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Java Date Time - DayOfWeek.query() Examples

Java Date Time Java Java API 

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Class:

java.time.DayOfWeek

java.lang.Objectjava.lang.Objectjava.lang.Enumjava.lang.Enumjava.lang.ComparableComparablejava.io.SerializableSerializablejava.time.DayOfWeekjava.time.DayOfWeekjava.time.temporal.TemporalAccessorTemporalAccessorjava.time.temporal.TemporalAdjusterTemporalAdjusterLogicBig

Method:

public <R> R query(TemporalQuery<R> query)

Returns the query result R from the specified query (TemporalQuery) object.

TemporalQuery is a functional interface whose method queryFrom(TemporalAccessor) is invoked as a result of the 'query' method call. queryFrom(TemporalAccessor) method is passed with 'this' as the TemporalAccessor instance.


Examples:


This example uses a predefined query from TemporalQueries class. 

package com.logicbig.example.dayofweek;

import java.time.DayOfWeek;
import java.time.temporal.TemporalQueries;
import java.time.temporal.TemporalUnit;

public class QueryExample {
    public static void main (String[] args) {
        DayOfWeek d = DayOfWeek.FRIDAY;
        TemporalUnit u = d.query(TemporalQueries.precision());
        System.out.println(u);
    }
}

Output

Days




This example creates a custom query which finds out if underlying TemporalAccessor object is at weekend. 

package com.logicbig.example.dayofweek;

import java.time.DayOfWeek;
import java.time.LocalDate;
import java.time.Month;
import java.time.YearMonth;
import java.time.temporal.ChronoField;
import java.time.temporal.TemporalQuery;

public class QueryExample2 {
    public static void main (String[] args) {
        DayOfWeek d = LocalDate.of(1990, Month.DECEMBER, 2)
                               .minusYears(1)
                               .getDayOfWeek();
        Boolean b = d.query(getWeekEndQuery());
        System.out.println(b);

        b = DayOfWeek.MONDAY.query(getWeekEndQuery());
        System.out.println(b);

        b = LocalDate.of(200, Month.JULY, 15)
                     .query(getWeekEndQuery());
        System.out.println(b);

        b = YearMonth.of(2005, Month.DECEMBER)
                     .query(getWeekEndQuery());
        System.out.println(b);
    }

    public static TemporalQuery<Boolean> getWeekEndQuery () {
        return temporal -> {
            if (temporal.isSupported(ChronoField.DAY_OF_WEEK)) {
                int i = temporal.get(ChronoField.DAY_OF_WEEK);
                return i > 5;
            }
            return null;
        };
    }
}

Output

true
false
false
null

See Also