Raymond | dee0849 | 2015-04-02 10:43:13 -0700 | [diff] [blame] | 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 | * http://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 | package org.apache.commons.math.fraction; |
| 19 | |
| 20 | import java.io.Serializable; |
| 21 | import java.math.BigInteger; |
| 22 | import java.text.FieldPosition; |
| 23 | import java.text.NumberFormat; |
| 24 | import java.text.ParseException; |
| 25 | import java.text.ParsePosition; |
| 26 | import java.util.Locale; |
| 27 | |
| 28 | import org.apache.commons.math.MathRuntimeException; |
| 29 | import org.apache.commons.math.exception.util.LocalizedFormats; |
| 30 | |
| 31 | /** |
| 32 | * Formats a BigFraction number in proper format or improper format. |
| 33 | * <p> |
| 34 | * The number format for each of the whole number, numerator and, |
| 35 | * denominator can be configured. |
| 36 | * </p> |
| 37 | * |
| 38 | * @since 2.0 |
| 39 | * @version $Revision: 983921 $ $Date: 2010-08-10 12:46:06 +0200 (mar. 10 août 2010) $ |
| 40 | */ |
| 41 | public class BigFractionFormat extends AbstractFormat implements Serializable { |
| 42 | |
| 43 | /** Serializable version identifier */ |
| 44 | private static final long serialVersionUID = -2932167925527338976L; |
| 45 | |
| 46 | /** |
| 47 | * Create an improper formatting instance with the default number format |
| 48 | * for the numerator and denominator. |
| 49 | */ |
| 50 | public BigFractionFormat() { |
| 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 | */ |
| 58 | public BigFractionFormat(final NumberFormat format) { |
| 59 | super(format); |
| 60 | } |
| 61 | |
| 62 | /** |
| 63 | * Create an improper formatting instance with a custom number format for |
| 64 | * the numerator and a custom number format for the denominator. |
| 65 | * @param numeratorFormat the custom format for the numerator. |
| 66 | * @param denominatorFormat the custom format for the denominator. |
| 67 | */ |
| 68 | public BigFractionFormat(final NumberFormat numeratorFormat, |
| 69 | final NumberFormat denominatorFormat) { |
| 70 | super(numeratorFormat, denominatorFormat); |
| 71 | } |
| 72 | |
| 73 | /** |
| 74 | * Get the set of locales for which complex formats are available. This |
| 75 | * is the same set as the {@link NumberFormat} set. |
| 76 | * @return available complex format locales. |
| 77 | */ |
| 78 | public static Locale[] getAvailableLocales() { |
| 79 | return NumberFormat.getAvailableLocales(); |
| 80 | } |
| 81 | |
| 82 | /** |
| 83 | * This static method calls formatBigFraction() on a default instance of |
| 84 | * BigFractionFormat. |
| 85 | * |
| 86 | * @param f BigFraction object to format |
| 87 | * @return A formatted BigFraction in proper form. |
| 88 | */ |
| 89 | public static String formatBigFraction(final BigFraction f) { |
| 90 | return getImproperInstance().format(f); |
| 91 | } |
| 92 | |
| 93 | /** |
| 94 | * Returns the default complex format for the current locale. |
| 95 | * @return the default complex format. |
| 96 | */ |
| 97 | public static BigFractionFormat getImproperInstance() { |
| 98 | return getImproperInstance(Locale.getDefault()); |
| 99 | } |
| 100 | |
| 101 | /** |
| 102 | * Returns the default complex format for the given locale. |
| 103 | * @param locale the specific locale used by the format. |
| 104 | * @return the complex format specific to the given locale. |
| 105 | */ |
| 106 | public static BigFractionFormat getImproperInstance(final Locale locale) { |
| 107 | return new BigFractionFormat(getDefaultNumberFormat(locale)); |
| 108 | } |
| 109 | |
