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- /*
- * 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.poi.ss.usermodel;
-
- import java.math.BigDecimal;
- import java.text.FieldPosition;
- import java.text.Format;
- import java.text.ParsePosition;
- import java.util.regex.Matcher;
- import java.util.regex.Pattern;
-
- import org.apache.logging.log4j.LogManager;
- import org.apache.logging.log4j.Logger;
- import org.apache.poi.ss.format.SimpleFraction;
- import org.apache.poi.ss.formula.eval.NotImplementedException;
-
- /**
- * <p>Format class that handles Excel style fractions, such as "# #/#" and "#/###"</p>
- *
- * <p>As of this writing, this is still not 100% accurate, but it does a reasonable job
- * of trying to mimic Excel's fraction calculations. It does not currently
- * maintain Excel's spacing.</p>
- *
- * <p>This class relies on a method lifted nearly verbatim from org.apache.math.fraction.
- * If further uses for Commons Math are found, we will consider adding it as a dependency.
- * For now, we have in-lined the one method to keep things simple.</p>
- */
-
- @SuppressWarnings("serial")
- public class FractionFormat extends Format {
- private static final Logger LOGGER = LogManager.getLogger(FractionFormat.class);
- private static final Pattern DENOM_FORMAT_PATTERN = Pattern.compile("(?:(#+)|(\\d+))");
-
- //this was chosen to match the earlier limitation of max denom power
- //it can be expanded to get closer to Excel's calculations
- //with custom formats # #/#########
- //but as of this writing, the numerators and denominators
- //with formats of that nature on very small values were quite
- //far from Excel's calculations
- private static final int MAX_DENOM_POW = 4;
-
- //there are two options:
- //a) an exact denominator is specified in the formatString
- //b) the maximum denominator can be calculated from the formatString
- private final int exactDenom;
- private final int maxDenom;
-
- private final String wholePartFormatString;
-
- /**
- * Single parameter ctor
- * @param denomFormatString The format string for the denominator
- */
- public FractionFormat(String wholePartFormatString, String denomFormatString) {
- this.wholePartFormatString = wholePartFormatString;
-
- // initialize exactDenom and maxDenom
- Matcher m = DENOM_FORMAT_PATTERN.matcher(denomFormatString);
- int tmpExact = -1;
- int tmpMax = -1;
- if (m.find()){
- if (m.group(2) != null){
- try{
- tmpExact = Integer.parseInt(m.group(2));
- //if the denom is 0, fall back to the default: tmpExact=100
-
- if (tmpExact == 0){
- tmpExact = -1;
- }
- } catch (NumberFormatException e){
- // should not happen because the pattern already verifies that this is a number,
- // but a number larger than Integer.MAX_VALUE can cause it,
- // so throw an exception if we somehow end up here
- throw new IllegalStateException(e);
- }
- } else if (m.group(1) != null) {
- int len = m.group(1).length();
- len = len > MAX_DENOM_POW ? MAX_DENOM_POW : len;
- tmpMax = (int)Math.pow(10, len);
- } else {
- tmpExact = 100;
- }
- }
- if (tmpExact <= 0 && tmpMax <= 0){
- //use 100 as the default denom if something went horribly wrong
- tmpExact = 100;
- }
- exactDenom = tmpExact;
- maxDenom = tmpMax;
- }
-
- @SuppressWarnings("squid:S2111")
- public String format(Number num) {
-
- final BigDecimal doubleValue = new BigDecimal(num.doubleValue());
-
- final boolean isNeg = doubleValue.compareTo(BigDecimal.ZERO) < 0;
-
- final BigDecimal absValue = doubleValue.abs();
- final BigDecimal wholePart = new BigDecimal(absValue.toBigInteger());
- final BigDecimal decPart = absValue.remainder(BigDecimal.ONE);
-
- if (wholePart.add(decPart).compareTo(BigDecimal.ZERO) == 0) {
- return "0";
- }
-
- // if the absolute value is smaller than 1 over the exact or maxDenom
- // you can stop here and return "0"
- // reciprocal is result of an int devision ... and so it's nearly always 0
- // double reciprocal = 1/Math.max(exactDenom, maxDenom);
- // if (absDoubleValue < reciprocal) {
- // return "0";
- // }
-
- //this is necessary to prevent overflow in the maxDenom calculation
- if (decPart.compareTo(BigDecimal.ZERO) == 0){
-
- StringBuilder sb = new StringBuilder();
- if (isNeg){
- sb.append("-");
- }
- sb.append(wholePart);
- return sb.toString();
- }
-
- final SimpleFraction fract;
- try {
- //this should be the case because of the constructor
- if (exactDenom > 0){
- fract = SimpleFraction.buildFractionExactDenominator(decPart.doubleValue(), exactDenom);
- } else {
- fract = SimpleFraction.buildFractionMaxDenominator(decPart.doubleValue(), maxDenom);
- }
- } catch (RuntimeException e){
- LOGGER.atWarn().withThrowable(e).log("Can't format fraction");
- return Double.toString(doubleValue.doubleValue());
- }
-
- StringBuilder sb = new StringBuilder();
-
- //now format the results
- if (isNeg){
- sb.append("-");
- }
-
- //if whole part has to go into the numerator
- if (wholePartFormatString == null || wholePartFormatString.isEmpty()){
- final int fden = fract.getDenominator();
- final int fnum = fract.getNumerator();
- BigDecimal trueNum = wholePart.multiply(new BigDecimal(fden)).add(new BigDecimal(fnum));
- sb.append(trueNum.toBigInteger()).append("/").append(fden);
- return sb.toString();
- }
-
-
- //short circuit if fraction is 0 or 1
- if (fract.getNumerator() == 0){
- sb.append(wholePart);
- return sb.toString();
- } else if (fract.getNumerator() == fract.getDenominator()){
- sb.append(wholePart.add(BigDecimal.ONE));
- return sb.toString();
- }
- //as mentioned above, this ignores the exact space formatting in Excel
- if (wholePart.compareTo(BigDecimal.ZERO) > 0){
- sb.append(wholePart).append(" ");
- }
- sb.append(fract.getNumerator()).append("/").append(fract.getDenominator());
- return sb.toString();
- }
-
- public StringBuffer format(Object obj, StringBuffer toAppendTo, FieldPosition pos) {
- return toAppendTo.append(format((Number)obj));
- }
-
- public Object parseObject(String source, ParsePosition pos) {
- throw new NotImplementedException("Reverse parsing not supported");
- }
-
- }
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