| /* |
| * 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; |
| } |
| } |
