1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * https://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18 /*
19 * This is not the original file distributed by the Apache Software Foundation
20 * It has been modified by the Hipparchus project
21 */
22
23 package org.hipparchus.fraction;
24
25 import java.text.FieldPosition;
26 import java.text.NumberFormat;
27 import java.text.ParsePosition;
28 import java.util.Locale;
29
30 import org.hipparchus.exception.LocalizedCoreFormats;
31 import org.hipparchus.exception.MathIllegalArgumentException;
32 import org.hipparchus.exception.MathIllegalStateException;
33
34 /**
35 * Formats a Fraction number in proper format or improper format.
36 * <p>
37 * The number format for each of the whole number, numerator and,
38 * denominator can be configured.
39 */
40 public class FractionFormat extends AbstractFormat {
41
42 /** Serializable version identifier */
43 private static final long serialVersionUID = 20160323L;
44
45 /**
46 * Create an improper formatting instance with the default number format
47 * for the numerator and denominator.
48 */
49 public FractionFormat() {
50 // This constructor is intentionally empty. Nothing special is needed here.
51 }
52
53 /**
54 * Create an improper formatting instance with a custom number format for
55 * both the numerator and denominator.
56 * @param format the custom format for both the numerator and denominator.
57 * @throws org.hipparchus.exception.NullArgumentException if the provided format is null.
58 */
59 public FractionFormat(final NumberFormat format) {
60 super(format);
61 }
62
63 /**
64 * Create an improper formatting instance with a custom number format for
65 * the numerator and a custom number format for the denominator.
66 * @param numeratorFormat the custom format for the numerator.
67 * @param denominatorFormat the custom format for the denominator.
68 * @throws org.hipparchus.exception.NullArgumentException if either provided format is null.
69 */
70 public FractionFormat(final NumberFormat numeratorFormat,
71 final NumberFormat denominatorFormat) {
72 super(numeratorFormat, denominatorFormat);
73 }
74
75 /**
76 * Get the set of locales for which complex formats are available. This
77 * is the same set as the {@link NumberFormat} set.
78 * @return available complex format locales.
79 */
80 public static Locale[] getAvailableLocales() {
81 return NumberFormat.getAvailableLocales();
82 }
83
84 /**
85 * This static method calls formatFraction() on a default instance of
86 * FractionFormat.
87 *
88 * @param f Fraction object to format
89 * @return a formatted fraction in proper form.
90 */
91 public static String formatFraction(Fraction f) {
92 return getImproperInstance().format(f);
93 }
94
95 /**
96 * Returns the default complex format for the current locale.
97 * @return the default complex format.
98 */
99 public static FractionFormat getImproperInstance() {
100 return getImproperInstance(Locale.getDefault());
101 }
102
103 /**
104 * Returns the default complex format for the given locale.
105 * @param locale the specific locale used by the format.
106 * @return the complex format specific to the given locale.
107 */
108 public static FractionFormat getImproperInstance(final Locale locale) {
109 return new FractionFormat(getDefaultNumberFormat(locale));
110 }
111
112 /**
113 * Returns the default complex format for the current locale.
114 * @return the default complex format.
115 */
116 public static FractionFormat getProperInstance() {
117 return getProperInstance(Locale.getDefault());
118 }
119
120 /**
121 * Returns the default complex format for the given locale.
122 * @param locale the specific locale used by the format.
123 * @return the complex format specific to the given locale.
124 */
125 public static FractionFormat getProperInstance(final Locale locale) {
126 return new ProperFractionFormat(getDefaultNumberFormat(locale));
127 }
128
129 /**
130 * Create a default number format. The default number format is based on
131 * {@link NumberFormat#getNumberInstance(java.util.Locale)} with the only
132 * customizing is the maximum number of fraction digits, which is set to 0.
133 * @return the default number format.
134 */
135 protected static NumberFormat getDefaultNumberFormat() {
136 return getDefaultNumberFormat(Locale.getDefault());
137 }
138
139 /**
140 * Formats a {@link Fraction} object to produce a string. The fraction is
141 * output in improper format.
142 *
143 * @param fraction the object to format.
144 * @param toAppendTo where the text is to be appended
145 * @param pos On input: an alignment field, if desired. On output: the
146 * offsets of the alignment field
147 * @return the value passed in as toAppendTo.
