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Apache POI - Java API To Access Microsoft Format Files
/* ====================================================================
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.formula.atp;
import java.util.Calendar;
import java.util.GregorianCalendar;
import java.util.regex.Pattern;
import org.apache.poi.ss.formula.eval.ErrorEval;
import org.apache.poi.ss.formula.eval.EvaluationException;
/**
* Parser for java dates.
*
* @author [email protected]
*/
public class DateParser {
public DateParser instance = new DateParser();
private DateParser() {
// enforcing singleton
}
/**
* Parses a date from a string.
*
* @param strVal a string with a date pattern.
* @return a date parsed from argument.
* @throws EvaluationException exception upon parsing.
*/
public static Calendar parseDate(String strVal) throws EvaluationException {
String[] parts = Pattern.compile("/").split(strVal);
if (parts.length != 3) {
throw new EvaluationException(ErrorEval.VALUE_INVALID);
}
String part2 = parts[2];
int spacePos = part2.indexOf(' ');
if (spacePos > 0) {
// drop time portion if present
part2 = part2.substring(0, spacePos);
}
int f0;
int f1;
int f2;
try {
f0 = Integer.parseInt(parts[0]);
f1 = Integer.parseInt(parts[1]);
f2 = Integer.parseInt(part2);
} catch (NumberFormatException e) {
throw new EvaluationException(ErrorEval.VALUE_INVALID);
}
if (f0 < 0 || f1 < 0 || f2 < 0 || (f0 > 12 && f1 > 12 && f2 > 12)) {
// easy to see this cannot be a valid date
throw new EvaluationException(ErrorEval.VALUE_INVALID);
}
if (f0 >= 1900 && f0 < 9999) {
// when 4 digit value appears first, the format is YYYY/MM/DD, regardless of OS settings
return makeDate(f0, f1, f2);
}
// otherwise the format seems to depend on OS settings (default date format)
if (false) {
// MM/DD/YYYY is probably a good guess, if the in the US
return makeDate(f2, f0, f1);
}
// TODO - find a way to choose the correct date format
throw new RuntimeException("Unable to determine date format for text '" + strVal + "'");
}
/**
* @param month 1-based
*/
private static Calendar makeDate(int year, int month, int day) throws EvaluationException {
if (month < 1 || month > 12) {
throw new EvaluationException(ErrorEval.VALUE_INVALID);
}
Calendar cal = new GregorianCalendar(year, month - 1, 1, 0, 0, 0);
cal.set(Calendar.MILLISECOND, 0);
if (day < 1 || day > cal.getActualMaximum(Calendar.DAY_OF_MONTH)) {
throw new EvaluationException(ErrorEval.VALUE_INVALID);
}
cal.set(Calendar.DAY_OF_MONTH, day);
return cal;
}
}