/*
 * Copyright (c) 2010, 2019, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package javafx.scene.control;

import javafx.scene.control.skin.LabelSkin;
import com.sun.javafx.scene.NodeHelper;

import javafx.beans.property.ObjectProperty;
import javafx.beans.property.ObjectPropertyBase;
import javafx.beans.value.ChangeListener;
import javafx.beans.value.WritableValue;
import javafx.css.StyleableProperty;
import javafx.scene.AccessibleRole;
import javafx.scene.Node;

Label is a non-editable text control. A Label is useful for displaying
text that is required to fit within a specific space, and thus may need
to use an ellipsis or truncation to size the string to fit. Labels also are
useful in that they can have mnemonics which, if used, will send focus to
the Control listed as the target of the labelFor property.

Label sets focusTraversable to false.

Example:
Label label = new Label("a label");

Since:
JavaFX 2.0/**
 * Label is a non-editable text control. A Label is useful for displaying
 * text that is required to fit within a specific space, and thus may need
 * to use an ellipsis or truncation to size the string to fit. Labels also are
 * useful in that they can have mnemonics which, if used, will send focus to
 * the Control listed as the target of the <code>labelFor</code> property.
 * <p>
 * Label sets focusTraversable to false.
 * </p>
 *
 * <p>Example:
 * <pre><code>Label label = new Label("a label");</code></pre>
 *
 * <img src="doc-files/Label.png" alt="Image of the Label control">
 *
 * @since JavaFX 2.0
 */
public class Label extends Labeled {

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

    
Creates an empty label
/**
     * Creates an empty label
     */
    public Label() {
        initialize();
    }

    
Creates Label with supplied text.
Params:
text – null text is treated as the empty string/**
     * Creates Label with supplied text.
     * @param text null text is treated as the empty string
     */
    public Label(String text) {
        super(text);
        initialize();
    }

    
Creates a Label with the supplied text and graphic.
Params:
text – null text is treated as the empty string
graphic – a null graphic is acceptable/**
     * Creates a Label with the supplied text and graphic.
     * @param text null text is treated as the empty string
     * @param graphic a null graphic is acceptable
     */
    public Label(String text, Node graphic) {
        super(text, graphic);
        initialize();
    }

    private void initialize() {
        getStyleClass().setAll("label");
        setAccessibleRole(AccessibleRole.TEXT);
        // Labels are not focus traversable, unlike most other UI Controls.
        // focusTraversable is styleable through css. Calling setFocusTraversable
        // makes it look to css like the user set the value and css will not
        // override. Initializing focusTraversable by calling set on the
        // CssMetaData ensures that css will be able to override the value.
        ((StyleableProperty<Boolean>)(WritableValue<Boolean>)focusTraversableProperty()).applyStyle(null, Boolean.FALSE);
    }

    
                                                                        *
Properties                                                              *
                                                                        *
/***************************************************************************
     *                                                                         *
     * Properties                                                              *
     *                                                                         *
     **************************************************************************/

    private ChangeListener<Boolean> mnemonicStateListener = (observable, oldValue, newValue) -> {
        NodeHelper.showMnemonicsProperty(Label.this).setValue(newValue);
    };

    
A Label can act as a label for a different Control or
Node. This is used for Mnemonics and Accelerator parsing.
This allows setting of the target Node.
Returns:
the Node that this label is to be associated with/**
     * A Label can act as a label for a different Control or
     * Node. This is used for Mnemonics and Accelerator parsing.
     * This allows setting of the target Node.
     * @return the Node that this label is to be associated with
     */
    public ObjectProperty<Node> labelForProperty() {
        if (labelFor == null) {
            labelFor = new ObjectPropertyBase<Node>() {
                Node oldValue = null;
                @Override protected void invalidated() {
                    if (oldValue != null) {
                        NodeHelper.getNodeAccessor().setLabeledBy(oldValue, null);
                        NodeHelper.showMnemonicsProperty(oldValue).removeListener(mnemonicStateListener);
                    }
                    final Node node = get();
                    if (node != null) {
                        NodeHelper.getNodeAccessor().setLabeledBy(node, Label.this);
                        NodeHelper.showMnemonicsProperty(node).addListener(mnemonicStateListener);
                        NodeHelper.setShowMnemonics(Label.this, NodeHelper.isShowMnemonics(node));
                    } else {
                        NodeHelper.setShowMnemonics(Label.this, false);
                    }
                    oldValue = node;
                }

                @Override public Object getBean() {
                    return Label.this;
                }

                @Override public String getName() {
                    return "labelFor";
                }
            };

        }
        return labelFor;
    }
    private ObjectProperty<Node> labelFor;

    public final void setLabelFor(Node value) { labelForProperty().setValue(value); }
    public final Node getLabelFor() { return labelFor == null ? null : labelFor.getValue(); }

    /***************************************************************************
     *                                                                         *
     * Methods                                                                 *
     *                                                                         *
     **************************************************************************/

    
{@inheritDoc} /** {@inheritDoc} */
    @Override protected Skin<?> createDefaultSkin() {
        return new LabelSkin(this);
    }

    /***************************************************************************
     *                                                                         *
     * CSS Support                                                             *
     *                                                                         *
     **************************************************************************/

    
Returns the initial focus traversable state of this control, for use
by the JavaFX CSS engine to correctly set its initial value. This method
is overridden as by default UI controls have focus traversable set to true,
but that is not appropriate for this control.
Since:
9/**
     * Returns the initial focus traversable state of this control, for use
     * by the JavaFX CSS engine to correctly set its initial value. This method
     * is overridden as by default UI controls have focus traversable set to true,
     * but that is not appropriate for this control.
     *
     * @since 9
     */
    @Override protected Boolean getInitialFocusTraversable() {
        return Boolean.FALSE;
    }

}