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package javafx.scene.control;

import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;

import com.sun.javafx.scene.control.skin.resources.ControlResources;
import javafx.application.Platform;
import javafx.beans.property.ReadOnlyObjectProperty;
import javafx.collections.ObservableList;
import javafx.geometry.Pos;
import javafx.scene.control.ButtonBar.ButtonData;
import javafx.scene.layout.GridPane;
import javafx.scene.layout.Priority;
import javafx.scene.layout.Region;

A dialog that shows a list of choices to the user, from which they can pick
one item at most.
Type parameters:
<T> – The type of the items to show to the user, and the type that is returned via Dialog.getResult() when the dialog is dismissed.
See Also:
Dialog
Since:
JavaFX 8u40/**
 * A dialog that shows a list of choices to the user, from which they can pick
 * one item at most.
 *
 * @see Dialog
 * @param <T> The type of the items to show to the user, and the type that is returned
 *            via {@link #getResult()} when the dialog is dismissed.
 * @since JavaFX 8u40
 */
public class ChoiceDialog<T> extends Dialog<T> {

    
Fields
/**************************************************************************
     *
     * Fields
     *
     **************************************************************************/

    private final GridPane grid;
    private final Label label;
    private final ComboBox<T> comboBox;
    private final T defaultChoice;



    /**************************************************************************
     *
     * Constructors
     *
     **************************************************************************/

    
Creates a default, empty instance of ChoiceDialog with no set items and a null default choice. Users of this constructor will subsequently need to call getItems() to specify which items to show to the user. /**
     * Creates a default, empty instance of ChoiceDialog with no set items and a
     * null default choice. Users of this constructor will subsequently need to
     * call {@link #getItems()} to specify which items to show to the user.
     */
    public ChoiceDialog() {
        this((T)null, (T[])null);
    }

    
Creates a new ChoiceDialog instance with the first argument specifying the
default choice that should be shown to the user, and all following arguments
considered a varargs array of all available choices for the user. It is
expected that the defaultChoice be one of the elements in the choices varargs
array. If this is not true, then defaultChoice will be set to null and the
dialog will show with the initial choice set to the first item in the list
of choices.
Params:
defaultChoice – The item to display as the pre-selected choice in the dialog.
       This item must be contained within the choices varargs array.
choices – All possible choices to present to the user./**
     * Creates a new ChoiceDialog instance with the first argument specifying the
     * default choice that should be shown to the user, and all following arguments
     * considered a varargs array of all available choices for the user. It is
     * expected that the defaultChoice be one of the elements in the choices varargs
     * array. If this is not true, then defaultChoice will be set to null and the
     * dialog will show with the initial choice set to the first item in the list
     * of choices.
     *
     * @param defaultChoice The item to display as the pre-selected choice in the dialog.
     *        This item must be contained within the choices varargs array.
     * @param choices All possible choices to present to the user.
     */
    public ChoiceDialog(T defaultChoice,  @SuppressWarnings("unchecked") T... choices) {
        this(defaultChoice,
             choices == null ? Collections.emptyList() : Arrays.asList(choices));
    }

    
Creates a new ChoiceDialog instance with the first argument specifying the
default choice that should be shown to the user, and the second argument
specifying a collection of all available choices for the user. It is
expected that the defaultChoice be one of the elements in the choices
collection. If this is not true, then defaultChoice will be set to null and the
dialog will show with the initial choice set to the first item in the list
of choices.
Params:
defaultChoice – The item to display as the pre-selected choice in the dialog.
       This item must be contained within the choices varargs array.
choices – All possible choices to present to the user./**
     * Creates a new ChoiceDialog instance with the first argument specifying the
     * default choice that should be shown to the user, and the second argument
     * specifying a collection of all available choices for the user. It is
     * expected that the defaultChoice be one of the elements in the choices
     * collection. If this is not true, then defaultChoice will be set to null and the
     * dialog will show with the initial choice set to the first item in the list
     * of choices.
     *
     * @param defaultChoice The item to display as the pre-selected choice in the dialog.
     *        This item must be contained within the choices varargs array.
     * @param choices All possible choices to present to the user.
     */
    public ChoiceDialog(T defaultChoice, Collection<T> choices) {
        final DialogPane dialogPane = getDialogPane();

