/*
 * Copyright (c) 2002-2011 JGoodies Karsten Lentzsch. All Rights Reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *  o Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 *  o Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 *  o Neither the name of JGoodies Karsten Lentzsch nor the names of
 *    its contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package com.jgoodies.binding.adapter;

import static com.jgoodies.common.base.Preconditions.checkNotNull;

import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;

import javax.swing.ButtonGroup;
import javax.swing.JToggleButton;

import com.jgoodies.binding.value.ValueModel;
import com.jgoodies.common.base.Objects;

/**
 * Converts ValueModels to the ToggleButtonModel interface. Useful to bind
 * JRadioButtons and JRadioButtonMenuItems to a ValueModel.<p>
 *
 * This adapter holds a <em>choice</em> object that is used to determine
 * the selection state if the underlying subject ValueModel changes its value.
 * This model is selected if the subject's value equals the choice object.
 * And if the selection is set, the choice object is set to the subject.<p>
 *
 * <strong>Note:</strong> You must not use a ButtonGroup with this adapter.
 * The RadioButtonAdapter ensures that only one choice is selected by sharing
 * a single subject ValueModel - at least if all choice values differ.
 * See also the example below.<p>
 *
 * <strong>Example:</strong><pre>
 * // Recommended binding style using a factory
 * PresentationModel presentationModel = new PresentationModel(printerSettings);
 * ValueModel orientationModel =
 *     presentationModel.getModel(PrinterSettings.PROPERTYNAME_ORIENTATION);
 * JRadioButton landscapeButton = BasicComponentFactory.createRadioButton(
 *     orientationModel, PrinterSettings.LANDSCAPE, "Landscape");
 * JRadioButton portraitButton  = BasicComponentFactory.createRadioButton(
 *     orientationModel, PrinterSettings.PORTRAIT, "Portrait");
 *
 * // Binding using the Bindings class
 * ValueModel orientationModel =
 *     presentationModel.getModel(PrinterSettings.PROPERTYNAME_ORIENTATION);
 * JRadioButton landscapeButton = new JRadioButton("Landscape");
 * Bindings.bind(landscapeButton, orientationModel, "landscape");
 *
 * JRadioButton portraitButton = new JRadioButton("Portrait");
 * Bindings.bind(portraitButton, orientationModel, "portrait");
 *
 * // Hand-made style
 * ValueModel orientationModel =
 *     presentationModel.getModel(PrinterSettings.PROPERTYNAME_ORIENTATION);
 * JRadioButton landscapeButton = new JRadioButton("Landscape");
 * landscapeButton.setModel(new RadioButtonAdapter(model, "landscape");
 *
 * JRadioButton portraitButton = new JRadioButton("Portrait");
 * portraitButton.setModel(new RadioButtonAdapter(model, "portrait");
 * </pre>
 *
 * @author Karsten Lentzsch
 * @version $Revision: 1.11 $
 *
 * @see javax.swing.ButtonModel
 * @see javax.swing.JRadioButton
 * @see javax.swing.JRadioButtonMenuItem
 */

public final class RadioButtonAdapter extends JToggleButton.ToggleButtonModel {

    /**
     * Refers to the underlying ValueModel that stores the state.
     */
    private final ValueModel subject;

    /**
     * Holds the object that is compared with the subject's value
     * to determine whether this adapter is selected or not.
     */
    private final Object choice;


    // Instance Creation ****************************************************

    /**
     * Constructs a RadioButtonAdapter on the given subject ValueModel
     * for the specified choice.
     * The created adapter will be selected if and only if the
     * subject's initial value equals the given {@code choice}.
     *
     * @param subject the subject that holds the value
     * @param choice the choice that indicates that this adapter is selected
     *
     * @throws NullPointerException if the subject is {@code null}
     */
    public RadioButtonAdapter(ValueModel subject, Object choice) {
        this.subject = checkNotNull(subject, "The subject must not be null.");
        this.choice = choice;
        subject.addValueChangeListener(new SubjectValueChangeHandler());
        updateSelectedState();
    }


    // ToggleButtonModel Implementation ***********************************

    /**
     * First, the subject value is set to this adapter's choice value if
     * the argument is {@code true}. Second, this adapter's state is set
     * to the then current subject value. The latter ensures that the selection
     * state is synchronized with the subject - even if the subject rejects
     * the change.<p>
     *
     * Does nothing if the boolean argument is {@code false},
     * or if this adapter is already selected.
     *
     * @param b {@code true} sets the choice value as subject value,
     *     and is intended to select this adapter (although it may not happen);
     *     {@code false} does nothing
     */
    @Override
    public void setSelected(boolean b) {
        if (!b || isSelected()) {
            return;
        }
        subject.setValue(choice);
        updateSelectedState();
    }


    // Safety Check ***********************************************************

    /**
     * Throws an UnsupportedOperationException if the group
     * is not {@code null}. You need not and must not
     * use a ButtonGroup with a set of RadioButtonAdapters.
     * RadioButtonAdapters form a group by sharing the same
     * subject ValueModel.
     *
     * @param group the {@code ButtonGroup} that will be rejected
     *
     * @throws UnsupportedOperationException if the group is not {@code null}.
     */
    @Override
    public void setGroup(ButtonGroup group) {
        if (group != null) {
            throw new UnsupportedOperationException(
                    "You need not and must not use a ButtonGroup "
                  + "with a set of RadioButtonAdapters. These form "
                  + "a group by sharing the same subject ValueModel.");
        }
    }


    /**
     * Updates this adapter's selected state to reflect
     * whether the subject holds the selected value or not.
     * Does not modify the subject value.
     */
    private void updateSelectedState() {
        boolean subjectHoldsChoiceValue =
            Objects.equals(choice, subject.getValue());
        super.setSelected(subjectHoldsChoiceValue);
    }


    // Event Handling *********************************************************

    /**
     * Handles changes in the subject's value.
     */
    private final class SubjectValueChangeHandler implements PropertyChangeListener {

        /**
         * The subject value has changed. Updates this adapter's selected
         * state to reflect whether the subject holds the choice value or not.
         *
         * @param evt the property change event fired by the subject
         */
        public void propertyChange(PropertyChangeEvent evt) {
            updateSelectedState();
        }

    }

}
