Custom Query
Description
We can create a custom query in two ways.
- implements the
TemporalQueryinterface - Use method reference as a query.
The method should take a
TemporalAccessorand return an object.
Example
import java.time.DayOfWeek;
import java.time.LocalDate;
import java.time.temporal.ChronoField;
import java.time.temporal.TemporalAccessor;
import java.time.temporal.TemporalQuery;
//from w w w . ja va2 s .c o m
public class Main {
public static void main(String[] args) {
LocalDate ld1 = LocalDate.of(2013, 12,1);
Boolean is = ld1.query(new Monday1Query());
System.out.println(is);
}
}
class Monday1Query implements TemporalQuery<Boolean> {
@Override
public Boolean queryFrom(TemporalAccessor temporal) {
if (temporal.isSupported(ChronoField.DAY_OF_MONTH)
&& temporal.isSupported(ChronoField.DAY_OF_WEEK)) {
int dayOfMonth = temporal.get(ChronoField.DAY_OF_MONTH);
int weekDay = temporal.get(ChronoField.DAY_OF_WEEK);
DayOfWeek dayOfWeek = DayOfWeek.of(weekDay);
if (dayOfMonth == 1 && dayOfWeek == DayOfWeek.MONDAY) {
return Boolean.TRUE;
}
}
return Boolean.FALSE;
}
}
The code above generates the following result.
Example 2
The following code rewrites the code above with method reference.
import java.time.DayOfWeek;
import java.time.LocalDate;
import java.time.temporal.ChronoField;
import java.time.temporal.TemporalAccessor;
//ww w. j a v a 2 s. com
public class Main {
public static void main(String[] args) {
LocalDate ld1 = LocalDate.of(2013, 12, 1);
Boolean is = ld1.query(Main::queryFrom);
System.out.println(is);
}
public static Boolean queryFrom(TemporalAccessor temporal) {
if (temporal.isSupported(ChronoField.DAY_OF_MONTH)
&& temporal.isSupported(ChronoField.DAY_OF_WEEK)) {
int dayOfMonth = temporal.get(ChronoField.DAY_OF_MONTH);
int weekDay = temporal.get(ChronoField.DAY_OF_WEEK);
DayOfWeek dayOfWeek = DayOfWeek.of(weekDay);
if (dayOfMonth == 1 && dayOfWeek == DayOfWeek.MONDAY) {
return Boolean.TRUE;
}
}
return Boolean.FALSE;
}
}
The code above generates the following result.