        // -- grid
        this.grid = new GridPane();
        this.grid.setHgap(10);
        this.grid.setMaxWidth(Double.MAX_VALUE);
        this.grid.setAlignment(Pos.CENTER_LEFT);

        // -- label
        label = DialogPane.createContentLabel(dialogPane.getContentText());
        label.setPrefWidth(Region.USE_COMPUTED_SIZE);
        label.textProperty().bind(dialogPane.contentTextProperty());

        dialogPane.contentTextProperty().addListener(o -> updateGrid());

        setTitle(ControlResources.getString("Dialog.confirm.title"));
        dialogPane.setHeaderText(ControlResources.getString("Dialog.confirm.header"));
        dialogPane.getStyleClass().add("choice-dialog");
        dialogPane.getButtonTypes().addAll(ButtonType.OK, ButtonType.CANCEL);

        final double MIN_WIDTH = 150;

        comboBox = new ComboBox<T>();
        comboBox.setMinWidth(MIN_WIDTH);
        if (choices != null) {
            comboBox.getItems().addAll(choices);
        }
        comboBox.setMaxWidth(Double.MAX_VALUE);
        GridPane.setHgrow(comboBox, Priority.ALWAYS);
        GridPane.setFillWidth(comboBox, true);

        this.defaultChoice = comboBox.getItems().contains(defaultChoice) ? defaultChoice : null;

        if (defaultChoice == null) {
            comboBox.getSelectionModel().selectFirst();
        } else {
            comboBox.getSelectionModel().select(defaultChoice);
        }

        updateGrid();

        setResultConverter((dialogButton) -> {
            ButtonData data = dialogButton == null ? null : dialogButton.getButtonData();
            return data == ButtonData.OK_DONE ? getSelectedItem() : null;
        });
    }



    /**************************************************************************
     *
     * Public API
     *
     **************************************************************************/

    
Returns the currently selected item in the dialog.
Returns:
the currently selected item/**
     * Returns the currently selected item in the dialog.
     * @return the currently selected item
     */
    public final T getSelectedItem() {
        return comboBox.getSelectionModel().getSelectedItem();
    }

    
Returns the property representing the currently selected item in the dialog.
Returns:
the currently selected item property/**
     * Returns the property representing the currently selected item in the dialog.
     * @return the currently selected item property
     */
    public final ReadOnlyObjectProperty<T> selectedItemProperty() {
        return comboBox.getSelectionModel().selectedItemProperty();
    }

    
Sets the currently selected item in the dialog.
Params:
item – The item to select in the dialog./**
     * Sets the currently selected item in the dialog.
     * @param item The item to select in the dialog.
     */
    public final void setSelectedItem(T item) {
        comboBox.getSelectionModel().select(item);
    }

    
Returns the list of all items that will be displayed to users. This list
can be modified by the developer to add, remove, or reorder the items
to present to the user.
Returns:
the list of all items that will be displayed to users/**
     * Returns the list of all items that will be displayed to users. This list
     * can be modified by the developer to add, remove, or reorder the items
     * to present to the user.
     * @return the list of all items that will be displayed to users
     */
    public final ObservableList<T> getItems() {
        return comboBox.getItems();
    }

    
Returns the default choice that was specified in the constructor.
Returns:
the default choice/**
     * Returns the default choice that was specified in the constructor.
     * @return the default choice
     */
    public final T getDefaultChoice() {
        return defaultChoice;
    }



    
Private Implementation
/**************************************************************************
     *
     * Private Implementation
     *
     **************************************************************************/

    private void updateGrid() {
        grid.getChildren().clear();

        grid.add(label, 0, 0);
        grid.add(comboBox, 1, 0);
        getDialogPane().setContent(grid);

        Platform.runLater(() -> comboBox.requestFocus());
    }
}