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 * @author Apache Software Foundation 035 * @version $Revision: 772119 $ $Date: 2009-05-06 05:43:28 -0400 (Wed, 06 May 2009) $ 036 */ 037 public class ComplexFormat extends CompositeFormat { 038 039 /** Serializable version identifier */ 040 private static final long serialVersionUID = -3343698360149467646L; 041 042 /** The default imaginary character. */ 043 private static final String DEFAULT_IMAGINARY_CHARACTER = "i"; 044 045 /** The notation used to signify the imaginary part of the complex number. */ 046 private String imaginaryCharacter; 047 048 /** The format used for the imaginary part. */ 049 private NumberFormat imaginaryFormat; 050 051 /** The format used for the real part. */ 052 private NumberFormat realFormat; 053 054 /** 055 * Create an instance with the default imaginary character, 'i', and the 056 * default number format for both real and imaginary parts. 057 */ 058 public ComplexFormat() { 059 this(DEFAULT_IMAGINARY_CHARACTER, getDefaultNumberFormat()); 060 } 061 062 /** 063 * Create an instance with a custom number format for both real and 064 * imaginary parts. 065 * @param format the custom format for both real and imaginary parts. 066 */ 067 public ComplexFormat(NumberFormat format) { 068 this(DEFAULT_IMAGINARY_CHARACTER, format); 069 } 070 071 /** 072 * Create an instance with a custom number format for the real part and a 073 * custom number format for the imaginary part. 074 * @param realFormat the custom format for the real part. 075 * @param imaginaryFormat the custom format for the imaginary part. 076 */ 077 public ComplexFormat(NumberFormat realFormat, NumberFormat imaginaryFormat) { 078 this(DEFAULT_IMAGINARY_CHARACTER, realFormat, imaginaryFormat); 079 } 080 081 /** 082 * Create an instance with a custom imaginary character, and the default 083 * number format for both real and imaginary parts. 084 * @param imaginaryCharacter The custom imaginary character. 085 */ 086 public ComplexFormat(String imaginaryCharacter) { 087 this(imaginaryCharacter, getDefaultNumberFormat()); 088 } 089 090 /** 091 * Create an instance with a custom imaginary character, and a custom number 092 * format for both real and imaginary parts. 093 * @param imaginaryCharacter The custom imaginary character. 094 * @param format the custom format for both real and imaginary parts. 095 */ 096 public ComplexFormat(String imaginaryCharacter, NumberFormat format) { 097 this(imaginaryCharacter, format, (NumberFormat)format.clone()); 098 } 099 100 /** 101 * Create an instance with a custom imaginary character, a custom number 102 * format for the real part, and a custom number format for the imaginary 103 * part. 104 * @param imaginaryCharacter The custom imaginary character. 105 * @param realFormat the custom format for the real part. 106 * @param imaginaryFormat the custom format for the imaginary part. 107 */ 108 public ComplexFormat(String imaginaryCharacter, NumberFormat realFormat, 109 NumberFormat imaginaryFormat) { 110 super(); 111 setImaginaryCharacter(imaginaryCharacter); 112 setImaginaryFormat(imaginaryFormat); 113 setRealFormat(realFormat); 114 } 115 116 /** 117 * Get the set of locales for which complex formats are available. 118 * <p>This is the same set as the {@link NumberFormat} set.</p> 119 * @return available complex format locales. 120 */ 121 public static Locale[] getAvailableLocales() { 122 return NumberFormat.getAvailableLocales(); 123 } 124 125 /** 126 * This static method calls {@link #format(Object)} on a default instance of 127 * ComplexFormat. 128 * 129 * @param c Complex object to format 130 * @return A formatted number in the form "Re(c) + Im(c)i" 131 */ 132 public static String formatComplex(Complex c) { 133 return getInstance().format(c); 134 } 135 136 /** 137 * Formats a {@link Complex} object to produce a string. 