How do I change a property of all DatePickers in my project? (javaFX)

Question

I have multiple DatePickers in my project and I want to make it so that the user cannot edit the text field and so they can't select a date before todays date on all of them.
I know how to do this to individual DatePickers but I want a way to apply this to all of them.
Here's the code I would use for them individually:

DatePicker datePicker = new DatePicker();
datePicker.getEditor().setDisable(true);
datePicker.getEditor().setOpacity(1);
datePicker.setDayCellFactory(param -> new DateCell() {
                @Override
                public void updateItem(LocalDate date, boolean empty) {
                    super.updateItem(date, empty);
                    setDisable(empty || date.compareTo(LocalDate.now()) < 0 );
                }
            });

Edit: As James_D commented I could just put these commands in a method which is the solution I used. Using a builder for this is also interesting, thanks for the detailed answer.

Answer 1

Use some kind of creational pattern, e.g. a builder pattern.

Create an implementation of Builder<DatePicker>:

import java.time.LocalDate;

import javafx.scene.control.DateCell;
import javafx.scene.control.DatePicker;
import javafx.util.Builder;

public class DatePickerBuilder implements Builder<DatePicker>{

    public DatePicker build() {
        DatePicker datePicker = new DatePicker();
        datePicker.getEditor().setDisable(true);
        datePicker.getEditor().setOpacity(1);
        datePicker.setDayCellFactory(param -> new DateCell() {
            @Override
            public void updateItem(LocalDate date, boolean empty) {
                super.updateItem(date, empty);
                setDisable(empty || date.compareTo(LocalDate.now()) < 0 );
            }
        });
        return datePicker ; 

    }
}

If you're creating your DatePickers in Java code, you can simply instantiate a DatePickerBuilder and use it:

private final DatePickerBuilder datePickerBuilder = new DatePickerBuilder();

// ...

// any time you need a `DatePicker` do
DatePicker datePicker = datePickerBuilder.build();

If you're using FXML, you can wrap the DatePickerBuilder in a custom BuilderFactory:

import javafx.fxml.JavaFXBuilderFactory;
import javafx.scene.control.DatePicker;
import javafx.util.Builder;
import javafx.util.BuilderFactory;

public class DatePickerBuilderFactory implements BuilderFactory {

    private final BuilderFactory defaultFactory ;
    private final DatePickerBuilder builder ;
    
    public DatePickerBuilderFactory() {
        defaultFactory = new JavaFXBuilderFactory();
        builder = new DatePickerBuilder();
    }

    @Override
    public Builder<?> getBuilder(Class<?> type) {
        if (type == DatePicker.class) {
            return builder;
        } else return defaultFactory.getBuilder(type) ;
    }
    
    
}

which you can then supply to your FXMLLoader:

    FXMLLoader fxmlLoader = new FXMLLoader(getClass().getResource("path/to/fxml"));
    fxmlLoader.setBuilderFactory(new DatePickerBuilderFactory());
    Parent root = fxmlLoader.load();

Deprecation note:

The individual Builder classes defined in JavaFX version 2.0 were deprecated in version 8.0 due to an implementation error, and removed in version 9 as there was no clean way to fix that error.

However, the BuilderFactory and Builder interfaces are still supported and used by the FXMLLoader, so this code is still supported.