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 * @version $Id: ComplexFormat.java 1416643 2012-12-03 19:37:14Z tn $
038 */
039public class ComplexFormat {
040
041     /** The default imaginary character. */
042    private static final String DEFAULT_IMAGINARY_CHARACTER = "i";
043    /** The notation used to signify the imaginary part of the complex number. */
044    private final String imaginaryCharacter;
045    /** The format used for the imaginary part. */
046    private final NumberFormat imaginaryFormat;
047    /** The format used for the real part. */
048    private final NumberFormat realFormat;
049
050    /**
051     * Create an instance with the default imaginary character, 'i', and the
052     * default number format for both real and imaginary parts.
053     */
054    public ComplexFormat() {
055        this.imaginaryCharacter = DEFAULT_IMAGINARY_CHARACTER;
056        this.imaginaryFormat = CompositeFormat.getDefaultNumberFormat();
057        this.realFormat = imaginaryFormat;
058    }
059
060    /**
061     * Create an instance with a custom number format for both real and
062     * imaginary parts.
063     * @param format the custom format for both real and imaginary parts.
064     * @throws NullArgumentException if {@code realFormat} is {@code null}.
065     */
066    public ComplexFormat(NumberFormat format) throws NullArgumentException {
067        if (format == null) {
068            throw new NullArgumentException(LocalizedFormats.IMAGINARY_FORMAT);
069        }
070        this.imaginaryCharacter = DEFAULT_IMAGINARY_CHARACTER;
071        this.imaginaryFormat = format;
072        this.realFormat = format;
073    }
074
075    /**
076     * Create an instance with a custom number format for the real part and a
077     * custom number format for the imaginary part.
078     * @param realFormat the custom format for the real part.
079     * @param imaginaryFormat the custom format for the imaginary part.
080     * @throws NullArgumentException if {@code imaginaryFormat} is {@code null}.
081     * @throws NullArgumentException if {@code realFormat} is {@code null}.
082      */
083    public ComplexFormat(NumberFormat realFormat, NumberFormat imaginaryFormat)
084        throws NullArgumentException {
085        if (imaginaryFormat == null) {
086            throw new NullArgumentException(LocalizedFormats.IMAGINARY_FORMAT);
087        }
088        if (realFormat == null) {
089            throw new NullArgumentException(LocalizedFormats.REAL_FORMAT);
090        }
091
092        this.imaginaryCharacter = DEFAULT_IMAGINARY_CHARACTER;
093        this.imaginaryFormat = imaginaryFormat;
094        this.realFormat = realFormat;
095    }
096
097    /**
098     * Create an instance with a custom imaginary character, and the default
099     * number format for both real and imaginary parts.
100     * @param imaginaryCharacter The custom imaginary character.
101     * @throws NullArgumentException if {@code imaginaryCharacter} is
102     * {@code null}.
103     * @throws NoDataException if {@code imaginaryCharacter} is an
104     * empty string.
105     */
106    public ComplexFormat(String imaginaryCharacter)
107        throws NullArgumentException, NoDataException {
108        this(imaginaryCharacter, CompositeFormat.getDefaultNumberFormat());
109    }
110
111    /**
112     * Create an instance with a custom imaginary character, and a custom number
113     * format for both real and imaginary parts.
114     * @param imaginaryCharacter The custom imaginary character.
115     * @param format the custom format for both real and imaginary parts.
116     * @throws NullArgumentException if {@code imaginaryCharacter} is
117     * {@code null}.
118     * @throws NoDataException if {@code imaginaryCharacter} is an
119     * empty string.
120     * @throws NullArgumentException if {@code format} is {@code null}.
121     */
122    public ComplexFormat(String imaginaryCharacter, NumberFormat format)
123        throws NullArgumentException, NoDataException {
124        this(imaginaryCharacter, format, format);
125    }
126
127    /**
128     * Create an instance with a custom imaginary character, a custom number
129     * format for the real part, and a custom number format for the imaginary
130     * part.
131     *
132     * @param imaginaryCharacter The custom imaginary character.
133     * @param realFormat the custom format for the real part.
134     * @param imaginaryFormat the custom format for the imaginary part.
135     * @throws NullArgumentException if {@code imaginaryCharacter} is
136     * {@code null}.
137     * @throws NoDataException if {@code imaginaryCharacter} is an
138     * empty string.
139     * @throws NullArgumentException if {@code imaginaryFormat} is {@code null}.
140     * @throws NullArgumentException if {@code realFormat} is {@code null}.
