaginary character 322 if (!parseFixedstring(source, getImaginaryCharacter(), pos)) { 323 return null; 324 } 325 326 return new Complex(re.doubleValue(), im.doubleValue() * sign); 327 328 } 329 330 /** 331 * Parses a string to produce a object. 332 * 333 * @param source the string to parse 334 * @param pos input/ouput parsing parameter. 335 * @return the parsed object. 336 * @see java.text.Format#parseObject(java.lang.String, java.text.ParsePosition) 337 */ 338 @Override 339 public Object parseObject(String source, ParsePosition pos) { 340 return parse(source, pos); 341 } 342 343 /** 344 * Modify the imaginaryCharacter. 345 * @param imaginaryCharacter The new imaginaryCharacter value. 346 * @throws IllegalArgumentException if <code>imaginaryCharacter</code> is 347 * <code>null</code> or an empty string. 348 */ 349 public void setImaginaryCharacter(String imaginaryCharacter) { 350 if (imaginaryCharacter == null || imaginaryCharacter.length() == 0) { 351 throw MathRuntimeException.createIllegalArgumentException( 352 "empty string for imaginary character"); 353 } 354 this.imaginaryCharacter = imaginaryCharacter; 355 } 356 357 /** 358 * Modify the imaginaryFormat. 359 * @param imaginaryFormat The new imaginaryFormat value. 360 * @throws IllegalArgumentException if <code>imaginaryFormat</code> is 361 * <code>null</code>. 362 */ 363 public void setImaginaryFormat(NumberFormat imaginaryFormat) { 364 if (imaginaryFormat == null) { 365 throw MathRuntimeException.createIllegalArgumentException( 366 "null imaginary format"); 367 } 368 this.imaginaryFormat = imaginaryFormat; 369 } 370 371 /** 372 * Modify the realFormat. 373 * @param realFormat The new realFormat value. 374 * @throws IllegalArgumentException if <code>realFormat</code> is 375 * <code>null</code>. 376 */ 377 public void setRealFormat(NumberFormat realFormat) { 378 if (realFormat == null) { 379 throw MathRuntimeException.createIllegalArgumentException( 380 "null real format"); 381 } 382 this.realFormat = realFormat; 383 } 384 385 }