JDK8/Java8源码在线阅读
/*
* Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
/*
* This file is available under and governed by the GNU General Public
* License version 2 only, as published by the Free Software Foundation.
* However, the following notice accompanied the original version of this
* file:
*
* Copyright (c) 2007-2012, Stephen Colebourne & Michael Nascimento Santos
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* * Neither the name of JSR-310 nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package java.time;
import static java.time.temporal.ChronoField.DAY_OF_WEEK;
import static java.time.temporal.ChronoUnit.DAYS;
import java.time.format.DateTimeFormatterBuilder;
import java.time.format.TextStyle;
import java.time.temporal.ChronoField;
import java.time.temporal.Temporal;
import java.time.temporal.TemporalAccessor;
import java.time.temporal.TemporalAdjuster;
import java.time.temporal.TemporalField;
import java.time.temporal.TemporalQueries;
import java.time.temporal.TemporalQuery;
import java.time.temporal.UnsupportedTemporalTypeException;
import java.time.temporal.ValueRange;
import java.time.temporal.WeekFields;
import java.util.Locale;
/**
* A day-of-week, such as 'Tuesday'.
* <p>
* {@code DayOfWeek} is an enum representing the 7 days of the week -
* Monday, Tuesday, Wednesday, Thursday, Friday, Saturday and Sunday.
* <p>
* In addition to the textual enum name, each day-of-week has an {@code int} value.
* The {@code int} value follows the ISO-8601 standard, from 1 (Monday) to 7 (Sunday).
* It is recommended that applications use the enum rather than the {@code int} value
* to ensure code clarity.
* <p>
* This enum provides access to the localized textual form of the day-of-week.
* Some locales also assign different numeric values to the days, declaring
* Sunday to have the value 1, however this class provides no support for this.
* See {@link WeekFields} for localized week-numbering.
* <p>
* <b>Do not use {@code ordinal()} to obtain the numeric representation of {@code DayOfWeek}.
* Use {@code getValue()} instead.</b>
* <p>
* This enum represents a common concept that is found in many calendar systems.
* As such, this enum may be used by any calendar system that has the day-of-week
* concept defined exactly equivalent to the ISO calendar system.
*
* @implSpec
* This is an immutable and thread-safe enum.
*
* @since 1.8
*/
public enum DayOfWeek implements TemporalAccessor, TemporalAdjuster {
/**
* The singleton instance for the day-of-week of Monday.
* This has the numeric value of {@code 1}.
*/
MONDAY,
/**
* The singleton instance for the day-of-week of Tuesday.
* This has the numeric value of {@code 2}.
*/
TUESDAY,
/**
* The singleton instance for the day-of-week of Wednesday.
* This has the numeric value of {@code 3}.
*/
WEDNESDAY,
/**
* The singleton instance for the day-of-week of Thursday.
* This has the numeric value of {@code 4}.
*/
THURSDAY,
/**
* The singleton instance for the day-of-week of Friday.
* This has the numeric value of {@code 5}.
*/
FRIDAY,
/**
* The singleton instance for the day-of-week of Saturday.
* This has the numeric value of {@code 6}.
*/
SATURDAY,
/**
* The singleton instance for the day-of-week of Sunday.
* This has the numeric value of {@code 7}.
*/
SUNDAY;
/**
* Private cache of all the constants.
*/
private static final DayOfWeek[] ENUMS = DayOfWeek.values();
//-----------------------------------------------------------------------
/**
* Obtains an instance of {@code DayOfWeek} from an {@code int} value.
* <p>
* {@code DayOfWeek} is an enum representing the 7 days of the week.
* This factory allows the enum to be obtained from the {@code int} value.
* The {@code int} value follows the ISO-8601 standard, from 1 (Monday) to 7 (Sunday).
*
* @param dayOfWeek the day-of-week to represent, from 1 (Monday) to 7 (Sunday)
* @return the day-of-week singleton, not null
* @throws DateTimeException if the day-of-week is invalid
*/
public static DayOfWeek of(int dayOfWeek) {
if (dayOfWeek < 1 || dayOfWeek > 7) {
throw new DateTimeException("Invalid value for DayOfWeek: " + dayOfWeek);
}
return ENUMS[dayOfWeek - 1];
}
//-----------------------------------------------------------------------
/**
* Obtains an instance of {@code DayOfWeek} from a temporal object.