141     */
142    public ComplexFormat(String imaginaryCharacter,
143                         NumberFormat realFormat,
144                         NumberFormat imaginaryFormat)
145        throws NullArgumentException, NoDataException {
146        if (imaginaryCharacter == null) {
147            throw new NullArgumentException();
148        }
149        if (imaginaryCharacter.length() == 0) {
150            throw new NoDataException();
151        }
152        if (imaginaryFormat == null) {
153            throw new NullArgumentException(LocalizedFormats.IMAGINARY_FORMAT);
154        }
155        if (realFormat == null) {
156            throw new NullArgumentException(LocalizedFormats.REAL_FORMAT);
157        }
158
159        this.imaginaryCharacter = imaginaryCharacter;
160        this.imaginaryFormat = imaginaryFormat;
161        this.realFormat = realFormat;
162    }
163
164    /**
165     * Get the set of locales for which complex formats are available.
166     * <p>This is the same set as the {@link NumberFormat} set.</p>
167     * @return available complex format locales.
168     */
169    public static Locale[] getAvailableLocales() {
170        return NumberFormat.getAvailableLocales();
171    }
172
173    /**
174     * This method calls {@link #format(Object,StringBuffer,FieldPosition)}.
175     *
176     * @param c Complex object to format.
177     * @return A formatted number in the form "Re(c) + Im(c)i".
178     */
179    public String format(Complex c) {
180        return format(c, new StringBuffer(), new FieldPosition(0)).toString();
181    }
182
183    /**
184     * This method calls {@link #format(Object,StringBuffer,FieldPosition)}.
185     *
186     * @param c Double object to format.
187     * @return A formatted number.
188     */
189    public String format(Double c) {
190        return format(new Complex(c, 0), new StringBuffer(), new FieldPosition(0)).toString();
191    }
192
193    /**
194     * Formats a {@link Complex} object to produce a string.
195     *
196     * @param complex the object to format.
197     * @param toAppendTo where the text is to be appended
198     * @param pos On input: an alignment field, if desired. On output: the
199     *            offsets of the alignment field
200     * @return the value passed in as toAppendTo.
201     */
202    public StringBuffer format(Complex complex, StringBuffer toAppendTo,
203                               FieldPosition pos) {
204        pos.setBeginIndex(0);
205        pos.setEndIndex(0);
206
207        // format real
208        double re = complex.getReal();
209        CompositeFormat.formatDouble(re, getRealFormat(), toAppendTo, pos);
210
211        // format sign and imaginary
212        double im = complex.getImaginary();
213        StringBuffer imAppendTo;
214        if (im < 0.0) {
215            toAppendTo.append(" - ");
216            imAppendTo = formatImaginary(-im, new StringBuffer(), pos);
217            toAppendTo.append(imAppendTo);
218            toAppendTo.append(getImaginaryCharacter());
219        } else if (im > 0.0 || Double.isNaN(im)) {
220            toAppendTo.append(" + ");
221            imAppendTo = formatImaginary(im, new StringBuffer(), pos);
222            toAppendTo.append(imAppendTo);
223            toAppendTo.append(getImaginaryCharacter());
224        }
225
226        return toAppendTo;
227    }
228
229    /**
230     * Format the absolute value of the imaginary part.
231     *
232     * @param absIm Absolute value of the imaginary part of a complex number.
233     * @param toAppendTo where the text is to be appended.
234     * @param pos On input: an alignment field, if desired. On output: the
235     * offsets of the alignment field.
236     * @return the value passed in as toAppendTo.
237     */
238    private StringBuffer formatImaginary(double absIm,
239                                         StringBuffer toAppendTo,
240                                         FieldPosition pos) {
241        pos.setBeginIndex(0);
242        pos.setEndIndex(0);
243
244        CompositeFormat.formatDouble(absIm, getImaginaryFormat(), toAppendTo, pos);
245        if (toAppendTo.toString().equals("1")) {
246            // Remove the character "1" if it is the only one.
247            toAppendTo.setLength(0);
248        }
249
250        return toAppendTo;
251    }
252
253    /**
254     * Formats a object to produce a string.  {@code obj} must be either a
255     * {@link Complex} object or a {@link Number} object.  Any other type of
256     * object will result in an {@link IllegalArgumentException} being thrown.
257     *
258     * @param obj the object to format.
259     * @param toAppendTo where the text is to be appended
260     * @param pos On input: an alignment field, if desired. On output: the
261     *            offsets of the alignment field
262     * @return the value passed in as toAppendTo.
263     * @see java.text.Format#format(java.lang.Object, java.lang.StringBuffer, java.text.FieldPosition)
264     * @throws MathIllegalArgumentException is {@code obj} is not a valid type.
