jidefx.utils

Class LazyLoadUtils

java.lang.Object

jidefx.utils.LazyLoadUtils

public class LazyLoadUtils
extends java.lang.Object

LazyLoadUtils provides an easy way to implement the lazy loading feature in a Combobox or a ChoiceBox. Sometimes it takes a long time to create the ObservableList for the control. By using this LazyLoadUtils, we will create the ObservableList only when the popup is about to show or after a delay, so that it doesn't block the UI thread. The UI will come up without the ObservableList and will be set later.

To use it, simply call one of the install methods. The callback will take care of the creation of the ObservableList.

There are two ways to trigger the callback. The first trigger is when the ComboBox or the ChoiceBox is clicked before the popup content is about to show. The beforeShowing flag will determine if this trigger will be triggered. Default is true. If this trigger is triggered, we will call the callback on the UI thread which means users will have to wait for the callback to finish. We will have to do that because the popup doesn't make sense to show without the ObservableList. The second trigger is triggered after a delay. The delay time is controlled by the delay parameter. When it reaches the specified delay duration, a worker thread will run to call the callback so that it doesn't block the UI. Either trigger can come first but it will be triggered only once. Ideally, when the UI is shown, if user never clicks the ComboBox or the ChoiceBox, the second trigger kicks in and populates the data behind the scene. Not ideally, user clicks on it right away and then he/she has to wait a while. However it is still much better than waiting for the same period of time before the UI showing.

A typical use case is to create a ComboBox that list all the fonts in the system. However the Font.getFamilies call is expensive, especially the system has a lot of fonts. The following code will take care of it.

 ComboBox<String> fontComboBox = new ComboBox<>();
 fontComboBox.setValue("Arial"); // set a default value without setting the Items
 LazyLoadUtils.install(fontComboBox, new Callback<ComboBox<String>, ObservableList<String>>() {
     public ObservableList<String> call(ComboBox<String> comboBox) {
         return FXCollections.observableArrayList(Font.getFamilies());
     }
 });
 

Constructor Summary

Constructors

Constructor and Description
LazyLoadUtils()

Method Summary

Modifier and Type	Method and Description
protected static <T> void	customizeChoiceBox(javafx.scene.control.ChoiceBox<T> choiceBox, javafx.util.Callback<javafx.scene.control.ChoiceBox<T>,javafx.collections.ObservableList<T>> callback, javafx.util.Duration delay, boolean beforeShowing, T initialValue) Customizes the ChoiceBox to call the callback until user clicks on the ChoiceBox or after a delay.
protected static <T> void	customizeComboBox(javafx.scene.control.ComboBox<T> comboBox, javafx.util.Callback<javafx.scene.control.ComboBox<T>,javafx.collections.ObservableList<T>> callback, javafx.util.Duration delay, boolean beforeShowing, T initialValue) Customizes the ComboBox to call the callback until user clicks on the ComboBox or after a delay.
static <T> void	install(javafx.scene.control.ChoiceBox<T> choiceBox, javafx.util.Callback<javafx.scene.control.ChoiceBox<T>,javafx.collections.ObservableList<T>> callback) Customizes the ChoiceBox to call the callback and setItems until user clicks on the ChoiceBox or after a 200 ms delay.
static <T> void	install(javafx.scene.control.ChoiceBox<T> choiceBox, javafx.util.Callback<javafx.scene.control.ChoiceBox<T>,javafx.collections.ObservableList<T>> callback, boolean beforeShowing) Customizes the ChoiceBox to call the callback and setItems until user clicks on the ChoiceBox (if beforeShowing is true) or after a 200ms delay.
static <T> void	install(javafx.scene.control.ChoiceBox<T> choiceBox, javafx.util.Callback<javafx.scene.control.ChoiceBox<T>,javafx.collections.ObservableList<T>> callback, javafx.util.Duration delay) Customizes the ChoiceBox to call the callback and setItems until user clicks on the ChoiceBox or after a delay.
static <T> void	install(javafx.scene.control.ChoiceBox<T> choiceBox, javafx.util.Callback<javafx.scene.control.ChoiceBox<T>,javafx.collections.ObservableList<T>> callback, javafx.util.Duration delay, boolean beforeShowing) Customizes the ChoiceBox to call the callback until user clicks on the ChoiceBox (if beforeShowing is true) or after a delay.
static <T> void	install(javafx.scene.control.ChoiceBox<T> choiceBox, javafx.util.Callback<javafx.scene.control.ChoiceBox<T>,javafx.collections.ObservableList<T>> callback, javafx.util.Duration delay, boolean beforeShowing, T initialValue) Customizes the ChoiceBox to call the callback until user clicks on the ChoiceBox (if beforeShowing is true) or after a delay.
static <T> void	install(javafx.scene.control.ComboBox<T> comboBox, javafx.util.Callback<javafx.scene.control.ComboBox<T>,javafx.collections.ObservableList<T>> callback) Customizes the ComboBox to call the callback and setItems until user clicks on the ComboBox or after a 200 ms delay.
static <T> void	install(javafx.scene.control.ComboBox<T> comboBox, javafx.util.Callback<javafx.scene.control.ComboBox<T>,javafx.collections.ObservableList<T>> callback, boolean beforeShowing) Customizes the ComboBox to call the callback and setItems until user clicks on the ComboBox (if beforeShowing is true) or after a 200ms delay.
static <T> void	install(javafx.scene.control.ComboBox<T> comboBox, javafx.util.Callback<javafx.scene.control.ComboBox<T>,javafx.collections.ObservableList<T>> callback, javafx.util.Duration delay) Customizes the ComboBox to call the callback and setItems until user clicks on the ComboBox or after a delay.
static <T> void	install(javafx.scene.control.ComboBox<T> comboBox, javafx.util.Callback<javafx.scene.control.ComboBox<T>,javafx.collections.ObservableList<T>> callback, javafx.util.Duration delay, boolean beforeShowing) Customizes the ComboBox to call the callback until user clicks on the ComboBox (if beforeShowing is true) or after a delay.
static <T> void	install(javafx.scene.control.ComboBox<T> comboBox, javafx.util.Callback<javafx.scene.control.ComboBox<T>,javafx.collections.ObservableList<T>> callback, javafx.util.Duration delay, boolean beforeShowing, T initialValue) Customizes the ComboBox to call the callback until user clicks on the ComboBox (if beforeShowing is true) or after a delay.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

