| /* |
| * 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.ParsePosition; |
| |
| /** |
| * Formats a Fraction number in proper format. The number format for each of |
| * the whole number, numerator and, denominator can be configured. |
| * <p> |
| * Minus signs are only allowed in the whole number part - i.e., |
| * "-3 1/2" is legitimate and denotes -7/2, but "-3 -1/2" is invalid and |
| * will result in a <code>ParseException</code>.</p> |
| */ |
| public class ProperFractionFormat extends FractionFormat { |
| |
| /** Serializable version identifier */ |
| private static final long serialVersionUID = 760934726031766749L; |
| |
| /** The format used for the whole number. */ |
| private NumberFormat wholeFormat; |
| |
| /** |
| * Create a proper formatting instance with the default number format for |
| * the whole, numerator, and denominator. |
| */ |
| public ProperFractionFormat() { |
| this(getDefaultNumberFormat()); |
| } |
| |
| /** |
| * Create a proper formatting instance with a custom number format for the |
| * whole, numerator, and denominator. |
| * @param format the custom format for the whole, numerator, and |
| * denominator. |
| */ |
| public ProperFractionFormat(NumberFormat format) { |
| this(format, (NumberFormat)format.clone(), (NumberFormat)format.clone()); |
| } |
| |
| /** |
| * Create a proper formatting instance with a custom number format for each |
| * of the whole, numerator, and denominator. |
| * @param wholeFormat the custom format for the whole. |
| * @param numeratorFormat the custom format for the numerator. |
| * @param denominatorFormat the custom format for the denominator. |
| */ |
| public ProperFractionFormat(NumberFormat wholeFormat, |
| NumberFormat numeratorFormat, |
| NumberFormat denominatorFormat) |
| { |
| super(numeratorFormat, denominatorFormat); |
| setWholeFormat(wholeFormat); |
| } |
| |
| /** |
| * Formats a {@link Fraction} object to produce a string. The fraction |
| * is output in proper 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. |
| */ |
| @Override |
| public StringBuffer format(Fraction fraction, StringBuffer toAppendTo, |
| FieldPosition pos) { |
| |
| pos.setBeginIndex(0); |
| pos.setEndIndex(0); |
| |
| int num = fraction.getNumerator(); |
| int den = fraction.getDenominator(); |
| int whole = num / den; |
| num %= den; |
| |
| if (whole != 0) { |
| getWholeFormat().format(whole, toAppendTo, pos); |
| toAppendTo.append(' '); |
| num = Math.abs(num); |
| } |
| getNumeratorFormat().format(num, toAppendTo, pos); |
| toAppendTo.append(" / "); |
| getDenominatorFormat().format(den, toAppendTo, pos); |
| |
| return toAppendTo; |
| } |
| |
| /** |
| * Access the whole format. |
| * @return the whole format. |
| */ |
| public NumberFormat getWholeFormat() { |
| return wholeFormat; |
| } |
| |
| /** |
| * Parses a string to produce a {@link Fraction} object. This method |
| * expects the string to be formatted as a proper fraction. |
| * <p> |
| * Minus signs are only allowed in the whole number part - i.e., |
| * "-3 1/2" is legitimate and denotes -7/2, but "-3 -1/2" is invalid and |
| * will result in a <code>ParseException</code>.</p> |
| * |
| * @param source the string to parse |
| * @param pos input/ouput parsing parameter. |
| * @return the parsed {@link Fraction} object. |
| */ |
| @Override |
| public Fraction parse(String source, ParsePosition pos) { |
| // try to parse improper fraction |
| Fraction ret = super.parse(source, pos); |
| if (ret != null) { |
| return ret; |
| } |
| |
| int initialIndex = pos.getIndex(); |
| |
| // parse whitespace |
| parseAndIgnoreWhitespace(source, pos); |
| |
| // parse whole |
| Number whole = getWholeFormat().parse(source, pos); |
| if (whole == null) { |
| // invalid integer number |
| // set index back to initial, error index should already be set |
| // character examined. |
| pos.setIndex(initialIndex); |
| return null; |
| } |
| |
| // parse whitespace |
| parseAndIgnoreWhitespace(source, pos); |
| |
| // parse numerator |
| 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; |
| } |
| |
| if (num.intValue() < 0) { |
| // minus signs should be leading, invalid expression |
| pos.setIndex(initialIndex); |
| return null; |
| } |
| |
| // parse '/' |
| int startIndex = pos.getIndex(); |
| 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 |
| 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; |
| } |
| |
| if (den.intValue() < 0) { |
| // minus signs must be leading, invalid |
| pos.setIndex(initialIndex); |
| return null; |
| } |
| |
| int w = whole.intValue(); |
| int sign = w >= 0 ? 1 : -1; |
| int n = num.intValue(); |
| int d = den.intValue(); |
| return new Fraction(((Math.abs(w) * d) + n) * sign, d); |
| } |
| |
| /** |
| * Modify the whole format. |
| * @param format The new whole format value. |
| * @throws NullPointerException if {@code format} is {@code null}. |
| */ |
| public void setWholeFormat(NumberFormat format) { |
| if (format == null) { |
| throw new NullPointerException("whole format"); |
| } |
| this.wholeFormat = format; |
| } |
| } |