/*
 * Copyright (C) 2010 Brockmann Consult GmbH (info@brockmann-consult.de)
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 3 of the License, or (at your option)
 * any later version.
 * This program 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 for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, see http://www.gnu.org/licenses/
 */
package com.bc.ceres.swing.binding;

import com.bc.ceres.binding.PropertyDescriptor;
import com.bc.ceres.core.Assert;
import com.bc.ceres.core.ServiceRegistry;
import com.bc.ceres.core.ServiceRegistryManager;
import com.bc.ceres.swing.binding.internal.TextFieldEditor;

import java.util.ServiceLoader;

/**
 * A registry for {@link PropertyEditor}.
 *
 * @author Marco Zuehlke
 * @version $Revision$ $Date$
 * @since BEAM 4.6
 */
public class PropertyEditorRegistry {

    private static PropertyEditorRegistry instance;

    private final ServiceRegistry<PropertyEditor> registry;
    private final PropertyEditor defaultEditor;

    private PropertyEditorRegistry() {
        registry = ServiceRegistryManager.getInstance().getServiceRegistry(PropertyEditor.class);

        final ServiceLoader<PropertyEditor> serviceLoader = ServiceLoader.load(PropertyEditor.class);
        for (final PropertyEditor propertyEditor : serviceLoader) {
            registry.addService(propertyEditor);
        }
        defaultEditor = registry.getService(TextFieldEditor.class.getName());
    }

    public static synchronized PropertyEditorRegistry getInstance() {
        if (instance == null) {
            instance = new PropertyEditorRegistry();
        }
        return instance;
    }

    public static synchronized void setInstance(PropertyEditorRegistry registry) {
        instance = registry;
    }

    /**
     * Gets a {@link PropertyEditor} by its class name.
     *
     * @param className The class name of the {@link PropertyEditor}.
     *
     * @return the value editor or {@code null} if no editor exist for the given class name.
     */
    public PropertyEditor getPropertyEditor(String className) {
        return registry.getService(className);
    }

    /**
     * Finds a matching {@link PropertyEditor} for the given {@link com.bc.ceres.binding.PropertyDescriptor}.
     * <p/>
     * At first , if set, the property {@code "propertyEditor"} of the property descriptor
     * is used. Afterwards all registered {@link PropertyEditor}s are tested,
     * whether the can provide an editor. As a fallback a {@link TextFieldEditor} is returned.
     *
     * @param propertyDescriptor the value descriptor
     *
     * @return the editor that can edit values described by the value descriptor
     */
    public PropertyEditor findPropertyEditor(PropertyDescriptor propertyDescriptor) {
        Assert.notNull(propertyDescriptor, "propertyDescriptor");
        PropertyEditor propertyEditor = (PropertyEditor) propertyDescriptor.getAttribute("propertyEditor");
        if (propertyEditor != null) {
            return propertyEditor;
        }
        for (PropertyEditor editor : registry.getServices()) {
            if (editor.isValidFor(propertyDescriptor)) {
                return editor;
            }
        }
        return defaultEditor;
    }
}