AmPm.java
/*
* Copyright (c) 2007-present, Stephen Colebourne & Michael Nascimento Santos
*
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package org.threeten.extra;
import static java.time.temporal.ChronoField.AMPM_OF_DAY;
import static java.time.temporal.ChronoField.HOUR_OF_DAY;
import static java.time.temporal.ChronoUnit.HALF_DAYS;
import java.time.DateTimeException;
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.util.Calendar;
import java.util.Locale;
/**
* A half-day before or after midday, with the values 'AM' and 'PM'.
* <p>
* {@code AmPm} is an enum representing the half-day concepts of AM and PM.
* AM is defined as from 00:00 to 11:59, while PM is defined from 12:00 to 23:59.
* <p>
* All date-time fields have an {@code int} value.
* The {@code int} value follows {@link Calendar}, assigning 0 to AM and 1 to PM.
* It is recommended that applications use the enum rather than the {@code int} value
* to ensure code clarity.
* <p>
* <b>Do not use {@code ordinal()} to obtain the numeric representation of {@code AmPm}.
* 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 AM/PM
* concept defined exactly equivalent to the ISO calendar system.
*
* <h3>Implementation Requirements:</h3>
* This is an immutable and thread-safe enum.
*/
public enum AmPm implements TemporalAccessor, TemporalAdjuster {
/**
* The singleton instance for the morning, AM - ante meridiem.
* This has the numeric value of {@code 0}.
*/
AM,
/**
* The singleton instance for the afternoon, PM - post meridiem.
* This has the numeric value of {@code 1}.
*/
PM;
//-----------------------------------------------------------------------
/**
* Obtains an instance of {@code AmPm} from an {@code int} value.
* <p>
* {@code AmPm} is an enum representing before and after midday.
* This factory allows the enum to be obtained from the {@code int} value.
* The {@code int} value follows {@link Calendar}, assigning 0 to AM and 1 to PM.
*
* @param amPmValue the AM/PM value to represent, from 0 (AM) to 1 (PM)
* @return the AM/PM, not null
* @throws DateTimeException if the am-pm is invalid
*/
public static AmPm of(int amPmValue) {
switch (amPmValue) {
case 0:
return AM;
case 1:
return PM;
default:
throw new DateTimeException("Invalid value for AM/PM: " + amPmValue);
}
}
/**
* Obtains an instance of {@code AmPm} from an hour-of-day.
* <p>
* {@code AmPm} is an enum representing before and after midday.
* This factory allows the enum to be obtained from the hour-of-day value, from 0 to 23.
*
* @param hourOfDay the hour-of-day to extract from, from 0 to 23
* @return the AM/PM, not null
* @throws DateTimeException if the hour-of-day is invalid
*/
public static AmPm ofHour(int hourOfDay) {
HOUR_OF_DAY.checkValidValue(hourOfDay);
return hourOfDay < 12 ? AM : PM;
}
//-----------------------------------------------------------------------
/**
* Obtains an instance of {@code AmPm} from a temporal object.
* <p>
* This obtains an am-pm 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 AmPm}.
* <p>
* The conversion extracts the {@link ChronoField#AMPM_OF_DAY AMPM_OF_DAY} 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 AmPm::from}.
*
* @param temporal the temporal object to convert, not null
* @return the AM/PM, not null
* @throws DateTimeException if unable to convert to a {@code AmPm}
*/
public static AmPm from(TemporalAccessor temporal) {
if (temporal instanceof AmPm) {
return (AmPm) temporal;
}
try {
return of(temporal.get(AMPM_OF_DAY));
} catch (DateTimeException ex) {
throw new DateTimeException("Unable to obtain AmPm from TemporalAccessor: " +
temporal + " of type " + temporal.getClass().getName(), ex);
}
}
//-----------------------------------------------------------------------
/**
* Gets the AM/PM {@code int} value.
* <p>
* The values are numbered following {@link Calendar}, assigning 0 to AM and 1 to PM.
*
* @return the AM/PM value, from 0 (AM) to 1 (PM)
*/
public int getValue() {
return ordinal();
}
//-----------------------------------------------------------------------
/**
* Gets the textual representation, such as 'AM' or 'PM'.
* <p>
* This returns the textual name used to identify the am-pm,
* 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 am-pm, not null
*/
public String getDisplayName(TextStyle style, Locale locale) {
return new DateTimeFormatterBuilder().appendText(AMPM_OF_DAY, style).toFormatter(locale).format(this);
}
//-----------------------------------------------------------------------
/**
* Checks if the specified field is supported.
* <p>
* This checks if this am-pm 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#AMPM_OF_DAY AMPM_OF_DAY} 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 am-pm, false if not
*/
@Override
public boolean isSupported(TemporalField field) {
if (field instanceof ChronoField) {
return field == AMPM_OF_DAY;
}
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 am-pm 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#AMPM_OF_DAY AMPM_OF_DAY} then the
* range of the am-pm, from 0 to 1, 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 == AMPM_OF_DAY) {
return field.range();
} else if (field instanceof ChronoField) {
throw new UnsupportedTemporalTypeException("Unsupported field: " + field);
}
return field.rangeRefinedBy(this);
}
/**
* Gets the value of the specified field from this am-pm as an {@code int}.
* <p>
* This queries this am-pm 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#AMPM_OF_DAY AMPM_OF_DAY} then the
* value of the am-pm, from 0 (AM) to 1 (PM), 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 == AMPM_OF_DAY) {
return getValue();
}
return range(field).checkValidIntValue(getLong(field), field);
}
/**
* Gets the value of the specified field from this am-pm as a {@code long}.
* <p>
* This queries this am-pm 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#AMPM_OF_DAY AMPM_OF_DAY} then the
* value of the am-pm, from 0 (AM) to 1 (PM), 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 == AMPM_OF_DAY) {
return getValue();
} else if (field instanceof ChronoField) {
throw new UnsupportedTemporalTypeException("Unsupported field: " + field);
}
return field.getFrom(this);
}
//-----------------------------------------------------------------------
/**
* Queries this am-pm using the specified query.
* <p>
* This queries this am-pm 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) HALF_DAYS;
}
return TemporalAccessor.super.query(query);
}
/**
* Adjusts the specified temporal object to have this am-pm value.
* <p>
* This returns a temporal object of the same observable type as the input
* with the am-pm changed to be the same as this.
* <p>
* The adjustment is equivalent to using {@link Temporal#with(TemporalField, long)}
* passing {@link ChronoField#AMPM_OF_DAY} as the field.
* Note that this adjusts forwards or backwards within a day.
* <p>
* In most cases, it is clearer to reverse the calling pattern by using
* {@link Temporal#with(TemporalAdjuster)}:
* <pre>
* // these two lines are equivalent, but the second approach is recommended
* temporal = thisAmPm.adjustInto(temporal);
* temporal = temporal.with(thisAmPm);
* </pre>
* <p>
* This instance is immutable and unaffected by this method call.
*
* @param temporal the target object to be adjusted, not null
* @return the adjusted object, not null
* @throws DateTimeException if unable to make the adjustment
* @throws ArithmeticException if numeric overflow occurs
*/
@Override
public Temporal adjustInto(Temporal temporal) {
return temporal.with(AMPM_OF_DAY, getValue());
}
}