138 * 139 * @param complex the object to format. 140 * @param toAppendTo where the text is to be appended 141 * @param pos On input: an alignment field, if desired. On output: the 142 * offsets of the alignment field 143 * @return the value passed in as toAppendTo. 144 */ 145 public StringBuffer format(Complex complex, StringBuffer toAppendTo, 146 FieldPosition pos) { 147 148 pos.setBeginIndex(0); 149 pos.setEndIndex(0); 150 151 // format real 152 double re = complex.getReal(); 153 formatDouble(re, getRealFormat(), toAppendTo, pos); 154 155 // format sign and imaginary 156 double im = complex.getImaginary(); 157 if (im < 0.0) { 158 toAppendTo.append(" - "); 159 formatDouble(-im, getImaginaryFormat(), toAppendTo, pos); 160 toAppendTo.append(getImaginaryCharacter()); 161 } else if (im > 0.0 || Double.isNaN(im)) { 162 toAppendTo.append(" + "); 163 formatDouble(im, getImaginaryFormat(), toAppendTo, pos); 164 toAppendTo.append(getImaginaryCharacter()); 165 } 166 167 return toAppendTo; 168 } 169 170 /** 171 * Formats a object to produce a string. <code>obj</code> must be either a 172 * {@link Complex} object or a {@link Number} object. Any other type of 173 * object will result in an {@link IllegalArgumentException} being thrown. 174 * 175 * @param obj the object to format. 176 * @param toAppendTo where the text is to be appended 177 * @param pos On input: an alignment field, if desired. On output: the 178 * offsets of the alignment field 179 * @return the value passed in as toAppendTo. 180 * @see java.text.Format#format(java.lang.Object, java.lang.StringBuffer, java.text.FieldPosition) 181 * @throws IllegalArgumentException is <code>obj</code> is not a valid type. 182 */ 183 @Override 184 public StringBuffer format(Object obj, StringBuffer toAppendTo, 185 FieldPosition pos) { 186 187 StringBuffer ret = null; 188 189 if (obj instanceof Complex) { 190 ret = format( (Complex)obj, toAppendTo, pos); 191 } else if (obj instanceof Number) { 192 ret = format( new Complex(((Number)obj).doubleValue(), 0.0), 193 toAppendTo, pos); 194 } else { 195 throw MathRuntimeException.createIllegalArgumentException( 196 "cannot format a {0} instance as a complex number", 197 obj.getClass().getName()); 198 } 199 200 return ret; 201 } 202 203 /** 204 * Access the imaginaryCharacter. 205 * @return the imaginaryCharacter. 206 */ 207 public String getImaginaryCharacter() { 208 return imaginaryCharacter; 209 } 210 211 /** 212 * Access the imaginaryFormat. 213 * @return the imaginaryFormat. 214 */ 215 public NumberFormat getImaginaryFormat() { 216 return imaginaryFormat; 217 } 218 219 /** 220 * Returns the default complex format for the current locale. 221 * @return the default complex format. 222 */ 223 public static ComplexFormat getInstance() { 224 return getInstance(Locale.getDefault()); 225 } 226 227 /** 228 * Returns the default complex format for the given locale. 229 * @param locale the specific locale used by the format. 230 * @return the complex format specific to the given locale. 231 */ 232 public static ComplexFormat getInstance(Locale locale) { 233 NumberFormat f = getDefaultNumberFormat(locale); 234 return new ComplexFormat(f); 235 } 236 237 /** 238 * Access the realFormat. 239 * @return the realFormat. 240 */ 241 public NumberFormat getRealFormat() { 242 return realFormat; 243 } 244 245 /** 246 * Parses a string to produce a {@link Complex} object. 247 * 248 * @param source the string to parse 249 * @return the parsed {@link Complex} object. 250 * @exception ParseException if the beginning of the specified string 251 * cannot be parsed. 