| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package org.apache.commons.numbers.fraction; |
| |
| import java.text.FieldPosition; |
| import java.text.NumberFormat; |
| import java.text.ParseException; |
| import java.text.ParsePosition; |
| import java.util.Locale; |
| |
| /** |
| * Formats a Fraction number in proper format or improper format. The number |
| * format for each of the whole number, numerator and, denominator can be |
| * configured. |
| */ |
| public class FractionFormat extends AbstractFormat { |
| |
| /** Serializable version identifier */ |
| private static final long serialVersionUID = 3008655719530972612L; |
| |
| /** |
| * Create an improper formatting instance with the default number format |
| * for the numerator and denominator. |
| */ |
| public FractionFormat() { |
| } |
| |
| /** |
| * Create an improper formatting instance with a custom number format for |
| * both the numerator and denominator. |
| * @param format the custom format for both the numerator and denominator. |
| */ |
| public FractionFormat(final NumberFormat format) { |
| super(format); |
| } |
| |
| /** |
| * Create an improper formatting instance with a custom number format for |
| * the numerator and a custom number format for the denominator. |
| * @param numeratorFormat the custom format for the numerator. |
| * @param denominatorFormat the custom format for the denominator. |
| */ |
| public FractionFormat(final NumberFormat numeratorFormat, |
| final NumberFormat denominatorFormat) { |
| super(numeratorFormat, denominatorFormat); |
| } |
| |
| /** |
| * Get the set of locales for which complex formats are available. This |
| * is the same set as the {@link NumberFormat} set. |
| * @return available complex format locales. |
| */ |
| public static Locale[] getAvailableLocales() { |
| return NumberFormat.getAvailableLocales(); |
| } |
| |
| /** |
| * This static method calls formatFraction() on a default instance of |
| * FractionFormat. |
| * |
| * @param f Fraction object to format |
| * @return a formatted fraction in proper form. |
| */ |
| public static String formatFraction(Fraction f) { |
| return getImproperInstance().format(f); |
| } |
| |
| /** |
| * Returns the default complex format for the current locale. |
| * @return the default complex format. |
| */ |
| public static FractionFormat getImproperInstance() { |
| return getImproperInstance(Locale.getDefault()); |
| } |
| |
| /** |
| * Returns the default complex format for the given locale. |
| * @param locale the specific locale used by the format. |
| * @return the complex format specific to the given locale. |
| */ |
| public static FractionFormat getImproperInstance(final Locale locale) { |
| return new FractionFormat(getDefaultNumberFormat(locale)); |
| } |
| |
| /** |
| * Returns the default complex format for the current locale. |
| * @return the default complex format. |
| */ |
| public static FractionFormat getProperInstance() { |
| return getProperInstance(Locale.getDefault()); |
| } |
| |
| /** |
| * Returns the default complex format for the given locale. |
| * @param locale the specific locale used by the format. |
| * @return the complex format specific to the given locale. |
| */ |
| public static FractionFormat getProperInstance(final Locale locale) { |
| return new ProperFractionFormat(getDefaultNumberFormat(locale)); |
| } |
| |
| /** |
| * Create a default number format. The default number format is based on |
| * {@link NumberFormat#getNumberInstance(java.util.Locale)} with the only |
| * customizing is the maximum number of fraction digits, which is set to 0. |
| * @return the default number format. |
| */ |
| protected static NumberFormat getDefaultNumberFormat() { |
| return getDefaultNumberFormat(Locale.getDefault()); |
| } |
| |
| /** |
| * Formats a {@link Fraction} object to produce a string. The fraction is |
| * output in improper format. |
| * |
| * @param fraction the object to format. |
| * @param toAppendTo where the text is to be appended |
| * @param pos On input: an alignment field, if desired. On output: the |
| * offsets of the alignment field |
