com.aliyun.openservices.ons.shaded.commons.lang3.time.CalendarReflection Maven / Gradle / Ivy
/*
* 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 com.aliyun.openservices.ons.shaded.commons.lang3.time;
import java.lang.reflect.Method;
import java.util.Calendar;
import java.util.GregorianCalendar;
import com.aliyun.openservices.ons.shaded.commons.lang3.exception.ExceptionUtils;
/**
* Use reflection to access java 1.7 methods in Calendar. This allows compilation with 1.6 compiler.
*/
class CalendarReflection {
private static final Method IS_WEEK_DATE_SUPPORTED = getCalendarMethod("isWeekDateSupported");
private static final Method GET_WEEK_YEAR = getCalendarMethod("getWeekYear");
private static Method getCalendarMethod(String methodName, Class... argTypes) {
try {
Method m = Calendar.class.getMethod(methodName, argTypes);
return m;
} catch (Exception e) {
return null;
}
}
/**
* Does this calendar instance support week date?
* @param calendar The calendar instance.
* @return false, if runtime is less than java 1.7; otherwise, the result of calendar.isWeekDateSupported().
*/
static boolean isWeekDateSupported(Calendar calendar) {
try {
return IS_WEEK_DATE_SUPPORTED!=null && ((Boolean)IS_WEEK_DATE_SUPPORTED.invoke(calendar)).booleanValue();
} catch (Exception e) {
return ExceptionUtils.rethrow(e);
}
}
/**
* Invoke getWeekYear() method of calendar instance.
*
* If runtime is 1.7 or better and calendar instance support week year,
* return the value from invocation of getWeekYear().
*
* If runtime is less than 1.7, and calendar is an instance of
* GregorianCalendar, return an approximation of the week year.
* (Approximation is good for all years after the Julian to Gregorian
* cutover.)
*
* Otherwise, return the calendar instance year value.
*
* @param calendar The calendar instance.
* @return the week year or year value.
*/
public static int getWeekYear(Calendar calendar) {
try {
if (isWeekDateSupported(calendar)) {
return (Integer) GET_WEEK_YEAR.invoke(calendar);
}
} catch (Exception e) {
return ExceptionUtils. rethrow(e);
}
int year = calendar.get(Calendar.YEAR);
if (IS_WEEK_DATE_SUPPORTED == null && calendar instanceof GregorianCalendar) {
// not perfect, won't work before gregorian cutover
// good enough for most business use.
switch (calendar.get(Calendar.MONTH)) {
case Calendar.JANUARY:
if (calendar.get(Calendar.WEEK_OF_YEAR) >= 52) {
--year;
}
break;
case Calendar.DECEMBER:
if (calendar.get(Calendar.WEEK_OF_YEAR) == 1) {
++year;
}
break;
}
}
return year;
}
}