skrueger/geotools/CopyableUtil.java

/*******************************************************************************
 * Copyright (c) 2009 Martin O. J. Schmitz.
 * 
 * This file is part of the SCHMITZM library - a collection of utility 
 * classes based on Java 1.6, focusing (not only) on Java Swing 
 * and the Geotools library.
 * 
 * The SCHMITZM project is hosted at:
 * http://wald.intevation.org/projects/schmitzm/
 * 
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser 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 Lesser General Public License (license.txt)
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 * or try this link: http://www.gnu.org/licenses/lgpl.html
 * 
 * Contributors:
 *     Martin O. J. Schmitz - initial API and implementation
 *     Stefan A. Krüger - additional utility classes
 ******************************************************************************/

package skrueger.geotools;

/**
 * Some utility method for {@link Copyable}.
 * @author <a href="mailto:[email protected]">Martin Schmitz</a>
 */
public class CopyableUtil {
  
  /**
   * Copies an {@link Copyable} to another. If possible no new destination
   * instance is created, so the "original" destination object is
   * also returned.<br>
   * If {@code source} is {@code null}, the {@code dest} object
   * is irrelevant and {@code null} is returned. If {@code dest} is NULL
   * and {@code source} in not NULL, a new {@code source.copy()} is
   * returned. 
   * @param source the source object (can be {@code null})
   * @param dest   the object, the source values are copied to (can be {@code null})
   */
  public static <T extends Copyable<T>> T copyOrCreate(T source, T dest) {
    // If both objects are not NULL, the source Copyable can be applied
    // to destination Copyable
    if ( source != null && dest != null )
      source.copyTo( dest );
    // Otherwise: If source Copyable is not NULL, but destination a new
    //            destination object is created from source and returned
    else if ( source != null && dest == null )
      dest = source.copy();
    // Otherwise: source Copyable is NULL, so destination must also
    //            be NULL
    else 
      dest = null;
    
    return dest;
  }
}
1	mojays	449	/*******************************************************************************
2			* Copyright (c) 2009 Martin O. J. Schmitz.
3			*
4			* This file is part of the SCHMITZM library - a collection of utility
5			* classes based on Java 1.6, focusing (not only) on Java Swing
6			* and the Geotools library.
7			*
8			* The SCHMITZM project is hosted at:
9			* http://wald.intevation.org/projects/schmitzm/
10			*
11			* This program is free software; you can redistribute it and/or
12			* modify it under the terms of the GNU Lesser General Public License
13			* as published by the Free Software Foundation; either version 3
14			* of the License, or (at your option) any later version.
15			*
16			* This program is distributed in the hope that it will be useful,
17			* but WITHOUT ANY WARRANTY; without even the implied warranty of
18			* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19			* GNU General Public License for more details.
20			*
21			* You should have received a copy of the GNU Lesser General Public License (license.txt)
22			* along with this program; if not, write to the Free Software
23			* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
24			* or try this link: http://www.gnu.org/licenses/lgpl.html
25			*
26			* Contributors:
27			* Martin O. J. Schmitz - initial API and implementation
28			* Stefan A. Krüger - additional utility classes
29			******************************************************************************/
30
31			package skrueger.geotools;
32
33			/**
34			* Some utility method for {@link Copyable}.
35			* @author <a href="mailto:[email protected]">Martin Schmitz</a>
36			*/
37			public class CopyableUtil {
38
39			/**
40			* Copies an {@link Copyable} to another. If possible no new destination
41			* instance is created, so the "original" destination object is
42			* also returned.<br>
43			* If {@code source} is {@code null}, the {@code dest} object
44			* is irrelevant and {@code null} is returned. If {@code dest} is NULL
45			* and {@code source} in not NULL, a new {@code source.copy()} is
46			* returned.
47			* @param source the source object (can be {@code null})
48			* @param dest the object, the source values are copied to (can be {@code null})
49			*/
50			public static <T extends Copyable<T>> T copyOrCreate(T source, T dest) {
51			// If both objects are not NULL, the source Copyable can be applied
52			// to destination Copyable
53			if ( source != null && dest != null )
54			source.copyTo( dest );
55			// Otherwise: If source Copyable is not NULL, but destination a new
56			// destination object is created from source and returned
57			else if ( source != null && dest == null )
58			dest = source.copy();
59			// Otherwise: source Copyable is NULL, so destination must also
60			// be NULL
61			else
62			dest = null;
63
64			return dest;
65			}
66			}