* <p>
* This obtains a day-of-week based on the specified temporal.
* A {@code TemporalAccessor} represents an arbitrary set of date and time information,
* which this factory converts to an instance of {@code DayOfWeek}.
* <p>
* The conversion extracts the {@link ChronoField#DAY_OF_WEEK DAY_OF_WEEK} field.
* <p>
* This method matches the signature of the functional interface {@link TemporalQuery}
* allowing it to be used as a query via method reference, {@code DayOfWeek::from}.
*
* @param temporal the temporal object to convert, not null
* @return the day-of-week, not null
* @throws DateTimeException if unable to convert to a {@code DayOfWeek}
*/
public static DayOfWeek from(TemporalAccessor temporal) {
if (temporal instanceof DayOfWeek) {
return (DayOfWeek) temporal;
}
try {
return of(temporal.get(DAY_OF_WEEK));
} catch (DateTimeException ex) {
throw new DateTimeException("Unable to obtain DayOfWeek from TemporalAccessor: " +
temporal + " of type " + temporal.getClass().getName(), ex);
}
}
//-----------------------------------------------------------------------
/**
* Gets the day-of-week {@code int} value.
* <p>
* The values are numbered following the ISO-8601 standard, from 1 (Monday) to 7 (Sunday).
* See {@link WeekFields#dayOfWeek} for localized week-numbering.
*
* @return the day-of-week, from 1 (Monday) to 7 (Sunday)
*/
public int getValue() {
return ordinal() + 1;
}
//-----------------------------------------------------------------------
/**
* Gets the textual representation, such as 'Mon' or 'Friday'.
* <p>
* This returns the textual name used to identify the day-of-week,
* suitable for presentation to the user.
* The parameters control the style of the returned text and the locale.
* <p>
* If no textual mapping is found then the {@link #getValue() numeric value} is returned.
*
* @param style the length of the text required, not null
* @param locale the locale to use, not null
* @return the text value of the day-of-week, not null
*/
public String getDisplayName(TextStyle style, Locale locale) {
return new DateTimeFormatterBuilder().appendText(DAY_OF_WEEK, style).toFormatter(locale).format(this);
}
//-----------------------------------------------------------------------
/**
* Checks if the specified field is supported.
* <p>
* This checks if this day-of-week can be queried for the specified field.
* If false, then calling the {@link #range(TemporalField) range} and
* {@link #get(TemporalField) get} methods will throw an exception.
* <p>
* If the field is {@link ChronoField#DAY_OF_WEEK DAY_OF_WEEK} then
* this method returns true.
* All other {@code ChronoField} instances will return false.
* <p>
* If the field is not a {@code ChronoField}, then the result of this method
* is obtained by invoking {@code TemporalField.isSupportedBy(TemporalAccessor)}
* passing {@code this} as the argument.
* Whether the field is supported is determined by the field.
*
* @param field the field to check, null returns false
* @return true if the field is supported on this day-of-week, false if not
*/
@Override
public boolean isSupported(TemporalField field) {
if (field instanceof ChronoField) {
return field == DAY_OF_WEEK;
}
return field != null && field.isSupportedBy(this);
}
/**
* Gets the range of valid values for the specified field.
* <p>
* The range object expresses the minimum and maximum valid values for a field.
* This day-of-week is used to enhance the accuracy of the returned range.
* If it is not possible to return the range, because the field is not supported
* or for some other reason, an exception is thrown.
* <p>
* If the field is {@link ChronoField#DAY_OF_WEEK DAY_OF_WEEK} then the
* range of the day-of-week, from 1 to 7, will be returned.
* All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
* <p>
* If the field is not a {@code ChronoField}, then the result of this method
* is obtained by invoking {@code TemporalField.rangeRefinedBy(TemporalAccessor)}
* passing {@code this} as the argument.
* Whether the range can be obtained is determined by the field.
*
* @param field the field to query the range for, not null
* @return the range of valid values for the field, not null
* @throws DateTimeException if the range for the field cannot be obtained
* @throws UnsupportedTemporalTypeException if the field is not supported
*/
@Override
public ValueRange range(TemporalField field) {
if (field == DAY_OF_WEEK) {
return field.range();
}
return TemporalAccessor.super.range(field);
}
/**
* Gets the value of the specified field from this day-of-week as an {@code int}.
