/*******************************************************************************
 * Copyright (c) 2008 Oracle. All rights reserved.
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0, which accompanies this distribution
 * and is available at http://www.eclipse.org/legal/epl-v10.html.
 *
 * Contributors:
 *     Oracle - initial API and implementation
 ******************************************************************************/
package org.eclipse.jpt.ui.internal.mappings.db;

import java.util.Iterator;

import org.eclipse.jpt.core.JpaNode;
import org.eclipse.jpt.db.Database;
import org.eclipse.jpt.ui.WidgetFactory;
import org.eclipse.jpt.ui.internal.widgets.Pane;
import org.eclipse.jpt.utility.internal.iterators.EmptyIterator;
import org.eclipse.jpt.utility.model.value.PropertyValueModel;
import org.eclipse.swt.widgets.Composite;

/**
 * This database object combo handles showing the database's schemas.
 *
 * @version 2.0
 * @since 2.0
 */
public abstract class SchemaCombo<T extends JpaNode> extends DatabaseObjectCombo<T>
{
	/**
	 * Creates a new <code>SchemaCombo</code>.
	 *
	 * @param parentPane The parent container of this one
	 * @param parent The parent container
	 */
	public SchemaCombo(Pane<? extends T> parentPane,
	                   Composite parent)
	{
		super(parentPane, parent);
	}

	/**
	 * Creates a new <code>SchemaCombo</code>.
	 *
	 * @param parentPane The parent container of this one
	 * @param subjectHolder The holder of this pane's subject
	 * @param parent The parent container
	 */
	public SchemaCombo(Pane<?> parentPane,
	                   PropertyValueModel<? extends T> subjectHolder,
	                   Composite parent)
	{
		super(parentPane, subjectHolder, parent);
	}

	/**
	 * Creates a new <code>SchemaCombo</code>.
	 *
	 * @param subjectHolder The holder of the subject
	 * @param parent The parent container
	 * @param widgetFactory The factory used to create various common widgets
	 */
	public SchemaCombo(PropertyValueModel<? extends T> subjectHolder,
	                   Composite parent,
	                   WidgetFactory widgetFactory)
	{
		super(subjectHolder, parent, widgetFactory);
	}

	@Override
	protected Iterator<String> values() {
		Database db = this.getDatabase();
		return (db == null) ? EmptyIterator.<String>instance() : db.schemaNames();
	}

}