Here you can find the source of getFragmentInDays(Calendar calendar, int fragment)
Returns the number of days within the fragment.
| Parameter | Description |
|---|---|
| calendar | the calendar to work with, not null |
| fragment | the Calendar field part of calendar to calculate |
| Parameter | Description |
|---|---|
| IllegalArgumentException | if the date is <code>null</code> or fragment is not supported |
public static long getFragmentInDays(Calendar calendar, int fragment)
//package com.java2s; /*// w ww. j a v a 2 s . c o m * 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. */ import java.util.Calendar; import java.util.Date; public class Main { /** * Number of milliseconds in a standard second. * @since 2.1 */ public static final long MILLIS_PER_SECOND = 1000; /** * Number of milliseconds in a standard minute. * @since 2.1 */ public static final long MILLIS_PER_MINUTE = 60 * MILLIS_PER_SECOND; /** * Number of milliseconds in a standard hour. * @since 2.1 */ public static final long MILLIS_PER_HOUR = 60 * MILLIS_PER_MINUTE; /** * Number of milliseconds in a standard day. * @since 2.1 */ public static final long MILLIS_PER_DAY = 24 * MILLIS_PER_HOUR; /** * <p>Returns the number of days within the * fragment. All datefields greater than the fragment will be ignored.</p> * * <p>Asking the days of any date will only return the number of days * of the current month (resulting in a number between 1 and 31). This * method will retrieve the number of days for any fragment. * For example, if you want to calculate the number of days past this year, * your fragment is Calendar.YEAR. The result will be all days of the * past month(s).</p> * * <p>Valid fragments are: Calendar.YEAR, Calendar.MONTH, both * Calendar.DAY_OF_YEAR and Calendar.DATE, Calendar.HOUR_OF_DAY, * Calendar.MINUTE, Calendar.SECOND and Calendar.MILLISECOND * A fragment less than or equal to a DAY field will return 0.</p> * * <p> * <ul> * <li>January 28, 2008 with Calendar.MONTH as fragment will return 28 * (equivalent to deprecated date.getDay())</li> * <li>February 28, 2008 with Calendar.MONTH as fragment will return 28 * (equivalent to deprecated date.getDay())</li> * <li>January 28, 2008 with Calendar.YEAR as fragment will return 28</li> * <li>February 28, 2008 with Calendar.YEAR as fragment will return 59</li> * <li>January 28, 2008 with Calendar.MILLISECOND as fragment will return 0 * (a millisecond cannot be split in days)</li> * </ul> * </p> * * @param date the date to work with, not null * @param fragment the {@code Calendar} field part of date to calculate * @return number of days within the fragment of date * @throws IllegalArgumentException if the date is <code>null</code> or * fragment is not supported * @since 2.4 */ public static long getFragmentInDays(Date date, int fragment) { return getFragment(date, fragment, Calendar.DAY_OF_YEAR); } /** * <p>Returns the number of days within the * fragment. All datefields greater than the fragment will be ignored.</p> * * <p>Asking the days of any date will only return the number of days * of the current month (resulting in a number between 1 and 31). This * method will retrieve the number of days for any fragment. * For example, if you want to calculate the number of days past this year, * your fragment is Calendar.YEAR. The result will be all days of the * past month(s).</p> * * <p>Valid fragments are: Calendar.YEAR, Calendar.MONTH, both * Calendar.DAY_OF_YEAR and Calendar.DATE, Calendar.HOUR_OF_DAY, * Calendar.MINUTE, Calendar.SECOND and Calendar.MILLISECOND * A fragment less than or equal to a DAY field will return 0.