001    /* TransformAttribute.java --
002       Copyright (C) 2003, 2005  Free Software Foundation, Inc.
003    
004    This file is part of GNU Classpath.
005    
006    GNU Classpath is free software; you can redistribute it and/or modify
007    it under the terms of the GNU General Public License as published by
008    the Free Software Foundation; either version 2, or (at your option)
009    any later version.
010    
011    GNU Classpath is distributed in the hope that it will be useful, but
012    WITHOUT ANY WARRANTY; without even the implied warranty of
013    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014    General Public License for more details.
015    
016    You should have received a copy of the GNU General Public License
017    along with GNU Classpath; see the file COPYING.  If not, write to the
018    Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019    02110-1301 USA.
020    
021    Linking this library statically or dynamically with other modules is
022    making a combined work based on this library.  Thus, the terms and
023    conditions of the GNU General Public License cover the whole
024    combination.
025    
026    As a special exception, the copyright holders of this library give you
027    permission to link this library with independent modules to produce an
028    executable, regardless of the license terms of these independent
029    modules, and to copy and distribute the resulting executable under
030    terms of your choice, provided that you also meet, for each linked
031    independent module, the terms and conditions of the license of that
032    module.  An independent module is a module which is not derived from
033    or based on this library.  If you modify this library, you may extend
034    this exception to your version of the library, but you are not
035    obligated to do so.  If you do not wish to do so, delete this
036    exception statement from your version. */
037    
038    
039    package java.awt.font;
040    
041    import java.awt.geom.AffineTransform;
042    import java.io.Serializable;
043    
044    /**
045     * This class provides a mechanism for using an {@link AffineTransform} as
046     * an <i>immutable</i> attribute (for example, in the
047     * {@link java.text.AttributedString} class).  Any transform passed to
048     * this class is copied before being stored, and any transform handed out
049     * by this class is a copy of the stored transform.  In this way, it is
050     * not possible to modify the stored transform.
051     *
052     * @author Michael Koch
053     */
054    public final class TransformAttribute implements Serializable
055    {
056      private static final long serialVersionUID = 3356247357827709530L;
057    
058      private AffineTransform affineTransform;
059    
060      /**
061       * Creates a new attribute that contains a copy of the given transform.
062       *
063       * @param transform  the transform (<code>null</code> not permitted).
064       *
065       * @throws IllegalArgumentException if <code>transform</code> is
066       *         <code>null</code>.
067       */
068      public TransformAttribute (AffineTransform transform)
069      {
070        if (transform == null)
071          {
072            throw new IllegalArgumentException("Null 'transform' not permitted.");
073          }
074        this.affineTransform = new AffineTransform (transform);
075      }
076    
077      /**
078       * Returns a copy of the transform contained by this attribute.
079       *
080       * @return A copy of the transform.
081       */
082      public AffineTransform getTransform ()
083      {
084        return (AffineTransform) affineTransform.clone();
085      }
086    
087      /**
088       * Returns <code>true</code> if the transform contained by this attribute is
089       * an identity transform, and <code>false</code> otherwise.
090       *
091       * @return <code>true</code> if the transform contained by this attribute is
092       * an identity transform, and <code>false</code> otherwise.
093       *
094       * @since 1.4
095       */
096      public boolean isIdentity ()
097      {
098        return (affineTransform == null ? false : affineTransform.isIdentity ());
099      }
100    }