| 110 | /** |
| 111 | * Returns the default complex format for the current locale. |
| 112 | * @return the default complex format. |
| 113 | */ |
| 114 | public static BigFractionFormat getProperInstance() { |
| 115 | return getProperInstance(Locale.getDefault()); |
| 116 | } |
| 117 | |
| 118 | /** |
| 119 | * Returns the default complex format for the given locale. |
| 120 | * @param locale the specific locale used by the format. |
| 121 | * @return the complex format specific to the given locale. |
| 122 | */ |
| 123 | public static BigFractionFormat getProperInstance(final Locale locale) { |
| 124 | return new ProperBigFractionFormat(getDefaultNumberFormat(locale)); |
| 125 | } |
| 126 | |
| 127 | /** |
| 128 | * Formats a {@link BigFraction} object to produce a string. The BigFraction is |
| 129 | * output in improper format. |
| 130 | * |
| 131 | * @param BigFraction the object to format. |
| 132 | * @param toAppendTo where the text is to be appended |
| 133 | * @param pos On input: an alignment field, if desired. On output: the |
| 134 | * offsets of the alignment field |
| 135 | * @return the value passed in as toAppendTo. |
| 136 | */ |
| 137 | public StringBuffer format(final BigFraction BigFraction, |
| 138 | final StringBuffer toAppendTo, final FieldPosition pos) { |
| 139 | |
| 140 | pos.setBeginIndex(0); |
| 141 | pos.setEndIndex(0); |
| 142 | |
| 143 | getNumeratorFormat().format(BigFraction.getNumerator(), toAppendTo, pos); |
| 144 | toAppendTo.append(" / "); |
| 145 | getDenominatorFormat().format(BigFraction.getDenominator(), toAppendTo, pos); |
| 146 | |
| 147 | return toAppendTo; |
| 148 | } |
| 149 | |
| 150 | /** |
| 151 | * Formats an object and appends the result to a StringBuffer. |
| 152 | * <code>obj</code> must be either a {@link BigFraction} object or a |
| 153 | * {@link BigInteger} object or a {@link Number} object. Any other type of |
| 154 | * object will result in an {@link IllegalArgumentException} being thrown. |
| 155 | * |
| 156 | * @param obj the object to format. |
| 157 | * @param toAppendTo where the text is to be appended |
| 158 | * @param pos On input: an alignment field, if desired. On output: the |
| 159 | * offsets of the alignment field |
| 160 | * @return the value passed in as toAppendTo. |
| 161 | * @see java.text.Format#format(java.lang.Object, java.lang.StringBuffer, java.text.FieldPosition) |
| 162 | * @throws IllegalArgumentException is <code>obj</code> is not a valid type. |
| 163 | */ |
| 164 | @Override |
| 165 | public StringBuffer format(final Object obj, |
| 166 | final StringBuffer toAppendTo, final FieldPosition pos) { |
| 167 | |
| 168 | final StringBuffer ret; |
| 169 | if (obj instanceof BigFraction) { |
| 170 | ret = format((BigFraction) obj, toAppendTo, pos); |
| 171 | } else if (obj instanceof BigInteger) { |
| 172 | ret = format(new BigFraction((BigInteger) obj), toAppendTo, pos); |
| 173 | } else if (obj instanceof Number) { |
| 174 | ret = format(new BigFraction(((Number) obj).doubleValue()), |
| 175 | toAppendTo, pos); |
| 176 | } else { |
| 177 | throw MathRuntimeException.createIllegalArgumentException( |
| 178 | LocalizedFormats.CANNOT_FORMAT_OBJECT_TO_FRACTION); |
| 179 | } |
| 180 | |
| 181 | return ret; |
| 182 | } |
| 183 | |
| 184 | /** |
| 185 | * Parses a string to produce a {@link BigFraction} object. |
| 186 | * @param source the string to parse |
| 187 | * @return the parsed {@link BigFraction} object. |
| 188 | * @exception ParseException if the beginning of the specified string |
| 189 | * cannot be parsed. |
| 190 | */ |