</p> * * <p> * <ul> * <li>January 28, 2008 with Calendar.MONTH as fragment will return 28 * (equivalent to calendar.get(Calendar.DAY_OF_MONTH))</li> * <li>February 28, 2008 with Calendar.MONTH as fragment will return 28 * (equivalent to calendar.get(Calendar.DAY_OF_MONTH))</li> * <li>January 28, 2008 with Calendar.YEAR as fragment will return 28 * (equivalent to calendar.get(Calendar.DAY_OF_YEAR))</li> * <li>February 28, 2008 with Calendar.YEAR as fragment will return 59 * (equivalent to calendar.get(Calendar.DAY_OF_YEAR))</li> * <li>January 28, 2008 with Calendar.MILLISECOND as fragment will return 0 * (a millisecond cannot be split in days)</li> * </ul> * </p> * * @param calendar the calendar to work with, not null * @param fragment the {@code Calendar} field part of calendar to calculate * @return number of days within the fragment of date * @throws IllegalArgumentException if the date is <code>null</code> or * fragment is not supported * @since 2.4 */ public static long getFragmentInDays(Calendar calendar, int fragment) { return getFragment(calendar, fragment, Calendar.DAY_OF_YEAR); } /** * Date-version for fragment-calculation in any unit * * @param date the date to work with, not null * @param fragment the Calendar field part of date to calculate * @param unit the {@code Calendar} field defining the unit * @return number of units within the fragment of the date * @throws IllegalArgumentException if the date is <code>null</code> or * fragment is not supported * @since 2.4 */ private static long getFragment(Date date, int fragment, int unit) { if (date == null) { throw new IllegalArgumentException("The date must not be null"); } Calendar calendar = Calendar.getInstance(); calendar.setTime(date); return getFragment(calendar, fragment, unit); } /** * Calendar-version for fragment-calculation in any unit * * @param calendar the calendar to work with, not null * @param fragment the Calendar field part of calendar to calculate * @param unit the {@code Calendar} field defining the unit * @return number of units within the fragment of the calendar * @throws IllegalArgumentException if the date is <code>null</code> or * fragment is not supported * @since 2.4 */ private static long getFragment(Calendar calendar, int fragment, int unit) { if (calendar == null) { throw new IllegalArgumentException("The date must not be null"); } long millisPerUnit = getMillisPerUnit(unit); long result = 0; // Fragments bigger than a day require a breakdown to days switch (fragment) { case Calendar.YEAR: result += (calendar.get(Calendar.DAY_OF_YEAR) * MILLIS_PER_DAY) / millisPerUnit; break; case Calendar.MONTH: result += (calendar.get(Calendar.DAY_OF_MONTH) * MILLIS_PER_DAY) / millisPerUnit; break; } switch (fragment) { // Number of days already calculated for these cases case Calendar.YEAR: case Calendar.MONTH: // The rest of the valid cases case Calendar.DAY_OF_YEAR: case Calendar.DATE: result += (calendar.get(Calendar.HOUR_OF_DAY) * MILLIS_PER_HOUR) / millisPerUnit; //$FALL-THROUGH$ case Calendar.HOUR_OF_DAY: result += (calendar.get(Calendar.MINUTE) * MILLIS_PER_MINUTE) / millisPerUnit; //$FALL-THROUGH$ case Calendar.MINUTE: result += (calendar.get(Calendar.SECOND) * MILLIS_PER_SECOND) / millisPerUnit; //$FALL-THROUGH$ case Calendar.SECOND: result += (calendar.get(Calendar.MILLISECOND) * 1) / millisPerUnit; break; case Calendar.MILLISECOND: break;//never useful default: throw new IllegalArgumentException("The fragment " + fragment + " is not supported"); } return result; } /** * Returns the number of milliseconds of a {@code Calendar} field, if this is a constant value. * This handles millisecond, second, minute, hour and day (even though days can very in length). * * @param unit a {@code Calendar} field constant which is a valid unit for a fragment * @return the number of milliseconds in the field * @throws IllegalArgumentException if date can't be represented in milliseconds * @since 2.4 */ private static long getMillisPerUnit(int unit) { long result = Long.MAX_VALUE; switch (unit) { case Calendar.DAY_OF_YEAR: case Calendar.DATE: result = MILLIS_PER_DAY; break; case Calendar.HOUR_OF_DAY: result = MILLIS_PER_HOUR; break; case Calendar.MINUTE: result = MILLIS_PER_MINUTE; break; case Calendar.SECOND: result = MILLIS_PER_SECOND; break; case Calendar.MILLISECOND: result = 1; break; default: throw new IllegalArgumentException("The unit " + unit + " cannot be represented is milleseconds"); } return result; } }