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.math3.fraction; 19 20 import java.io.Serializable; 21 import java.text.FieldPosition; 22 import java.text.NumberFormat; 23 import java.text.ParsePosition; 24 import java.util.Locale; 25 26 import org.apache.commons.math3.exception.NullArgumentException; 27 import org.apache.commons.math3.exception.util.LocalizedFormats; 28 29 /** 30 * Common part shared by both {@link FractionFormat} and {@link BigFractionFormat}. 31 * @since 2.0 32 */ 33 public abstract class AbstractFormat extends NumberFormat implements Serializable { 34 35 /** Serializable version identifier. */ 36 private static final long serialVersionUID = -6981118387974191891L; 37 38 /** The format used for the denominator. */ 39 private NumberFormat denominatorFormat; 40 41 /** The format used for the numerator. */ 42 private NumberFormat numeratorFormat; 43 44 /** 45 * Create an improper formatting instance with the default number format 46 * for the numerator and denominator. 47 */ AbstractFormat()48 protected AbstractFormat() { 49 this(getDefaultNumberFormat()); 50 } 51 52 /** 53 * Create an improper formatting instance with a custom number format for 54 * both the numerator and denominator. 55 * @param format the custom format for both the numerator and denominator. 56 */ AbstractFormat(final NumberFormat format)57 protected AbstractFormat(final NumberFormat format) { 58 this(format, (NumberFormat) format.clone()); 59 } 60 61 /** 62 * Create an improper formatting instance with a custom number format for 63 * the numerator and a custom number format for the denominator. 64 * @param numeratorFormat the custom format for the numerator. 65 * @param denominatorFormat the custom format for the denominator. 66 */ AbstractFormat(final NumberFormat numeratorFormat, final NumberFormat denominatorFormat)67 protected AbstractFormat(final NumberFormat numeratorFormat, 68 final NumberFormat denominatorFormat) { 69 this.numeratorFormat = numeratorFormat; 70 this.denominatorFormat = denominatorFormat; 71 } 72 73 /** 74 * Create a default number format. The default number format is based on 75 * {@link NumberFormat#getNumberInstance(java.util.Locale)}. The only 76 * customization is the maximum number of BigFraction digits, which is set to 0. 77 * @return the default number format. 78 */ getDefaultNumberFormat()79 protected static NumberFormat getDefaultNumberFormat() { 80 return getDefaultNumberFormat(Locale.getDefault()); 81 } 82 83 /** 84 * Create a default number format. The default number format is based on 85 * {@link NumberFormat#getNumberInstance(java.util.Locale)}. The only 86 * customization is the maximum number of BigFraction digits, which is set to 0. 87 * @param locale the specific locale used by the format. 88 * @return the default number format specific to the given locale. 89 */ getDefaultNumberFormat(final Locale locale)90 protected static NumberFormat getDefaultNumberFormat(final Locale locale) { 91 final NumberFormat nf = NumberFormat.getNumberInstance(locale); 92 nf.setMaximumFractionDigits(0); 93 nf.setParseIntegerOnly(true); 94 return nf; 95 } 96 97 /** 98 * Access the denominator format. 99 * @return the denominator format. 100 */ getDenominatorFormat()101 public NumberFormat getDenominatorFormat() { 102 return denominatorFormat; 103 } 104 105 /** 106 * Access the numerator format. 107 * @return the numerator format. 108 */ getNumeratorFormat()109 public NumberFormat getNumeratorFormat() { 110 return numeratorFormat; 111 } 112 113 /** 114 * Modify the denominator format. 115 * @param format the new denominator format value. 116 * @throws NullArgumentException if {@code format} is {@code null}. 117 */ setDenominatorFormat(final NumberFormat format)118 public void setDenominatorFormat(final NumberFormat format) { 119 if (format == null) { 120 throw new NullArgumentException(LocalizedFormats.DENOMINATOR_FORMAT); 121 } 122 this.denominatorFormat = format; 123 } 124 125 /** 126 * Modify the numerator format. 127 * @param format the new numerator format value. 128 * @throws NullArgumentException if {@code format} is {@code null}. 129 */ setNumeratorFormat(final NumberFormat format)130 public void setNumeratorFormat(final NumberFormat format) { 131 if (format == null) { 132 throw new NullArgumentException(LocalizedFormats.NUMERATOR_FORMAT); 133 } 134 this.numeratorFormat = format; 135 } 136 137 /** 138 * Parses <code>source</code> until a non-whitespace character is found. 139 * @param source the string to parse 140 * @param pos input/output parsing parameter. On output, <code>pos</code> 141 * holds the index of the next non-whitespace character. 142 */ parseAndIgnoreWhitespace(final String source, final ParsePosition pos)143 protected static void parseAndIgnoreWhitespace(final String source, 144 final ParsePosition pos) { 145 parseNextCharacter(source, pos); 146 pos.setIndex(pos.getIndex() - 1); 147 } 148 149 /** 150 * Parses <code>source</code> until a non-whitespace character is found. 151 * @param source the string to parse 152 * @param pos input/output parsing parameter. 153 * @return the first non-whitespace character. 154 */ parseNextCharacter(final String source, final ParsePosition pos)155 protected static char parseNextCharacter(final String source, 156 final ParsePosition pos) { 157 int index = pos.getIndex(); 158 final int n = source.length(); 159 char ret = 0; 160 161 if (index < n) { 162 char c; 163 do { 164 c = source.charAt(index++); 165 } while (Character.isWhitespace(c) && index < n); 166 pos.setIndex(index); 167 168 if (index < n) { 169 ret = c; 170 } 171 } 172 173 return ret; 174 } 175 176 /** 177 * Formats a double value as a fraction and appends the result to a StringBuffer. 178 * 179 * @param value the double value to format 180 * @param buffer StringBuffer to append to 181 * @param position On input: an alignment field, if desired. On output: the 182 * offsets of the alignment field 183 * @return a reference to the appended buffer 184 * @see #format(Object, StringBuffer, FieldPosition) 185 */ 186 @Override format(final double value, final StringBuffer buffer, final FieldPosition position)187 public StringBuffer format(final double value, 188 final StringBuffer buffer, final FieldPosition position) { 189 return format(Double.valueOf(value), buffer, position); 190 } 191 192 193 /** 194 * Formats a long value as a fraction and appends the result to a StringBuffer. 195 * 196 * @param value the long value to format 197 * @param buffer StringBuffer to append to 198 * @param position On input: an alignment field, if desired. On output: the 199 * offsets of the alignment field 200 * @return a reference to the appended buffer 201 * @see #format(Object, StringBuffer, FieldPosition) 202 */ 203 @Override format(final long value, final StringBuffer buffer, final FieldPosition position)204 public StringBuffer format(final long value, 205 final StringBuffer buffer, final FieldPosition position) { 206 return format(Long.valueOf(value), buffer, position); 207 } 208 209 } 210