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.exception.util.LocalizedFormats;
028    import org.apache.commons.math.util.CompositeFormat;
029    import org.apache.commons.math.exception.NullArgumentException;
030    
031    /**
032     * Formats a Complex number in cartesian format "Re(c) + Im(c)i".  'i' can
033     * be replaced with 'j' (or anything else), and the number format for both real
034     * and imaginary parts can be configured.
035     *
036     * @version $Revision: 983921 $ $Date: 2010-08-10 12:46:06 +0200 (mar. 10 ao??t 2010) $
037     */
038    public class ComplexFormat extends CompositeFormat {
039    
040        /** Serializable version identifier */
041        private static final long serialVersionUID = -3343698360149467646L;
042    
043         /** The default imaginary character. */
044        private static final String DEFAULT_IMAGINARY_CHARACTER = "i";
045    
046        /** The notation used to signify the imaginary part of the complex number. */
047        private String imaginaryCharacter;
048    
049        /** The format used for the imaginary part. */
050        private NumberFormat imaginaryFormat;
051    
052        /** The format used for the real part. */
053        private NumberFormat realFormat;
054    
055        /**
056         * Create an instance with the default imaginary character, 'i', and the
057         * default number format for both real and imaginary parts.
058         */
059        public ComplexFormat() {
060            this(DEFAULT_IMAGINARY_CHARACTER, getDefaultNumberFormat());
061        }
062    
063        /**
064         * Create an instance with a custom number format for both real and
065         * imaginary parts.
066         * @param format the custom format for both real and imaginary parts.
067         */
068        public ComplexFormat(NumberFormat format) {
069            this(DEFAULT_IMAGINARY_CHARACTER, format);
070        }
071    
072        /**
073         * Create an instance with a custom number format for the real part and a
074         * custom number format for the imaginary part.
075         * @param realFormat the custom format for the real part.
076         * @param imaginaryFormat the custom format for the imaginary part.
077         */
078        public ComplexFormat(NumberFormat realFormat, NumberFormat imaginaryFormat) {
079            this(DEFAULT_IMAGINARY_CHARACTER, realFormat, imaginaryFormat);
080        }
081    
082        /**
083         * Create an instance with a custom imaginary character, and the default
084         * number format for both real and imaginary parts.
085         * @param imaginaryCharacter The custom imaginary character.
086         */
087        public ComplexFormat(String imaginaryCharacter) {
088            this(imaginaryCharacter, getDefaultNumberFormat());
089        }
090    
091        /**
092         * Create an instance with a custom imaginary character, and a custom number
093         * format for both real and imaginary parts.
094         * @param imaginaryCharacter The custom imaginary character.
095         * @param format the custom format for both real and imaginary parts.
096         */
097        public ComplexFormat(String imaginaryCharacter, NumberFormat format) {
098            this(imaginaryCharacter, format, (NumberFormat)format.clone());
099        }
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    }