* <p>
* This queries this day-of-week for the value for the specified field.
* The returned value will always be within the valid range of values for the field.
* If it is not possible to return the value, because the field is not supported
* or for some other reason, an exception is thrown.
* <p>
* If the field is {@link ChronoField#DAY_OF_WEEK DAY_OF_WEEK} then the
* value of the day-of-week, from 1 to 7, will be returned.
* All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
* <p>
* If the field is not a {@code ChronoField}, then the result of this method
* is obtained by invoking {@code TemporalField.getFrom(TemporalAccessor)}
* passing {@code this} as the argument. Whether the value can be obtained,
* and what the value represents, is determined by the field.
*
* @param field the field to get, not null
* @return the value for the field, within the valid range of values
* @throws DateTimeException if a value for the field cannot be obtained or
* the value is outside the range of valid values for the field
* @throws UnsupportedTemporalTypeException if the field is not supported or
* the range of values exceeds an {@code int}
* @throws ArithmeticException if numeric overflow occurs
*/
@Override
public int get(TemporalField field) {
if (field == DAY_OF_WEEK) {
return getValue();
}
return TemporalAccessor.super.get(field);
}
/**
* Gets the value of the specified field from this day-of-week as a {@code long}.
* <p>
* This queries this day-of-week for the value for the specified field.
* If it is not possible to return the value, because the field is not supported
* or for some other reason, an exception is thrown.
* <p>
* If the field is {@link ChronoField#DAY_OF_WEEK DAY_OF_WEEK} then the
* value of the day-of-week, from 1 to 7, will be returned.
* All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
* <p>
* If the field is not a {@code ChronoField}, then the result of this method
* is obtained by invoking {@code TemporalField.getFrom(TemporalAccessor)}
* passing {@code this} as the argument. Whether the value can be obtained,
* and what the value represents, is determined by the field.
*
* @param field the field to get, not null
* @return the value for the field
* @throws DateTimeException if a value for the field cannot be obtained
* @throws UnsupportedTemporalTypeException if the field is not supported
* @throws ArithmeticException if numeric overflow occurs
*/
@Override
public long getLong(TemporalField field) {
if (field == DAY_OF_WEEK) {
return getValue();
} else if (field instanceof ChronoField) {
throw new UnsupportedTemporalTypeException("Unsupported field: " + field);
}
return field.getFrom(this);
}
//-----------------------------------------------------------------------
/**
* Returns the day-of-week that is the specified number of days after this one.
* <p>
* The calculation rolls around the end of the week from Sunday to Monday.
* The specified period may be negative.
* <p>
* This instance is immutable and unaffected by this method call.
*
* @param days the days to add, positive or negative
* @return the resulting day-of-week, not null
*/
public DayOfWeek plus(long days) {
int amount = (int) (days % 7);
return ENUMS[(ordinal() + (amount + 7)) % 7];
}
/**
* Returns the day-of-week that is the specified number of days before this one.
* <p>
* The calculation rolls around the start of the year from Monday to Sunday.
* The specified period may be negative.
* <p>
* This instance is immutable and unaffected by this method call.
*
* @param days the days to subtract, positive or negative
* @return the resulting day-of-week, not null
*/
public DayOfWeek minus(long days) {
return plus(-(days % 7));
}
//-----------------------------------------------------------------------
/**
* Queries this day-of-week using the specified query.
* <p>
* This queries this day-of-week using the specified query strategy object.
* The {@code TemporalQuery} object defines the logic to be used to
* obtain the result. Read the documentation of the query to understand
* what the result of this method will be.
* <p>
* The result of this method is obtained by invoking the
* {@link TemporalQuery#queryFrom(TemporalAccessor)} method on the
* specified query passing {@code this} as the argument.
*
* @param <R> the type of the result
* @param query the query to invoke, not null
* @return the query result, null may be returned (defined by the query)
* @throws DateTimeException if unable to query (defined by the query)
* @throws ArithmeticException if numeric overflow occurs (defined by the query)
*/
@SuppressWarnings("unchecked")
@Override
public <R> R query(TemporalQuery<R> query) {
if (query == TemporalQueries.precision()) {
return (R) DAYS;
}
/**代码未完, 请加载全部代码(NowJava.com).**/
关注时代Java
关注时代Java