LazyLoadUtils

public LazyLoadUtils()

Method Detail

install

public static <T> void install(javafx.scene.control.ComboBox<T> comboBox,
                               javafx.util.Callback<javafx.scene.control.ComboBox<T>,javafx.collections.ObservableList<T>> callback)

Customizes the ComboBox to call the callback and setItems until user clicks on the ComboBox or after a 200 ms delay.

Type Parameters:

T - The type of the value that has been selected or otherwise entered in to this ComboBox.

Parameters:

comboBox - the ComboBox.

callback - the callback to create the ObservableList.

install

public static <T> void install(javafx.scene.control.ComboBox<T> comboBox,
                               javafx.util.Callback<javafx.scene.control.ComboBox<T>,javafx.collections.ObservableList<T>> callback,
                               javafx.util.Duration delay)

Customizes the ComboBox to call the callback and setItems until user clicks on the ComboBox or after a delay.

Type Parameters:

T - The type of the value that has been selected or otherwise entered in to this ComboBox.

Parameters:

comboBox - the ComboBox.

callback - the callback to create the ObservableList.

delay - the delay before the callback is called.

install

public static <T> void install(javafx.scene.control.ComboBox<T> comboBox,
                               javafx.util.Callback<javafx.scene.control.ComboBox<T>,javafx.collections.ObservableList<T>> callback,
                               boolean beforeShowing)

Customizes the ComboBox to call the callback and setItems until user clicks on the ComboBox (if beforeShowing is true) or after a 200ms delay.

Type Parameters:

T - The type of the value that has been selected or otherwise entered in to this ComboBox.

Parameters:

comboBox - the ComboBox.

callback - the callback to create the ObservableList.

beforeShowing - whether to trigger the callback before the ComboBox popup is about to show, if the callback

install

public static <T> void install(javafx.scene.control.ComboBox<T> comboBox,
                               javafx.util.Callback<javafx.scene.control.ComboBox<T>,javafx.collections.ObservableList<T>> callback,
                               javafx.util.Duration delay,
                               boolean beforeShowing)

Customizes the ComboBox to call the callback until user clicks on the ComboBox (if beforeShowing is true) or after a delay.

Type Parameters:

T - The type of the value that has been selected or otherwise entered in to this ComboBox.

Parameters:

comboBox - the ComboBox.

callback - the callback to create the ObservableList.

delay - the delay before the callback is called.

beforeShowing - whether to trigger the callback before the ComboBox popup is about to show, if the callback hasn't called yet.

install

public static <T> void install(javafx.scene.control.ComboBox<T> comboBox,
                               javafx.util.Callback<javafx.scene.control.ComboBox<T>,javafx.collections.ObservableList<T>> callback,
                               javafx.util.Duration delay,
                               boolean beforeShowing,
                               T initialValue)

Customizes the ComboBox to call the callback until user clicks on the ComboBox (if beforeShowing is true) or after a delay. It will also set the initialValue to the ComboBox.

Type Parameters:

T - The type of the value that has been selected or otherwise entered in to this ComboBox.

Parameters:

comboBox - the ComboBox.

callback - the callback to create the ObservableList.

delay - the delay before the callback is called.

beforeShowing - whether to trigger the callback before the ComboBox popup is about to show, if the callback hasn't called yet.

initialValue - the initial value. Null if the value has been set on the ComboBox.

customizeComboBox

protected static <T> void customizeComboBox(javafx.scene.control.ComboBox<T> comboBox,
                                            javafx.util.Callback<javafx.scene.control.ComboBox<T>,javafx.collections.ObservableList<T>> callback,
                                            javafx.util.Duration delay,
                                            boolean beforeShowing,
                                            T initialValue)

Customizes the ComboBox to call the callback until user clicks on the ComboBox or after a delay.