| * @return the value passed in as toAppendTo. |
| */ |
| public StringBuffer format(final Fraction fraction, |
| final StringBuffer toAppendTo, final FieldPosition pos) { |
| |
| pos.setBeginIndex(0); |
| pos.setEndIndex(0); |
| |
| getNumeratorFormat().format(fraction.getNumerator(), toAppendTo, pos); |
| toAppendTo.append(" / "); |
| getDenominatorFormat().format(fraction.getDenominator(), toAppendTo, |
| pos); |
| |
| return toAppendTo; |
| } |
| |
| /** |
| * Formats an object and appends the result to a StringBuffer. <code>obj</code> must be either a |
| * {@link Fraction} object or a {@link Number} object. Any other type of |
| * object will result in an {@link IllegalArgumentException} being thrown. |
| * |
| * @param obj the object to format. |
| * @param toAppendTo where the text is to be appended |
| * @param pos On input: an alignment field, if desired. On output: the |
| * offsets of the alignment field |
| * @return the value passed in as toAppendTo. |
| * @see java.text.Format#format(java.lang.Object, java.lang.StringBuffer, java.text.FieldPosition) |
| * @throws ArithmeticException if the number cannot be converted to a fraction |
| * @throws IllegalArgumentException if <code>obj</code> is not a valid type. |
| */ |
| @Override |
| public StringBuffer format(final Object obj, |
| final StringBuffer toAppendTo, |
| final FieldPosition pos) { |
| StringBuffer ret = null; |
| |
| if (obj instanceof Fraction) { |
| ret = format((Fraction) obj, toAppendTo, pos); |
| } else if (obj instanceof Number) { |
| ret = format(new Fraction(((Number) obj).doubleValue()), toAppendTo, pos); |
| } else { |
| throw new IllegalArgumentException( |
| "cannot format given object as a fraction number"); |
| } |
| |
| return ret; |
| } |
| |
| /** |
| * Parses a string to produce a {@link Fraction} object. |
| * @param source the string to parse |
| * @return the parsed {@link Fraction} object. |
| * @exception ParseException if the beginning of the specified string |
| * cannot be parsed. |
| */ |
| @Override |
| public Fraction parse(final String source) throws ParseException { |
| final ParsePosition parsePosition = new ParsePosition(0); |
| final Fraction result = parse(source, parsePosition); |
| if (parsePosition.getIndex() == 0) { |
| throw new FractionParseException(source, parsePosition.getErrorIndex(), Fraction.class); |
| } |
| return result; |
| } |
| |
| /** |
| * Parses a string to produce a {@link Fraction} object. This method |
| * expects the string to be formatted as an improper fraction. |
| * @param source the string to parse |
| * @param pos input/output parsing parameter. |
| * @return the parsed {@link Fraction} object. |
| */ |
| @Override |
| public Fraction parse(final String source, final ParsePosition pos) { |
| final int initialIndex = pos.getIndex(); |
| |
| // parse whitespace |
| parseAndIgnoreWhitespace(source, pos); |
| |
| // parse numerator |
| final Number num = getNumeratorFormat().parse(source, pos); |
| if (num == null) { |
| // invalid integer number |
| // set index back to initial, error index should already be set |
| // character examined. |
| pos.setIndex(initialIndex); |
| return null; |
| } |
| |
| // parse '/' |
| final int startIndex = pos.getIndex(); |
| final char c = parseNextCharacter(source, pos); |
| switch (c) { |
| case 0 : |
| // no '/' |
| // return num as a fraction |
| return new Fraction(num.intValue(), 1); |
| case '/' : |
| // found '/', continue parsing denominator |
| break; |
| default : |
| // invalid '/' |
| // set index back to initial, error index should be the last |
| // character examined. |
| pos.setIndex(initialIndex); |
| pos.setErrorIndex(startIndex); |
| return null; |
| } |
| |
| // parse whitespace |
| parseAndIgnoreWhitespace(source, pos); |
| |
| // parse denominator |
| final Number den = getDenominatorFormat().parse(source, pos); |
| if (den == null) { |
| // invalid integer number |
| // set index back to initial, error index should already be set |
| // character examined. |
| pos.setIndex(initialIndex); |
| return null; |
| } |
| |
| return new Fraction(num.intValue(), den.intValue()); |
| } |
| |
| } |