252 */ 253 public Complex parse(String source) throws ParseException { 254 ParsePosition parsePosition = new ParsePosition(0); 255 Complex result = parse(source, parsePosition); 256 if (parsePosition.getIndex() == 0) { 257 throw MathRuntimeException.createParseException( 258 parsePosition.getErrorIndex(), 259 "unparseable complex number: \"{0}\"", source); 260 } 261 return result; 262 } 263 264 /** 265 * Parses a string to produce a {@link Complex} object. 266 * 267 * @param source the string to parse 268 * @param pos input/ouput parsing parameter. 269 * @return the parsed {@link Complex} object. 270 */ 271 public Complex parse(String source, ParsePosition pos) { 272 int initialIndex = pos.getIndex(); 273 274 // parse whitespace 275 parseAndIgnoreWhitespace(source, pos); 276 277 // parse real 278 Number re = parseNumber(source, getRealFormat(), pos); 279 if (re == null) { 280 // invalid real number 281 // set index back to initial, error index should already be set 282 pos.setIndex(initialIndex); 283 return null; 284 } 285 286 // parse sign 287 int startIndex = pos.getIndex(); 288 char c = parseNextCharacter(source, pos); 289 int sign = 0; 290 switch (c) { 291 case 0 : 292 // no sign 293 // return real only complex number 294 return new Complex(re.doubleValue(), 0.0); 295 case '-' : 296 sign = -1; 297 break; 298 case '+' : 299 sign = 1; 300 break; 301 default : 302 // invalid sign 303 // set index back to initial, error index should be the last 304 // character examined. 305 pos.setIndex(initialIndex); 306 pos.setErrorIndex(startIndex); 307 return null; 308 } 309 310 // parse whitespace 311 parseAndIgnoreWhitespace(source, pos); 312 313 // parse imaginary 314 Number im = parseNumber(source, getRealFormat(), pos); 315 if (im == null) { 316 // invalid imaginary number 317 // set index back to initial, error index should already be set 318 pos.setIndex(initialIndex); 319 return null; 320 } 321 322 // parse imaginary character 323 if (!parseFixedstring(source, getImaginaryCharacter(), pos)) { 324 return null; 325 } 326 327 return new Complex(re.doubleValue(), im.doubleValue() * sign); 328 329 } 330 331 /** 332 * Parses a string to produce a object. 333 * 334 * @param source the string to parse 335 * @param pos input/ouput parsing parameter. 336 * @return the parsed object. 337 * @see java.text.Format#parseObject(java.lang.String, java.text.ParsePosition) 338 */ 339 @Override 340 public Object parseObject(String source, ParsePosition pos) { 341 return parse(source, pos); 342 } 343 344 /** 345 * Modify the imaginaryCharacter. 346 * @param imaginaryCharacter The new imaginaryCharacter value. 347 * @throws IllegalArgumentException if <code>imaginaryCharacter</code> is 348 * <code>null</code> or an empty string. 349 */ 350 public void setImaginaryCharacter(String imaginaryCharacter) { 351 if (imaginaryCharacter == null || imaginaryCharacter.length() == 0) { 352 throw MathRuntimeException.createIllegalArgumentException( 353 "empty string for imaginary character"); 354 } 355 this.imaginaryCharacter = imaginaryCharacter; 356 } 357 358 /** 359 * Modify the imaginaryFormat. 360 * @param imaginaryFormat The new imaginaryFormat value. 361 * @throws IllegalArgumentException if <code>imaginaryFormat</code> is 362 * <code>null</code>. 363 */ 364 public void setImaginaryFormat(NumberFormat imaginaryFormat) { 365 if (imaginaryFormat == null) { 366 throw MathRuntimeException.createIllegalArgumentException( 367 "null imaginary format"); 368 } 369 this.imaginaryFormat = imaginaryFormat; 370 } 371 372 /** 373 * Modify the realFormat. 374 * @param realFormat The new realFormat value. 375 * @throws IllegalArgumentException if <code>realFormat</code> is 376 * <code>null</code>. 377 */ 378 public void setRealFormat(NumberFormat realFormat) { 379 if (realFormat == null) { 380 throw MathRuntimeException.createIllegalArgumentException( 381 "null real format"); 382 } 383 this.realFormat = realFormat; 384 } 385 386 }