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package com.sun.javafx.scene.control.behavior;

import javafx.scene.control.ScrollBar;
import javafx.scene.control.ScrollPane;
import com.sun.javafx.scene.control.inputmap.InputMap;
import javafx.scene.input.MouseEvent;
import javafx.scene.control.skin.ScrollPaneSkin;

import java.util.Optional;

import static javafx.scene.input.KeyCode.DOWN;
import static javafx.scene.input.KeyCode.LEFT;
import static javafx.scene.input.KeyCode.PAGE_DOWN;
import static javafx.scene.input.KeyCode.PAGE_UP;
import static javafx.scene.input.KeyCode.RIGHT;
import static javafx.scene.input.KeyCode.SPACE;
import static javafx.scene.input.KeyCode.UP;
import static javafx.scene.input.KeyCode.HOME;
import static javafx.scene.input.KeyCode.END;


Behavior for ScrollPane.
TODO: the function variables are a poor way to couple to the rest of
the system. This technique avoids a direct dependency on the skin class.
However, this should really be coupled through the control itself instead
of directly to the skin.
/**
 * Behavior for ScrollPane.
 *
 * TODO: the function variables are a poor way to couple to the rest of
 * the system. This technique avoids a direct dependency on the skin class.
 * However, this should really be coupled through the control itself instead
 * of directly to the skin.
 */
public class ScrollPaneBehavior extends BehaviorBase<ScrollPane> {

    private final InputMap<ScrollPane> inputMap;

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

    public ScrollPaneBehavior(ScrollPane scrollPane) {
        super(scrollPane);

        // create a map for scrollpane-specific mappings (this reuses the default
        // InputMap installed on the control, if it is non-null, allowing us to pick up any user-specified mappings)
        inputMap = createInputMap();

        // scrollpane-specific mappings for key and mouse input
        addDefaultMapping(inputMap,
            new InputMap.KeyMapping(LEFT, e -> rtl(scrollPane, this::horizontalUnitIncrement, this::horizontalUnitDecrement)),
            new InputMap.KeyMapping(RIGHT, e -> rtl(scrollPane, this::horizontalUnitDecrement, this::horizontalUnitIncrement)),

            new InputMap.KeyMapping(UP, e -> verticalUnitDecrement()),
            new InputMap.KeyMapping(DOWN, e -> verticalUnitIncrement()),

            new InputMap.KeyMapping(PAGE_UP, e -> verticalPageDecrement()),
            new InputMap.KeyMapping(PAGE_DOWN, e -> verticalPageIncrement()),
            new InputMap.KeyMapping(SPACE, e -> verticalPageIncrement()),

            new InputMap.KeyMapping(HOME, e -> verticalHome()),
            new InputMap.KeyMapping(END, e -> verticalEnd()),

            new InputMap.MouseMapping(MouseEvent.MOUSE_PRESSED, this::mousePressed)
        );
    }



    
                                                                        *
Functions                                                               *
                                                                        *
/***************************************************************************
     *                                                                         *
     * Functions                                                               *
     *                                                                         *
     **************************************************************************/

    @Override public InputMap<ScrollPane> getInputMap() {
        return inputMap;
    }

    public void horizontalUnitIncrement() {
        getHorizontalScrollBar().ifPresent(ScrollBar::increment);
    }
    public void horizontalUnitDecrement() {
        getHorizontalScrollBar().ifPresent(ScrollBar::decrement);
    }
    public void verticalUnitIncrement() {
        getVerticalScrollBar().ifPresent(ScrollBar::increment);
    }
    void verticalUnitDecrement() {
        getVerticalScrollBar().ifPresent(ScrollBar::decrement);
    }
    void horizontalPageIncrement() {
        getHorizontalScrollBar().ifPresent(ScrollBar::increment);
    }
    void horizontalPageDecrement() {
        getHorizontalScrollBar().ifPresent(ScrollBar::decrement);
    }
    void verticalPageIncrement() {
        getVerticalScrollBar().ifPresent(ScrollBar::increment);
    }
    void verticalPageDecrement() {
        getVerticalScrollBar().ifPresent(ScrollBar::decrement);
    }
    void verticalHome() {
        ScrollPane sp = getNode();
        sp.setHvalue(sp.getHmin());
        sp.setVvalue(sp.getVmin());
    }
    void verticalEnd() {
        ScrollPane sp = getNode();
        sp.setHvalue(sp.getHmax());
        sp.setVvalue(sp.getVmax());
    }

    private Optional<ScrollBar> getVerticalScrollBar() {
        return Optional.ofNullable(((ScrollPaneSkin)getNode().getSkin()).getVerticalScrollBar());
    }

    private Optional<ScrollBar> getHorizontalScrollBar() {
        return Optional.ofNullable(((ScrollPaneSkin)getNode().getSkin()).getHorizontalScrollBar());
    }


    
                                                                        *
Mouse event handling                                                    *
                                                                        *
/***************************************************************************
     *                                                                         *
     * Mouse event handling                                                    *
     *                                                                         *
     **************************************************************************/

    public void mousePressed(MouseEvent e) {
        getNode().requestFocus();
    }
}