RadioButtonModelAdapter.java

/*******************************************************************************
 * Copyright (c) 1998, 2015 Oracle and/or its affiliates. All rights reserved.
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
 * which accompanies this distribution.
 * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
 * and the Eclipse Distribution License is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * Contributors:
 *     Oracle - initial API and implementation from Oracle TopLink
******************************************************************************/
package org.eclipse.persistence.tools.workbench.uitools.app.swing;

import org.eclipse.persistence.tools.workbench.uitools.app.FilteringPropertyValueModel;
import org.eclipse.persistence.tools.workbench.uitools.app.PropertyValueModel;
import org.eclipse.persistence.tools.workbench.uitools.app.TransformationPropertyValueModel;
import org.eclipse.persistence.tools.workbench.utility.BidiTransformer;
import org.eclipse.persistence.tools.workbench.utility.filters.BidiFilter;


/**
 * This javax.swing.ButtonModel can be used to keep a listener
 * (e.g. a JRadioButton) in synch with a (typically shared)
 * PropertyValueModel that holds one value out of a set of values.
 *
 * NOTE: Do *not* use this model with a ButtonGroup, since the
 * shared value holder and the wrappers built by this adapter will
 * keep the appropriate radio button checked. Also, this allows
 * us to uncheck all the radio buttons in a group when the shared
 * value is null.
 */
public class RadioButtonModelAdapter extends ToggleButtonModelAdapter {


    // ********** constructors **********

    /**
     * Constructor - the value holder is required.
     */
    public RadioButtonModelAdapter(PropertyValueModel valueHolder, Object buttonValue, boolean defaultValue) {
        super(buildBooleanHolder(valueHolder, buttonValue), defaultValue);
    }

    /**
     * Constructor - the value holder is required.
     * The default value will be false.
     */
    public RadioButtonModelAdapter(PropertyValueModel valueHolder, Object buttonValue) {
        super(buildBooleanHolder(valueHolder, buttonValue));
    }


    // ********** static methods **********

    /**
     * Build up a set of wrappers that will convert the
     * specified value holder and button value to/from a boolean.
     *
     * If the value holder's value matches the button value,
     * the wrapper will return true. Likewise, if the value holder's
     * value is set to true, the wrapper will set the value holder's
     * value to the button value.
     */
    public static PropertyValueModel buildBooleanHolder(PropertyValueModel valueHolder, Object buttonValue) {
        PropertyValueModel filteringPVM = new FilteringPropertyValueModel(valueHolder, new RadioButtonFilter(buttonValue));
        return new TransformationPropertyValueModel(filteringPVM, new RadioButtonTransformer(buttonValue));
    }


    // ********** overrides **********

    /**
     * The user cannot de-select a radio button - the user
     * can only *select* a radio button. Only the model can
     * cause a radio button to be de-selected. We use the
     * ARMED flag to indicate whether we are being de-selected
     * by the user.
     * @see ToggleButtonModelAdapter#setSelected(boolean)
     */
    public void setSelected(boolean b) {
        // do not allow the user to de-select a radio button
        // radio buttons can
        if ((b == false) && this.isArmed()) {
            return;
        }
        super.setSelected(b);
    }


    // ********** inner classes **********

    /**
     * This filter will only pass through a new value to the wrapped
     * value holder when it matches the configured button value.
     */
    public static class RadioButtonFilter implements BidiFilter {
        private Object buttonValue;

        public RadioButtonFilter(Object buttonValue) {
            super();
            this.buttonValue = buttonValue;
        }

        /**
         * always return the wrapped value
         */
        public boolean accept(Object value) {
            return true;
        }

        /**
         * pass through the value to the wrapped property value model
         * *only* when it matches our button value
         */
        public boolean reverseAccept(Object value) {
            return value == this.buttonValue;
        }

    }

    /**
     * This transformer will convert the wrapped value to Boolean.TRUE
     * when it matches the configured button value.
     */
    public static class RadioButtonTransformer implements BidiTransformer {
        private Object buttonValue;

        public RadioButtonTransformer(Object buttonValue) {
            super();
            this.buttonValue = buttonValue;
        }

        /**
         * if the wrapped value matches our button value return true,
         * if it is some other value return false;
         * but if it is null simply pass it through because it will cause the
         * button model's default value to be used
         */
        public Object transform(Object value) {
            return (value == null) ? null : Boolean.valueOf(value == this.buttonValue);
        }

        /**
         * if the new value is true, pass through the our button value;
         * otherwise pass through null
         */
        public Object reverseTransform(Object value) {
            return (((Boolean) value).booleanValue()) ? this.buttonValue : null;
        }

    }

}