Type Parameters:

T - The type of the value that has been selected or otherwise entered in to this ComboBox.

Parameters:

comboBox - the ComboBox.

callback - the callback to create the ObservableList.

delay - the delay before the callback is called.

beforeShowing - whether to trigger the callback before the ComboBox popup is about to show, if the callback hasn't called yet.

initialValue - the initial value. Null if the value has been set on the ComboBox.

install

public static <T> void install(javafx.scene.control.ChoiceBox<T> choiceBox,
                               javafx.util.Callback<javafx.scene.control.ChoiceBox<T>,javafx.collections.ObservableList<T>> callback)

Customizes the ChoiceBox to call the callback and setItems until user clicks on the ChoiceBox or after a 200 ms delay.

Type Parameters:

T - The type of the value that has been selected or otherwise entered in to this ChoiceBox.

Parameters:

choiceBox - the ChoiceBox.

callback - the callback to create the ObservableList.

install

public static <T> void install(javafx.scene.control.ChoiceBox<T> choiceBox,
                               javafx.util.Callback<javafx.scene.control.ChoiceBox<T>,javafx.collections.ObservableList<T>> callback,
                               javafx.util.Duration delay)

Customizes the ChoiceBox to call the callback and setItems until user clicks on the ChoiceBox or after a delay.

Type Parameters:

T - The type of the value that has been selected or otherwise entered in to this ChoiceBox.

Parameters:

choiceBox - the ChoiceBox.

callback - the callback to create the ObservableList.

delay - the delay before the callback is called.

install

public static <T> void install(javafx.scene.control.ChoiceBox<T> choiceBox,
                               javafx.util.Callback<javafx.scene.control.ChoiceBox<T>,javafx.collections.ObservableList<T>> callback,
                               boolean beforeShowing)

Customizes the ChoiceBox to call the callback and setItems until user clicks on the ChoiceBox (if beforeShowing is true) or after a 200ms delay.

Type Parameters:

T - The type of the value that has been selected or otherwise entered in to this ChoiceBox.

Parameters:

choiceBox - the ChoiceBox.

callback - the callback to create the ObservableList.

beforeShowing - whether to trigger the callback before the ChoiceBox popup is about to show, if the callback

install

public static <T> void install(javafx.scene.control.ChoiceBox<T> choiceBox,
                               javafx.util.Callback<javafx.scene.control.ChoiceBox<T>,javafx.collections.ObservableList<T>> callback,
                               javafx.util.Duration delay,
                               boolean beforeShowing)

Customizes the ChoiceBox to call the callback until user clicks on the ChoiceBox (if beforeShowing is true) or after a delay.

Type Parameters:

T - The type of the value that has been selected or otherwise entered in to this ChoiceBox.

Parameters:

choiceBox - the ChoiceBox.

callback - the callback to create the ObservableList.

delay - the delay before the callback is called.

beforeShowing - whether to trigger the callback before the ChoiceBox popup is about to show, if the callback hasn't called yet.

install

public static <T> void install(javafx.scene.control.ChoiceBox<T> choiceBox,
                               javafx.util.Callback<javafx.scene.control.ChoiceBox<T>,javafx.collections.ObservableList<T>> callback,
                               javafx.util.Duration delay,
                               boolean beforeShowing,
                               T initialValue)

Customizes the ChoiceBox to call the callback until user clicks on the ChoiceBox (if beforeShowing is true) or after a delay. It will also set the initialValue to the ChoiceBox.

Type Parameters:

T - The type of the value that has been selected or otherwise entered in to this ChoiceBox.

Parameters:

choiceBox - the ChoiceBox.

callback - the callback to create the ObservableList.

delay - the delay before the callback is called.

beforeShowing - whether to trigger the callback before the ChoiceBox popup is about to show, if the callback hasn't called yet.

initialValue - the initial value. Null if the value has been set on the ChoiceBox.

customizeChoiceBox

protected static <T> void customizeChoiceBox(javafx.scene.control.ChoiceBox<T> choiceBox,
                                             javafx.util.Callback<javafx.scene.control.ChoiceBox<T>,javafx.collections.ObservableList<T>> callback,
                                             javafx.util.Duration delay,
                                             boolean beforeShowing,
                                             T initialValue)

Customizes the ChoiceBox to call the callback until user clicks on the ChoiceBox or after a delay.

Type Parameters:

T - The type of the value that has been selected or otherwise entered in to this ChoiceBox.

Parameters:

choiceBox - the ChoiceBox.

callback - the callback to create the ObservableList.

delay - the delay before the callback is called.

beforeShowing - whether to trigger the callback before the ChoiceBox popup is about to show, if the callback hasn't called yet.

initialValue - the initial value. Null if the value has been set on the ChoiceBox.