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