Spacer.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.framework.uitools;

// JDK
import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.LayoutManager;
import javax.swing.JComponent;

/**
 * A <code>Spacer</code> is a light component used to add space between
 * components in order to align them.
 *
 * @version 10.0.3
 * @author Pascal Filion
 */
public final class Spacer extends JComponent
{
    /**
     * The minimum size this spacer should have as its minimum and preferred
     * sizes.
     */
    private final Dimension minimumSize;

    /**
     * Creates a new <code>Spacer</code>.
     */
    public Spacer()
    {
        this(0);
    }

    /**
     * @param preferredSize
     */
    public void setPreferredSize(Dimension preferredSize)
    {
        super.setPreferredSize(preferredSize);

        if (preferredSize != null)
            setVisible(preferredSize.width > 0);
    }

    /**
     * Creates a new <code>Spacer</code>.
     *
     * @param minimumWidth The minimum width this spacer should have as its
     * preferred size
     */
    public Spacer(int minimumWidth)
    {
        super();

        this.minimumSize = new Dimension(minimumWidth, 0);
        setLayout(new SpacerLayout());
    }

    /**
     * This <code>LayoutManager</code> returns the {@link Spacer#minimumWidth}
     * for the preferred and minimum width.
     */
    private class SpacerLayout implements LayoutManager
    {
        public void addLayoutComponent(String name, Component component) {}
        public void layoutContainer(Container parent) {}
        public void removeLayoutComponent(Component component) {}

        public Dimension minimumLayoutSize(Container parent)
        {
            return (Dimension) Spacer.this.minimumSize.clone();
        }

        public Dimension preferredLayoutSize(Container parent)
        {
            return (Dimension) Spacer.this.minimumSize.clone();
        }
    }
}