148 */
149 public StringBuffer format(final Fraction fraction, // NOPMD - PMD false positive, we cannot have @Override here
150 final StringBuffer toAppendTo, final FieldPosition pos) {
151
152 pos.setBeginIndex(0);
153 pos.setEndIndex(0);
154
155 getNumeratorFormat().format(fraction.getNumerator(), toAppendTo, pos);
156 toAppendTo.append(" / ");
157 getDenominatorFormat().format(fraction.getDenominator(), toAppendTo,
158 pos);
159
160 return toAppendTo;
161 }
162
163 /**
164 * Formats an object and appends the result to a StringBuffer. <code>obj</code> must be either a
165 * {@link Fraction} object or a {@link Number} object. Any other type of
166 * object will result in an {@link IllegalArgumentException} being thrown.
167 *
168 * @param obj the object to format.
169 * @param toAppendTo where the text is to be appended
170 * @param pos On input: an alignment field, if desired. On output: the
171 * offsets of the alignment field
172 * @return the value passed in as toAppendTo.
173 * @see java.text.Format#format(java.lang.Object, java.lang.StringBuffer, java.text.FieldPosition)
174 * @throws MathIllegalStateException if the number cannot be converted to a fraction
175 * @throws MathIllegalArgumentException if <code>obj</code> is not a valid type.
176 */
177 @Override
178 public StringBuffer format(final Object obj,
179 final StringBuffer toAppendTo, final FieldPosition pos)
180 throws MathIllegalArgumentException, MathIllegalStateException {
181
182 if (obj instanceof Fraction) {
183 return format((Fraction) obj, toAppendTo, pos);
184 } else if (obj instanceof Number) {
185 return format(new Fraction(((Number) obj).doubleValue()), toAppendTo, pos);
186 } else {
187 throw new MathIllegalArgumentException(LocalizedCoreFormats.CANNOT_FORMAT_OBJECT_TO_FRACTION);
188 }
189
190 }
191
192 /**
193 * Parses a string to produce a {@link Fraction} object.
194 * @param source the string to parse
195 * @return the parsed {@link Fraction} object.
196 * @exception MathIllegalStateException if the beginning of the specified string
197 * cannot be parsed.
198 */
199 @Override
200 public Fraction parse(final String source) throws MathIllegalStateException {
201 final ParsePosition parsePosition = new ParsePosition(0);
202 final Fraction result = parse(source, parsePosition);
203 if (parsePosition.getIndex() == 0) {
204 throw new MathIllegalStateException(LocalizedCoreFormats.CANNOT_PARSE_AS_TYPE,
205 source, parsePosition.getErrorIndex(), Fraction.class);
206 }
207 return result;
208 }
209
210 /**
211 * Parses a string to produce a {@link Fraction} object. This method
212 * expects the string to be formatted as an improper fraction.
213 * @param source the string to parse
214 * @param pos input/output parsing parameter.
215 * @return the parsed {@link Fraction} object.
216 */
217 @Override
218 public Fraction parse(final String source, final ParsePosition pos) {
219 final int initialIndex = pos.getIndex();
220
221 // parse whitespace
222 parseAndIgnoreWhitespace(source, pos);
223
224 // parse numerator
225 final Number num = getNumeratorFormat().parse(source, pos);
226 if (num == null) {
227 // invalid integer number
228 // set index back to initial, error index should already be set
229 // character examined.
230 pos.setIndex(initialIndex);
231 return null;
232 }
233
234 // parse '/'
235 final int startIndex = pos.getIndex();
236 final char c = parseNextCharacter(source, pos);
237 switch (c) {
238 case 0 :
239 // no '/'
240 // return num as a fraction
241 return new Fraction(num.intValue(), 1);
242 case '/' :
243 // found '/', continue parsing denominator
244 break;
245 default :
246 // invalid '/'
247 // set index back to initial, error index should be the last
248 // character examined.
249 pos.setIndex(initialIndex);
250 pos.setErrorIndex(startIndex);
251 return null;
252 }
253
254 // parse whitespace
255 parseAndIgnoreWhitespace(source, pos);
256
257 // parse denominator
258 final Number den = getDenominatorFormat().parse(source, pos);
259 if (den == null) {
260 // invalid integer number
261 // set index back to initial, error index should already be set
262 // character examined.
263 pos.setIndex(initialIndex);
264 return null;
265 }
266
267 return new Fraction(num.intValue(), den.intValue());
268 }
269
270 }