| J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2003 Sun Microsystems, Inc. All Rights Reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun in the LICENSE file that accompanied this code. |
| 10 | * |
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 14 | * version 2 for more details (a copy is included in the LICENSE file that |
| 15 | * accompanied this code). |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License version |
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package sun.font; |
| 27 | |
| 28 | /* |
| 29 | * This class is used so that a java.awt.Font does not directly |
| 30 | * reference a Font2D object. This introduces occasional minor |
| 31 | * de-referencing overhead but increases robustness of the |
| 32 | * implementation when "bad fonts" are encountered. |
| 33 | * A handle is created by a Font2D constructor and references |
| 34 | * the Font2D itself. In the event that the Font2D implementation |
| 35 | * determines it the font resource has errors (a bad font file) |
| 36 | * it makes its handle point at another "stable" Font2D. |
| 37 | * Once all referers no longer have a reference to the Font2D it |
| 38 | * may be GC'd and its resources freed. |
| 39 | * This does not immediately help in the case that objects are |
| 40 | * already using a bad Font2D (ie have already dereferenced the |
| 41 | * handle) so there is a window for more problems. However this |
| 42 | * is already the case as this is the code which must detect the |
| 43 | * problem. |
| 44 | * However there is also the possibility of intercepting problems |
| 45 | * even when a font2D reference is already directly held. Certain |
| 46 | * validation points may check that font2Dhandle.font2D == font2D |
| 47 | * If this is not true, then this font2D is not valid. Arguably |
| 48 | * this check also just needs to be a de-referencing assignment : |
| 49 | * font2D = font2DHandle.font2D. |
| 50 | * The net effect of these steps is that very soon after a font |
| 51 | * is identified as bad, that references and uses of it will be |
| 52 | * eliminated. |
| 53 | * In the initial implementation a Font2DHandle is what is held by |
| 54 | * - java.awt.Font |
| 55 | * - FontManager.initialisedFonts map |
| 56 | * Font2D is held by |
| 57 | * - FontFamily objects |
| 58 | * - FontManager.registeredFonts map |
| 59 | * - FontInfo object on a SunGraphics2D |
| 60 | * |
| 61 | * On discovering a bad font, all but the latter remove references to |
| 62 | * the font. See FontManager.deRegisterBadFont(Font2D) |
| 63 | */ |
| 64 | |
| 65 | public final class Font2DHandle { |
| 66 | |
| 67 | public Font2D font2D; |
| 68 | |
| 69 | public Font2DHandle(Font2D font) { |
| 70 | font2D = font; |
| 71 | } |
| 72 | } |