| 191 | @Override |
| 192 | public BigFraction parse(final String source) throws ParseException { |
| 193 | final ParsePosition parsePosition = new ParsePosition(0); |
| 194 | final BigFraction result = parse(source, parsePosition); |
| 195 | if (parsePosition.getIndex() == 0) { |
| 196 | throw MathRuntimeException.createParseException( |
| 197 | parsePosition.getErrorIndex(), |
| 198 | LocalizedFormats.UNPARSEABLE_FRACTION_NUMBER, source); |
| 199 | } |
| 200 | return result; |
| 201 | } |
| 202 | |
| 203 | /** |
| 204 | * Parses a string to produce a {@link BigFraction} object. |
| 205 | * This method expects the string to be formatted as an improper BigFraction. |
| 206 | * @param source the string to parse |
| 207 | * @param pos input/ouput parsing parameter. |
| 208 | * @return the parsed {@link BigFraction} object. |
| 209 | */ |
| 210 | @Override |
| 211 | public BigFraction parse(final String source, final ParsePosition pos) { |
| 212 | final int initialIndex = pos.getIndex(); |
| 213 | |
| 214 | // parse whitespace |
| 215 | parseAndIgnoreWhitespace(source, pos); |
| 216 | |
| 217 | // parse numerator |
| 218 | final BigInteger num = parseNextBigInteger(source, pos); |
| 219 | if (num == null) { |
| 220 | // invalid integer number |
| 221 | // set index back to initial, error index should already be set |
| 222 | // character examined. |
| 223 | pos.setIndex(initialIndex); |
| 224 | return null; |
| 225 | } |
| 226 | |
| 227 | // parse '/' |
| 228 | final int startIndex = pos.getIndex(); |
| 229 | final char c = parseNextCharacter(source, pos); |
| 230 | switch (c) { |
| 231 | case 0 : |
| 232 | // no '/' |
| 233 | // return num as a BigFraction |
| 234 | return new BigFraction(num); |
| 235 | case '/' : |
| 236 | // found '/', continue parsing denominator |
| 237 | break; |
| 238 | default : |
| 239 | // invalid '/' |
| 240 | // set index back to initial, error index should be the last |
| 241 | // character examined. |
| 242 | pos.setIndex(initialIndex); |
| 243 | pos.setErrorIndex(startIndex); |
| 244 | return null; |
| 245 | } |
| 246 | |
| 247 | // parse whitespace |
| 248 | parseAndIgnoreWhitespace(source, pos); |
| 249 | |
| 250 | // parse denominator |
| 251 | final BigInteger den = parseNextBigInteger(source, pos); |
| 252 | if (den == null) { |
| 253 | // invalid integer number |
| 254 | // set index back to initial, error index should already be set |
| 255 | // character examined. |
| 256 | pos.setIndex(initialIndex); |
| 257 | return null; |
| 258 | } |
| 259 | |
| 260 | return new BigFraction(num, den); |
| 261 | } |
| 262 | |
| 263 | /** |
| 264 | * Parses a string to produce a <code>BigInteger</code>. |
| 265 | * @param source the string to parse |
| 266 | * @param pos input/ouput parsing parameter. |
| 267 | * @return a parsed <code>BigInteger</code> or null if string does not |
| 268 | * contain a BigInteger at the specified position |
| 269 | */ |
| 270 | protected BigInteger parseNextBigInteger(final String source, |
| 271 | final ParsePosition pos) { |
| 272 | |
| 273 | final int start = pos.getIndex(); |
| 274 | int end = (source.charAt(start) == '-') ? (start + 1) : start; |
| 275 | while((end < source.length()) && |
| 276 | Character.isDigit(source.charAt(end))) { |
| 277 | ++end; |
| 278 | } |
| 279 | |
| 280 | try { |
| 281 | BigInteger n = new BigInteger(source.substring(start, end)); |
| 282 | pos.setIndex(end); |
| 283 | return n; |
| 284 | } catch (NumberFormatException nfe) { |
| 285 | pos.setErrorIndex(start); |
| 286 | return null; |
| 287 | } |
| 288 | |
| 289 | } |
| 290 | |
| 291 | } |