/*

 * Copyright (c) 2003, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code 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

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package sun.font;

/*

 * This class is used so that a java.awt.Font does not directly

 * reference a Font2D object. This introduces occasional minor

 * de-referencing overhead but increases robustness of the

 * implementation when "bad fonts" are encountered.

 * A handle is created by a Font2D constructor and references

 * the Font2D itself. In the event that the Font2D implementation

 * determines it the font resource has errors (a bad font file)

 * it makes its handle point at another "stable" Font2D.

 * Once all referers no longer have a reference to the Font2D it

 * may be GC'd and its resources freed.

 * This does not immediately help in the case that objects are

 * already using a bad Font2D (ie have already dereferenced the

 * handle) so there is a window for more problems. However this

 * is already the case as this is the code which must detect the

 * problem.

 * However there is also the possibility of intercepting problems

 * even when a font2D reference is already directly held. Certain

 * validation points may check that font2Dhandle.font2D == font2D

 * If this is not true, then this font2D is not valid. Arguably

 * this check also just needs to be a de-referencing assignment :

 * font2D = font2DHandle.font2D.

 * The net effect of these steps is that very soon after a font

 * is identified as bad, that references and uses of it will be

 * eliminated.

 * In the initial implementation a Font2DHandle is what is held by

 * - java.awt.Font

 * - FontManager.initialisedFonts map

 * Font2D is held by

 * - FontFamily objects

 * - FontManager.registeredFonts map

 * - FontInfo object on a SunGraphics2D

 *

 * On discovering a bad font, all but the latter remove references to

 * the font. See FontManager.deRegisterBadFont(Font2D)

 */

public final class Font2DHandle {

    public Font2D font2D;

    public Font2DHandle(Font2D font) {

        font2D = font;

    }

}