265     */
266    public StringBuffer format(Object obj, StringBuffer toAppendTo,
267                               FieldPosition pos)
268        throws MathIllegalArgumentException {
269
270        StringBuffer ret = null;
271
272        if (obj instanceof Complex) {
273            ret = format( (Complex)obj, toAppendTo, pos);
274        } else if (obj instanceof Number) {
275            ret = format(new Complex(((Number)obj).doubleValue(), 0.0),
276                         toAppendTo, pos);
277        } else {
278            throw new MathIllegalArgumentException(LocalizedFormats.CANNOT_FORMAT_INSTANCE_AS_COMPLEX,
279                                                   obj.getClass().getName());
280        }
281
282        return ret;
283    }
284
285    /**
286     * Access the imaginaryCharacter.
287     * @return the imaginaryCharacter.
288     */
289    public String getImaginaryCharacter() {
290        return imaginaryCharacter;
291    }
292
293    /**
294     * Access the imaginaryFormat.
295     * @return the imaginaryFormat.
296     */
297    public NumberFormat getImaginaryFormat() {
298        return imaginaryFormat;
299    }
300
301    /**
302     * Returns the default complex format for the current locale.
303     * @return the default complex format.
304     */
305    public static ComplexFormat getInstance() {
306        return getInstance(Locale.getDefault());
307    }
308
309    /**
310     * Returns the default complex format for the given locale.
311     * @param locale the specific locale used by the format.
312     * @return the complex format specific to the given locale.
313     */
314    public static ComplexFormat getInstance(Locale locale) {
315        NumberFormat f = CompositeFormat.getDefaultNumberFormat(locale);
316        return new ComplexFormat(f);
317    }
318
319    /**
320     * Returns the default complex format for the given locale.
321     * @param locale the specific locale used by the format.
322     * @param imaginaryCharacter Imaginary character.
323     * @return the complex format specific to the given locale.
324     * @throws NullArgumentException if {@code imaginaryCharacter} is
325     * {@code null}.
326     * @throws NoDataException if {@code imaginaryCharacter} is an
327     * empty string.
328     */
329    public static ComplexFormat getInstance(String imaginaryCharacter, Locale locale)
330        throws NullArgumentException, NoDataException {
331        NumberFormat f = CompositeFormat.getDefaultNumberFormat(locale);
332        return new ComplexFormat(imaginaryCharacter, f);
333    }
334
335    /**
336     * Access the realFormat.
337     * @return the realFormat.
338     */
339    public NumberFormat getRealFormat() {
340        return realFormat;
341    }
342
343    /**
344     * Parses a string to produce a {@link Complex} object.
345     *
346     * @param source the string to parse.
347     * @return the parsed {@link Complex} object.
348     * @throws MathParseException if the beginning of the specified string
349     * cannot be parsed.
350     */
351    public Complex parse(String source) throws MathParseException {
352        ParsePosition parsePosition = new ParsePosition(0);
353        Complex result = parse(source, parsePosition);
354        if (parsePosition.getIndex() == 0) {
355            throw new MathParseException(source,
356                                         parsePosition.getErrorIndex(),
357                                         Complex.class);
358        }
359        return result;
360    }
361
362    /**
363     * Parses a string to produce a {@link Complex} object.
364     *
365     * @param source the string to parse
366     * @param pos input/ouput parsing parameter.
367     * @return the parsed {@link Complex} object.
368     */
369    public Complex parse(String source, ParsePosition pos) {
370        int initialIndex = pos.getIndex();
371
372        // parse whitespace
373        CompositeFormat.parseAndIgnoreWhitespace(source, pos);
374
375        // parse real
376        Number re = CompositeFormat.parseNumber(source, getRealFormat(), pos);
377        if (re == null) {
378            // invalid real number
379            // set index back to initial, error index should already be set
380            pos.setIndex(initialIndex);
381            return null;
382        }
383
384        // parse sign
385        int startIndex = pos.getIndex();
386        char c = CompositeFormat.parseNextCharacter(source, pos);
387        int sign = 0;
388        switch (c) {
389        case 0 :
390            // no sign
391            // return real only complex number
392            return new Complex(re.doubleValue(), 0.0);
393        case '-' :
394            sign = -1;
395            break;
396        case '+' :
397            sign = 1;
398            break;
399        default :
400            // invalid sign
401            // set index back to initial, error index should be the last
402            // character examined.
403            pos.setIndex(initialIndex);
404            pos.setErrorIndex(startIndex);
405            return null;
406        }
407
408        // parse whitespace
409        CompositeFormat.parseAndIgnoreWhitespace(source, pos);
410
411        // parse imaginary
412        Number im = CompositeFormat.parseNumber(source, getRealFormat(), pos);
413        if (im == null) {
414            // invalid imaginary number
415            // set index back to initial, error index should already be set
416            pos.setIndex(initialIndex);
417            return null;
418        }
419
420        // parse imaginary character
421        if (!CompositeFormat.parseFixedstring(source, getImaginaryCharacter(), pos)) {
422            return null;
423        }
424
425        return new Complex(re.doubleValue(), im.doubleValue() * sign);
426
427    }
428}